Using the Internet for Surveys and Health Research This paper concerns the use of the Internet in the research process , from identifying research issues through qualitative research , through using the Web for surveys and clinical trials , to pre-publishing and publishing research results . Material published on the Internet may be a valuable resource for researchers desiring to understand people and the social and cultural contexts within which they live outside of experimental settings , with due emphasis on the interpretations , experiences , and views of ` real world ' people . Reviews of information posted by consumers on the Internet may help to identify health beliefs , common topics , motives , information , and emotional needs of patients , and point to areas where research is needed . The Internet can further be used for survey research . Internet-based surveys may be conducted by means of interactive interviews or by questionnaires designed for self-completion . Electronic one-to-one interviews can be conducted via e-mail or using chat rooms . Questionnaires can be administered by e-mail -LRB- e.g. using mailing lists -RRB- , by posting to newsgroups , and on the Web using fill-in forms . In `` open '' web-based surveys , selection bias occurs due to the non-representative nature of the Internet population , and -LRB- more importantly -RRB- through self-selection of participants , i.e. the non-representative nature of respondents , also called the ` volunteer effect ' . A synopsis of important techniques and tips for implementing Web-based surveys is given . Ethical issues involved in any type of online research are discussed . Internet addresses for finding methods and protocols are provided . The Web is also being used to assist in the identification and conduction of clinical trials . For example , the web can be used by researchers doing a systematic review who are looking for unpublished trials . Finally , the web is used for two distinct types of electronic publication . Type 1 publication is unrefereed publication of protocols or work in progress -LRB- a ` post-publication ' peer review process may take place -RRB- , whereas Type 2 publication is peer-reviewed and will ordinarily take place in online journals . Identifying issues for qualitative research As the most comprehensive archive of written material representing our world and people 's opinions , concerns , and desires -LRB- in industrialized countries -RRB- , the Internet can be used to identify ` issues ' for qualitative -LRB- descriptive -RRB- research and to generate hypotheses . Material published on the Internet may be a valuable resource for researchers desiring to understand people and the social and cultural contexts within which they live -- outside of experimental settings -- with due emphasis on the interpretations , experiences , and views of ` real world ' people . Reviews of information posted by consumers on the Internet may help to identify health beliefs , common topics , motives , information , and emotional needs of patients , and point to areas where research is needed . Comparing recommendations found on the Web against evidence-based guidelines is one way to identify areas where there is a gap between opinion and evidence , or where there is a need for clinical innovation . The accessibility of information for analysis and the anonymity of the Internet allow researchers to analyse text and narratives on Web sites , to use newsgroups as global focus groups , and to conduct interviews and surveys via e-mail , chat rooms , Web sites , or newsgroups.Topics suited to qualitative research include : Analysis of interactive communications -LRB- e.g. e-mail -RRB- . Study of online communities -LRB- virtual self-help groups , newsgroups , mailing lists -RRB- . Investigation of communication processes between patients and professionals . Study of consumer preferences , patient concerns , and information needs . Exploration of the ` epidemiology of health information ' on the Web -LSB- 1-2 -RSB- . The Internet population is unrepresentative of the general population , restricting the use of the Internet for quantitative studies -LRB- i.e. studies focusing on measurement -RRB- . Qualitative studies , however , do not require representative samples : ` In qualitative research we are not interested in an average view of a patient population , but want to gain an in-depth understanding of the experience of particular individuals or groups ; we should therefore deliberately seek out individuals or groups who fit the bill ' -LSB- 3 -RSB- . Three different research methodologies for qualitative research on the Internet may be distinguished : Passive analysis : For example , studying information on Web sites or interactions in newsgroups , mailing lists , and chat rooms -- without researchers actively involving themselves . Active analysis : Also called participant observation ; the researcher participates in the communication process , often without disclosing their identity as researcher . For example , they may ask questions in a patient discussion group implying that she or he is a fellow patient . Such studies often involve elements of deception , unless the researcher is a sufferer him - or herself . Interviews and surveys : See below . Examples of these three types of qualitative research on the Internet are available elsewhere -LSB- 1 -RSB- . Using the Internet for surveys Using the Internet for surveys requires an awareness of methodologies , selection bias , and technical issues . Methodological issues Internet-based surveys may be conducted by means of interactive interviews or by questionnaires designed for self-completion . Electronic one-to-one interviews can be conducted via e-mail or using chat rooms . Questionnaires can be administered by e-mail -LRB- e.g. using mailing lists -RRB- , by posting to newsgroups , and on the Web using fill-in forms . When e-mail is used to administer questionnaires , messages are usually sent to a selected group with a known number of participants , thus allowing calculation of the response rate . Surveys posted to newsgroups may request that the completed questionnaire is posted back to the researcher , but it is impossible to know who and how many people read the questionnaire . If Web-based forms are used , questionnaires can be placed in a password-protected area of a Web site -LRB- i.e. participation by invitation or registration only -RRB- , or alternatively they may be open to the public -LRB- i.e. any site visitor can complete the survey -RRB- . The latter option makes calculation of a response rate more difficult but not impossible : the number of people who access -LRB- without necessarily completing -RRB- the questionnaire is counted and used as the denominator . Web-based surveys have the advantage that the respondent can remain anonymous -LRB- as opposed to e-mail surveys , where the e-mail address of the responder is revealed -RRB- . Furthermore , they are very convenient for the researcher , as responses can be directly stored in a database where they are immediately accessible for analysis . Electronic interviews and surveys -LRB- ` e-surveys ' -RRB- are emerging scientific research methodologies , pioneered by communication scientists , sociologists , and psychologists , although their use for health-related research is still in its infancy -LSB- 4-10 -RSB- . Examples of health-related research include : A Web-based survey on the effects of ulcerative colitis on quality of life -LSB- 11 -RSB- . Collection of clinical data from atopy patients -LSB- 12 -RSB- . A Web-based survey looking at complementary and alternative medicine use by patients with inflammatory bowel disease and Internet access -LSB- 13 -RSB- . A survey of dentists regarding the usefulness of the Internet in supporting patient care -LSB- 14,15 -RSB- . Guidelines for Web-based surveys Scenarios that may be suitable for a Web-based survey Respondent features : Respondents are already avid Internet users ; e-mail addresses known for reminder messages . Respondents are enthusiastic form fillers ; will not require monetary incentives . Need for respondents covering a wide geographical area -LRB- e.g. rare clinical special ties , diseases -RRB- . Respondents are known to match non-respondents and even non-Internet users on key variables . Survey features : Need for complex branching , interactive questionnaire or multimedia as part of the survey instrument . Survey content will evolve fast -LRB- e.g. Delphi method surveys use repeating rounds of revised questionnaires delivered over a short period , incorporating aggregate results from previous rounds until convergence is achieved -RRB- . Intent is to document bizarre , rare phenomena whose simple occurrence is of interest . No need for representative results : collecting ideas vs. hypothesis testing . Investigator features : Limited budget for mailing and data processing , but good in-house Web skills . Precautions can be taken against multiple responses by same individual , password sharing . Web survey forms have been piloted with representative participants and demonstrate acceptable validity and reliability with most platform , browser , and Internet access provider combinations . Data is required fast in a readily analysed form . Scenarios that are unsuitable for a Web-based survey Respondent features : Target group is under-represented on Internet ; e.g. the underprivileged , elderly people . Target group is concerned , however unreasonably , about privacy aspects . Target group requires substantial incentives to complete the survey . Need for a representative sample . Survey features : Need for very accurate timing data on participants -LRB- inaccuracies in the range of seconds are added due to network transmission times , unless JavaScript or Java applets are used ; see Glossary -RRB- or observational data on participants . An existing paper instrument has been carefully validated on target group . Need to capture qualitative data or observations about participants . Wish to reach the same group of participants in the same way months or years later . Investigator features : Limited in-house Web or Java expertise but existing desktop publishing and mailing facility . E-surveys may be part of a qualitative research process , but results can be analysed quantitatively as long as researchers are aware of potential bias -LRB- see below -RRB- . In addition to gathering data , the Internet may also be used in the course of developing questionnaires , as it allows rapid prototyping and pilot testing of instruments , e.g. to evaluate the effect of framing the questions differently -LSB- 16 -RSB- . Several studies have checked the validity of Web-based surveys by comparing the results of studies conducted on the Web with identical studies in the real world . These seem to suggest that the validity and reliability of data obtained online are comparable to those obtained by classical methods -LSB- 4,5,17-19 -RSB- . However , issues of generalizability -LRB- mainly due to selection bias , discussed in detail below -RRB- remain important considerations , and the researcher should select his or her research question and interpret the results with care.The benefits and problems of Web-based surveys have been summarized by Wyatt , who suggests guidelines for when they may be appropriate -LRB- see Box 1 -RRB- -LSB- 20 -RSB- . Selection bias In ` open ' surveys conducted via the Internet where Web users , newsgroup readers , or mailing list subscribers are invited to participate by completing a questionnaire , selection bias is a major factor limiting the generalizability -LRB- external validity -RRB- of results . Selection bias occurs due to : The non-representative nature of the Internet population . The self-selection of participants , i.e. the non-representative nature of respondents , also called the ` volunteer effect ' -LSB- 21 -RSB- . The non-representative nature of Internet demographics was briefly considered earlier . Considering whether the topic chosen for study is suitable for the Internet population is the first and probably the most important step in minimizing bias , thus maximizing response rates and increasing the external validity of the results -LSB- 20 -RSB- . For example , targeting elderly homeless alcoholics is unsuitable for an Internet survey and the results are likely to be heavily skewed by hoax responses . Self-selection bias originates from the fact that people are more likely to respond to questionnaires if they see items which interest them , e.g. because they are affected by the items asked about , or because they are attracted by the incentives offered for participating . As people who respond almost certainly have different characteristics than those who do not , the results are likely to be biased.This kind of selection bias is more serious than the bias arising from the non-representative nature of the population , because the researcher deals with a myriad of unknown factors and has little opportunity to interpret his or her results accordingly . Such bias may be exacerbated via loaded incentives -LRB- e.g. typical ` male ' incentives such as computer equipment -RRB- . Evidence suggests women are generally more interested in health topics and exhibit more active information-seeking behaviour -LSB- 22 -RSB- , so are more likely to volunteer participation in health questionnaires . For Web surveys , the potential for self-selection bias can be estimated by measuring the response rate , expressed as the number of people completing the questionnaire divided by those who viewed it -LRB- cf. the participation rate , expressed as the number of site visitors viewing the questionnaire divided by the total number of site visitors -RRB- . Technical issues Although a detailed analysis is beyond the scope of this chapter , a synopsis of important techniques and tips for implementing Web-based surveys provides some insight into the difficulties faced by survey designers -LRB- see Box 2 -RRB- . Technical issues in implementing Web-based surveys Use of ` cookies ' Cookies can assign a unique identifier to every questionnaire viewer , useful for determining response and participation rates , and for filtering out multiple responses by the same person . As cookies may be regarded with suspicion , we recommend that researchers openly state that cookies will be sent -LRB- and the reasons for this -RRB- ; set the cookie to expire on the day that data collection ceases ; and publish a privacy policy . Measuring response time The time needed to complete a questionnaire can be readily calculated by subtracting the time a form was called up by the browser from the time it was submitted using an automatic time-stamp . The response time may be used to exclude respondents who fill in the questionnaire too quickly : this may identify hoax responses , where respondents do n't read the questions . Avoiding missing data Forms can be configured to automatically reject incomplete questionnaires and point out missing or contradictory items . Checks can be made on the client -LRB- p. 9 -RRB- prior to submission , or following submission to the server -LRB- where incomplete responses can also be analysed , e.g. during a questionnaire pilot -RRB- . Maximizing response rate The number of contacts , personalized contacts , and contact with participants before the actual survey are the factors most associated with higher response rates in Web surveys -LSB- 23 -RSB- . Incentives increase the risk of selection bias -LRB- see text -RRB- , but less so if cash is offered . Perhaps the best incentive -LRB- and the easiest to deliver via the Internet -RRB- is the promise of survey results or personalized answers -LRB- e.g. a score -RRB- . The option to complete questionnaires anonymously avoids wariness associated with requests for personal information -LRB- e.g. an e-mail address -RRB- , but increases the risk of hoax responses . Researchers should be open about who is behind the study , what the aim is , and provide opportunities for feedback . Although postal surveys are superior to e-mail surveys with regard to response rate , online surveys are much cheaper -LSB- 24,25 -RSB- . Schleyer -LSB- 15 -RSB- estimated that the cost of their Web-based survey was 38 percent less than that of an equivalent mail survey and presented a general formula for calculating break-even points between electronic and hard-copy surveys . Jones gave figures of 92 p per reply for postal surveys , 35 p for e-mail , and 41 p for the Web -LSB- 24 -RSB- . Randomizing items Scripting languages may be used to build dynamic questionnaires -LRB- as opposed to static forms -RRB- that look different for certain user groups or which randomize certain aspects of the questionnaire -LRB- e.g. the order of the items -RRB- . This can be useful to exclude possible systematic influences of the order of the items upon responses . Ethical issues The ethical issues involved in any type of online research should not be forgotten -LSB- 1,26-31 -RSB- . These include informed consent as a basic ethical tenet of scientific research on human populations -LSB- 32 -RSB- , protection of privacy , and avoiding psychological harm . In qualitative research on the Web , informed consent is required when : Data are collected from research participants through any form of communication , interaction , or intervention . Behaviour of research participants occurs in a private context where an individual can reasonably expect that no observation or reporting is taking place , except when researchers do research ` in public places or use publicly available information about individuals -LRB- e.g. naturalistic observations in public places , analysis of public records , or archival research -RRB- ' -LSB- 33 -RSB- . The question therefore arises of whether researchers analysing newsgroup postings enter a ` public place ' , or whether the space they invade is perceived as private . In the context of research , the expectation of the individual -LRB- whether he/she can reasonably expect that no observation is taking place -RRB- is crucial . Different Internet services have different levels of perceived privacy -LRB- in decreasing order of privacy : private e-mail ; chat rooms ; mailing lists ; newsgroups ; Web sites -RRB- . The perceived level of privacy is a function of the number of participants , but also depends on other factors such as group norms established by the community to be studied . For example , in a controversial paper , Finn studied a virtual self-support group where the moderator was actively discouraging interested professionals who were not sexual abuse survivors from joining the group -LSB- 34 -RSB- . In those cases , obtaining informed consent -LRB- or seeking an ethical waiver , if the research could not practicably be carried out were informed consent to be required -RRB- is mandatory . In practice , obtaining informed consent , especially for passive research methods , is difficult , as researchers usually can not post an announcement to a mailing list or newsgroup saying that it will be monitored and analysed for the next few months , as this may greatly influence or even spoil the results , and because the mere posting of such a request may disrupt the community , and therefore be considered unethical . Researchers should therefore first obtain consent from a group moderator in order to explore whether even a request for permission is felt to be disruptive to the group process . If the moderator or person responsible for the list has no objections , one may then post a message to a newsgroup or mailing list explaining the purpose of the research , explaining that one will observe the community , assuring all participants of anonymity , and giving them the opportunity to withdraw from the newsgroup or mailing list or to exclude themselves from the study by writing to the researcher . The fundamental problem is that this may influence the communication process and may even destroy the community . Besides , participants who later join the group need to get the same information . An alternative would be to analyse the communication retrospectively and to write individual e-mails to all participants whose comments were to be analysed or quoted , asking for permission to use them ; this technique has been used by Sharf -LSB- 35 -RSB- . In any case , researchers should make themselves familiar with the virtual community they are approaching ; i.e. read the messages in a newsgroup for some time -LRB- ` lurking ' -RRB- . Under no circumstances should researchers blindly spam -LRB- p. 31 -RRB- or cross-post requests for research participation to various newsgroups . Informed consent may also play a role when researchers report aggregate -LRB- collated and hence anonymous -RRB- data on usage patterns , such as a log-file analysis -LRB- reporting data on what Web sites have been accessed by a population -RRB- . Crucial here is an appropriate privacy statement stating that these data may be analysed and reported in aggregate -LSB- 28 -RSB- . Note that aggregate data are exempt from the registration requirements of the UK 's Data Protection Act of 1998 . In conducting surveys researchers may obtain informed consent by declaring the purpose of the study ; disclosing which institutions are behind the study ; explaining how privacy will be assured ; and detailing with whom data will be shared and how it will be reported , before participants complete the questionnaire . When reporting results , it is obvious that the total anonymity of research participants needs to be maintained . Researchers have to keep in mind that , by the very process of quoting the exact words of a newsgroup or mailing list participant , the confidentiality of the participant may already be broken as Internet search engines may be able to retrieve the original message , including the e-mail address of the sender . It is essential , therefore , to ask participants whether they agree to be quoted whenever there may be a retrievable archive , pointing out the risk that they may be identifiable . Problems can also potentially arise from just citing the name of the community -LRB- e.g. of a newsgroup -RRB- , which may damage the community being studied . Finding methods , protocols , and instruments For laboratory ` bench work ' , researchers often need a protocol for a specific assay method . In addition to the possibility of searching literature databases , there are also specialized services on the Web that can assist in this research , such as MethodsFinder and the ` Technical tips online ' database at BioMedNet : MethodsFinder -LRB- BIOSIS -RRB- : http://www.methodsfinder.org/ BioMedNet : http://www.bmn.com/ Sometimes asking a specific question on the right newsgroup or mailing list is also very effective . Clinical researchers may be more interested in instruments to measure patient outcomes.An excellent guide to selecting quality-of-life instruments is the Quality of Life Instruments Database at the Mapi Research Institute : http://www.qolid.org/ Online statistical analysis tools are available at the Simple Interactive Statistical Analysis -LRB- SISA -RRB- Web site , while background information is available within the online book Statistics at square one : SISA -LRB- Daan Uitenbroek -RRB- : http://home.clara.net/sisa/ Statistics at square one -LRB- British Medical Journal Publishing Group -RRB- : http://www.bmj.com/collections/statsbk/ Protocols of clinical trials , which may be useful for researchers developing their own protocols , can be found in some of the clinical trial databases available on the Web , as described below . Clinical trials and the Web The Web is being used to assist in the identification and conduction of clinical trials . Identifying trials To prevent unintended duplication of clinical research , detect underreporting of research , and ease the work of systemic reviewing , it has been suggested that we should prospectively register clinical trials -LSB- 36-39 -RSB- . It is , however , unlikely that there will ever be one complete centralized multinational database . Instead , multiple resources set up by numerous different organizations will exist -LSB- 40 -RSB- . Internet technology will play a central role in linking these databases and making this information available to researchers and patients . Some scenarios in which a search of trial databases may be useful : A researcher wants to conduct a randomized controlled trial and wants to know whether anyone else is already running one on the same topic . A physician has a patient who is asking about available trials . A patient is looking for ongoing trials . A researcher is looking for possible participants for his trial . A researcher doing a systematic review is looking for unpublished trials . Information about ongoing and completed clinical trials is increasingly being published on the Internet , and searches on the Web may be a useful means of complementing traditional bibliographic searches if authors of systematic reviews wish to find ongoing or unpublished trials -LSB- 41 -RSB- . Researchers use their personal or department home pages to announce their interest in a certain research area or to recruit patients -LSB- 42 -RSB- . Journals like The Lancet have begun to publish research protocols on their Web site -LSB- 43 -RSB- , and more and more researchers will also publish ` pre-prints ' -LRB- p. 239 -RRB- of their findings on the Web -LSB- 44 -RSB- . Consumers and patient organizations also have an interest in disseminating information about ongoing trials ; e.g. the National Alliance of Breast Cancer Organizations : http://www.nabco.org/ Government and funding agencies react to this need by establishing trial databases for consumers ; e.g. the US National Institutes of Health searchable database -LSB- 45 -RSB- : http://ClinicalTrials.gov Commercial enterprises also help researchers to recruit patients , or help patients to find clinical trials . For example : CenterWatch Clinical Trials Listing Service -LRB- CenterWatch , Inc. -RRB- : http://www.centerwatch.com/ ClinicalTrialFinder.com -LRB- Clinical Data Technologies Ltd -RRB- : http://www.clinicaltrialfinder.com/ Current Controlled Trials -LRB- BioMed Central -RRB- : http://www.controlled-trials.com Pharmaceutical companies and industry associations have likewise begun to recognize that openness and access to information on clinical trials and new drug developments can improve patient care and are part of social responsibility -LSB- 46 -RSB- . For example : Clinical Trials Register -LRB- GlaxoSmithKline -RRB- : http://ctr.glaxowellcome.co.uk/ Search for Cures -LRB- Pharmaceutical Research and Manufacturers of America -RRB- : http://www.phrma.org/searchcures/ Finally , information or databases on ongoing clinical trials can often also be found on disease-specific sites . For example : Canadian HIV Trials Network : http://www.hivnet.ubc.ca/ctn.html CancerNet -LRB- National Cancer Institute -RRB- : http://cancernet.nci.nih.gov/ Conducting trials on the Web The Web is increasingly being used in the course of conducting large-scale multi-centre clinical trials -LRB- e.g. for remote randomization and data entry -RRB- , and in the distribution of information on trial progress or protocols -LSB- 47,48 -RSB- . Trial centres may enter patient data using Java applets -LRB- see Glossary -RRB- that encrypt data and send it to the data centre via the Internet -LSB- 49-52 -RSB- , where the data are stored and randomized , returning for example a study number and randomization information . Pre-publishing and publishing research Traditional publication is a well-defined event , whereas ` publication ' in the electronic age is much more of a continuum -LSB- 53 -RSB- , reflecting and occurring during the entire research process from hypothesis formulation to data gathering , interpretation , and the presentation and discussion of the final results . In order to distinguish online collaborative ` work in progress ' from ` final ' peer-reviewed publication we may term the former ` Type 1 ' and the latter ` Type 2 ' electronic publication -LSB- 54 -RSB- . Here , peer review is not the distinguishing characteristic : in Type 1 publication a ` post-publication ' peer review process takes place . Type 2 publication will ordinarily take place in online journals . The following scenarios illustrate how researchers might use Type 1 electronic publication on the Internet : Sending and discussing preliminary results on mailing lists . Publishing drafts of scientific papers on pre-print/e-print sites -LRB- p. 239 -RRB- in order to solicit comments and to improve the manuscript . Publishing data and information in databases ; e.g. nucleotide sequences in the EMBL/Genbank databases . Publishing clinical trial protocols and raw data in a ` trial bank ' -LSB- 55 -RSB- . Current awareness services Electronic editions of paper journals and ` stand alone ' e-journals typically offer subscriptions to ` TOC alerts ' , where users receive a table of contents by e-mail as soon as a new issue appears.The more sophisticated systems allow users to specify their interests using a controlled vocabulary , enabling the system to screen each newly published article for certain keywords or citations . Examples of current awareness services include : Customised @lerts -LRB- British Medical Journal -RRB- : http://bmj.com/cgi/customalert/ JournAlert -LRB- Doctors.net.uk -RRB- : http://www.doctors.net.uk/ Journal Watch -LRB- Massachusetts Medical Society -RRB- : http://www.jwatch.org/

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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O B I O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O 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Factors Affecting Morbidity and Mortality of Roux-en-Y Gastric Bypass for Clinically Severe Obesity : An Analysis of 1,000 Consecutive Open Cases by a Single Surgeon Introduction Determinants of perioperative risk for RYGB are not well defined . Introduction Obesity is currently the number one public health problem in the United States , affecting one-third of all Americans -LRB- http : / www.surgeongeneral.gov/topics/obesity -RRB- . Approximately 5 to 8 % have clinically severe or morbid obesity and are candidates for bariatric surgery . This obesity epidemic has been accompanied by a geometric rise in the number of bariatric surgical procedures . The American Society for Bariatric Surgery -LRB- ASBS -RRB- estimates that the number of bariatric surgery procedures has increased from approximately 20,000 in 1996 to over 140,000 in 2004 -LRB- http://www.asbs.org -RRB- . During this period , membership in the ASBS has also increased fivefold , suggesting that many more surgeons are performing these procedures . The most common bariatric procedure performed in the United States is Roux-en-Y gastric bypass -LRB- RYGB -RRB- .1 The explosive growth of bariatric surgery has garnered much attention in the media , with much speculation about the risks , both short - and long-term , of RYGB . Unfortunately , to date , little information from large series is available concerning the operative mortality of RYGB and those factors that predict mortality . In 2002 , Livingston et al. 2 reported an operative mortality of 1.3 % in 1,067 patients after open RYGB and found that only age over 55 years correlated with perioperative mortality . More recently , Fernandez et al. 3 analyzed their patient cohort of 1,431 patients having open RYGB and found a 1.9 % mortality , which was associated with age , weight , longer limb gastric bypass , and the occurrence of a leak or pulmonary embolism . This report is a multivariate analysis of preoperative mortality and morbidity in 1,000 consecutive open RYGBs performed over a 5-year period by a single surgeon -LRB- LF -RRB- in at a single institution . Materials and Methods Bariatric Surgery Program The bariatric surgery program at St. Luke 's -- Roosevelt Hospital Center in New York City was initiated in April 1999 and the first operation performed in June 1999 . The basis of this report consists of 1,000 consecutive open RYGBs -LRB- primary cases and revisions -RRB- performed by a single surgeon , LF , between June 1999 and June 2004 . Clinical Protocol and Surgical Technique All patients were evaluated preoperatively and met generally accepted criteria outlined by the NIH at its Consensus Development Conference on Gastrointestinal Surgery for Severe Obesity .4 In addition , all patients were routinely evaluated by a registered dietitian experienced in the treatment of obesity . Mental health and other specialty consultations were only obtained if they were felt to be clinically indicated or were required by an insurance carrier . All patients were evaluated by an attending anesthesiologist before surgery.Routine preoperative studies included : electrocardiogram , chest x-ray , gallbladder ultrasonography , serum electrolytes , glucose , HbA1c , calcium , albumin , lipid profile , liver function tests , complete blood count , platelets , prothrombin time , partial thromboplastin time , INR , and urinalysis . Over time , additional preoperative studies , including serum insulin , iron , ferritin , vitamin B12 , 25-OH vitamin D , and thiamine -LRB- vitamin B1 -RRB- were added.RYGB was performed in a standard fashion with the following common elements : -LRB- 1 -RRB- open technique ; -LRB- 2 -RRB- 20 -- 30 ml pouch , nondivided stomach , TA 90B -LRB- US Surgical , Norwalk , CT , USA -RRB- applied twice ; -LRB- 3 -RRB- hand-sewn two-layer retrocolic , antegastric gastrojejunostomy , 12 mm in length , tested with methylene blue under pressure intraoperatively ; -LRB- 4 -RRB- side-to-side , functional end-to-end jejunojejunostomy with dispSAble GIA -LRB- US Surgical -RRB- or LC -LRB- Ethicon Endosurgery , Sommerville , NJ , USA -RRB- 75 mm staplers , and TA55 -LRB- US Surgical -RRB- or TX 60 -LRB- Ethicon Endosurgery -RRB- staplers and routinely oversewn with 3 -- 0 silk Lembert sutures . The biliopancreatic limb-length measured 75 cm along the antimesenteric border for patients with BMI less than 50 and 150 cm for patients with BMI greater than or equal to 50 . The Roux or alimentary limb-length was 150 cm in all patients . For the initial 14 cases , the stomach was divided using the GIA-100 stapler . This technique was abandoned and switched to the nondivided stomach after a stapler malfunction led to a leak.Closed suction drains were placed in all revisions , patients with BMI > 55 , or if clinically indicated -LRB- e.g. , identification of an intraoperative leak , technically difficult anastomosis -RRB- . Drains were removed as clinically indicated . Fascia was closed with a running looped # 1 PDS -LRB- Ethicon , Sommerville -RRB- and infiltrated with 0.25 % bupivacaine . The subcutaneous space was drained with a # 10 Jackson -- Pratt drain and the skin was closed with a running subcuticular stitch.The gallbladder was removed if gallstones were documented by preoperative ultrasound . Incisional or umbilical hernias were primarily repaired if encountered , oftentimes through a separate periumbilical incision.Invasive monitoring was not used routinely and Foley catheters were only placed if patients required invasive hemodynamic monitoring or in the case of revisions or when patients had multiple prior abdominal operations . Nasogastric tubes were left in placed as clinically indicated -LRB- intraoperative leak identified -RRB- or in patients with BMI > 55 . All patients received perioperative antibiotics for 24 h , cefazolin -LRB- 2 g intravenously every 8 h for three total doses -RRB- or clindamycin -LRB- 900 mg intravenously every 6 h for four doses -RRB- . Prophylaxis against deep vein thrombosis consisted of 5,000 units of unfractionated heparin administered subcutaneously every 8 h and pneumatic compression stockings until ambulatory . All patients were given a PCA pump -LRB- patient-controlled analgesia -RRB- for pain . Patients were routinely cared for on a regular surgical floor , equipped for severely obese patients . Patients with significant SA or documented CAD were usually observed in the recovery room overnight , and only rarely admitted to the intensive care unit . On the morning of postoperative day 1 , patients were routinely studied with gastrograffin upper-GI studies . If no leak was identified , they were given liquids for lunch and advanced to soft food -LRB- yogurt , apple sauce , and cottage cheese -RRB- for dinner and switched to oral pain medications . Drains were usually removed before discharge . Patients were discharged on POD # 2 or # 3 as indicated with the following medications : a codeine-derivative for pain , prenatal vitamins , iron polysaccharide , calcium citrate , ursodeoxycholic acid , if the gallbladder was present.After hospital discharge , patients were scheduled to be seen at 2 and 8 weeks , 6 , 12 , 18 , 24 months , and yearly thereafter . All routine follow-up appointments included nutritional counseling and those after 2 weeks included laboratory studies -LSB- serum electrolytes , glucose , HbA1c , calcium , albumin , lipid profile , liver function tests , complete blood count , platelets , serum insulin , iron , ferritin , vitamin B12 , 25-OH vitamin D , and thiamine -LRB- vitamin B1 -RRB- -RSB- . Follow-up was 74 % at 1 year , 68 % at 2 years , 59 % at 3 years , 53 % at 4 years , and 48 % at 5 years . Clinical Data and Data Analysis Clinical and laboratory data were PC-based database prospectively maintained since the program 's inception in 1999 . Data collected included : age , sex , height weight , BMI , race/ethnicity , payer status , obesity-related comorbidities , operative procedure , duration of stay , mortality , major complications , and death . Complications were classified as systemic -LRB- prolonged intubation , deep venous thrombosis , pulmonary embolism , and myocardial infarction/fatal arrhythmia -RRB- or technical -LRB- incisional hernia , intestinal obstruction , leak/perforation , dehiscence , GI bleeding , anastomotic stricture , and anastomotic ulcer -RRB- . Deaths were analyzed with respect to BMI , demographics , comorbidities , and complications.Superficial wound infections were not included ; the incidence of urinary tract infections was not tracked . Nutritional complications were not evaluated because all patients were routinely maintained on vitamins , iron , and calcium supplements postoperatively ; it would be impossible to determine the true incidence of any of these nutritional deficiencies.Univariate analyses and logistic regression with SPSS 11.0 were used to determine significance . Results The population consisted of 854 women and 146 men . Their demographic characteristics are summarized in Table 1 . The prevalence of obesity-related comorbid conditions is shown in Table 2 . Table 1Demographic Characteristics by Sex and Race WomenMenTotalp-ValueAge -LRB- years -RRB- 38 ± 1.0 -LRB- 15 -- 73 -RRB- 40 ± 11.9 -LRB- 15 -- 65 -RRB- 38 ± 11.17 -LRB- 15 -- 73 -RRB- 0.064 Weight -LRB- kg -RRB- 134 ± 27 -LRB- 84 -- 263 -RRB- 170 ± 43 -LRB- 81 -- 345 -RRB- 139 ± 33 -LRB- 82 -- 345 -RRB- < 0.01 BMI -LRB- kg/m2 -RRB- 51 ± 10 -LRB- 35 -- 1,000 -RRB- 55 ± 13 -LRB- 24 -- 116 -RRB- 51 ± 10 -LRB- 24 -- 116 -RRB- < 0.01 Caucasian -LRB- 28 % -RRB- 238/853 -LRB- 53 % -RRB- 78/14732 % < 0.01 African -- American -LRB- 30 % -RRB- 253/853 -LRB- 20 % -RRB- 29/14728 % 0.01 Hispanic -LRB- 42 % -RRB- 358/853 -LRB- 27 % -RRB- 40/14740 % < 0.01 Other -LRB- 0.5 % -RRB- 4/853 -LRB- 0 % -RRB- 0/1470 .4 % 0.41 Table 2Prevalence of Obesity-Related Comorbid Conditions by Sex Women -LRB- N = 853 -RRB- -LRB- % -RRB- Men -LRB- N = 147 -RRB- -LRB- % -RRB- Total -LRB- % -RRB- p-ValueType II diabetes mellitus177 -LRB- 21 -RRB- 54 -LRB- 37 -RRB- 23 < 0.01 Hypertension310 -LRB- 36 -RRB- 79 -LRB- 54 -RRB- 39 < 0.01 CAD/CHF29 -LRB- 3 -RRB- 26 -LRB- 18 -RRB- 6 < 0.01 Dyslipidemia376 -LRB- 44 -RRB- 80 -LRB- 54 -RRB- 470.02 Sleep apnea172 -LRB- 20 -RRB- 63 -LRB- 43 -RRB- 24 < 0.01 Asthma135 -LRB- 16 -RRB- 16 -LRB- 11 -RRB- 150.12 Dyspnea on exertion811 -LRB- 95 -RRB- 127 -LRB- 86 -RRB- 48 < 0.01 GERD513 -LRB- 60 -RRB- 77 -LRB- 52 -RRB- 590.08 Osteoarthritis791 -LRB- 93 -RRB- 126 -LRB- 87 -RRB- 92 < 0.01 Urinary stress incontinence430 / -LRB- 50 -RRB- 5 -LRB- 3 -RRB- 44 < 0.01 Irregular menses276 -LRB- 32 -RRB- NA32NACAD/CHF coronary artery disease/congestive heart failure , GERD gastroesophageal reflux disease The most common comorbidites encountered were dyspnea on exertion -LRB- 94 % -RRB- , joint pain/arthritis -LRB- 92 % -RRB- , and gastroesophageal reflux disease -LRB- 59 % -RRB- . The comorbidites typically associated with systemic disease included hypertension -LRB- HTN , 39 % -RRB- , obstructive sleep apnea -LRB- SA , 24 % -RRB- , dyslipidemia -LRB- 46 % -RRB- , and asthma -LRB- 15 % -RRB- . Approximately 23 % of the patient population suffered from type II diabetes mellitus -LRB- DM -RRB- . At time of initial evaluation , 13.0 % of this diabetic patient subset had a prior history of insulin-dependent DM , 57.6 % had noninsulin dependent DM , and 23 % had a previous diagnosis of DM intermittently controlled on diet or were newly diagnosed with DM during their preoperative evaluation . Six percent of the patient population had angiographically documented histories of coronary artery disease -LRB- CAD -RRB- but were deemed suitable risk by their respective specialists . Procedures and Duration of Hospital Stay There were 966 primary RYGB and 34 revisions of failed bariatric procedures -LRB- 21 -- VBG , 5 -- RYGB , 8 -- other ; all performed at outside institutions -RRB- to RYGB . The median length of stay for primary procedures was 2.4 days compared to 3.7 days for revisions . Average -LRB- LOS -RRB- for all patients having primary RYGB was 3.8 days with 87 % of the group leaving in 3 days or less . Complications Overall , 91 % of the procedures were without systemic or technical complications.The incidence of complications in relation to BMI is summarized in Table 3 . Overall , systemic complications occurred rarely , but did not usually correlate with BMI . The most common technical complications were incisional hernia -LRB- 3.5 % -RRB- , intestinal obstruction -LRB- 1.9 % -RRB- , and leak/perforation -LRB- 1.6 % -RRB- . Table 3Incidence of Complications after RYGBComplicationBMI < 50 -LRB- % -RRB- -LRB- N = 481 -RRB- BMI > 50 -LRB- % -RRB- -LRB- N = 515 -RRB- Total -LRB- % -RRB- p-ValueSystemic complicationsProlonged intubation3 -LRB- 0.6 -RRB- 8 -LRB- 1.5 -RRB- 1.10.16 -LRB- NS -RRB- Deep venous thrombosis0 -LRB- 0 -RRB- 2 -LRB- 0.4 -RRB- 0.2 NSPulmonary embolism0 -LRB- 0 -RRB- 3 -LRB- 0.6 -RRB- 0.3 NSMI/fatal arrhythmia1 -LRB- 0.2 -RRB- 1 -LRB- 0.2 -RRB- 0.2 NSTechnical complicationsIncisional hernia10 -LRB- 2.1 -RRB- 25 -LRB- 4.8 -RRB- 3.50.019 Intestinal obstruction10 -LRB- 2.1 -RRB- 9 -LRB- 1.7 -RRB- 1.9 NSLeak7 -LRB- 1.5 -RRB- 9 -LRB- 1.9 -RRB- 1.6 NSDehiscence2 -LRB- 0.4 -RRB- 2 -LRB- 0.4 -RRB- 0.4 NSGI bleeding requiring transfusion3 -LRB- 0.6 -RRB- 6 -LRB- 1.2 -RRB- 0.9 NSAnastomotic ulcer2 -LRB- 0.4 -RRB- 0 -LRB- 0 -RRB- 0.2 NSAnastomotic Stricture6 -LRB- 1.2 -RRB- 2 -LRB- 0.4 -RRB- 0.8 NSDeath4 -LRB- 0.8 -RRB- 11 -LRB- 2.1 -RRB- 1.5.03Thirty-one patients -LRB- 3.1 % -RRB- required reoperation within 30 days of the original procedure . The indications for reoperation within 30 days were leak/perforation -LRB- 11 -RRB- , intestinal obstruction -LRB- 9 -RRB- , bleeding -LRB- 4 -RRB- , rule-out leak -LRB- 2 -RRB- , dehiscence -LRB- 4 -RRB- , and subphrenic abscess -LRB- 1 -RRB- . Indications for late operations -LRB- > 30 days postoperatively -RRB- included incisional hernia repair in 35 patients , intestinal obstruction in 10 patients , and repair of leaks/perforations in five patients who were experiencing ongoing postoperative complications . No patients required reoperation for refractory anastomatic stricture or ulcer . One patient developed a gastrogastric fistula after repair of an early leak , which was treated expectantly since it was clinically insignificant . No late gastrogastric fistulae were identified . Deaths Thirty-day mortality was 1.2 % . Overall mortality attributable to surgery was 1.5 % . Patients with late deaths due to unrelated events , such as motor vehicle accidents -LRB- N = 2 -RRB- or drug overdoses -LRB- N = 1 -RRB- , were excluded and not classified as mortalities in the analysis . Mortality correlated with BMI , with four -LRB- 0.8 % -RRB- patients having a BMI < 50 dying compared to 11 -LRB- 2.1 % -RRB- patients with BMI ≥ 50 -LRB- p = 0.03 -RRB- -LRB- Table 3 -RRB- . Causes of death after RYGB , along with their timing and relationship to BMI are shown in Table 4 . Two patients died of fatal arrhythmias on POD # 3 and # 4 . Both were males , ages 48 and 54 , with BMIs > 50 , DM , CAD , HTN , and SA . Autopsies were performed in both instances and no other precipitating factors were identified . One patient , a 43-year-old woman with a BMI 59 , died of a pulmonary embolism -LRB- identified at autopsy -RRB- at home after 2 weeks . Table 4Causes of Early and Late Deaths Related to BMICause of deathEarly -LRB- < 30 days -RRB- -LRB- N = 11 -RRB- Late -LRB- > 30 days -RRB- -LRB- N = 4 -RRB- BMI < 50BMI ≥ 50BMI < 50BMI ≥ 50MI/arrhythmia0200Pulmonary/PE0100MSOF 20 leak1212MSOF 20 bowel obstruction0100MSOF cause unknown1100Bleeding complications1200PE Pulmonary embolism , MSOF multisystem organ failureSix patients died from MSOF after postoperative leaks , three from the gastrojejunostomy and three from perforations of the distal small bowel within the common channel . Of these , four occurred and were diagnosed within 48 h of the initial RYGB and all were emergently explored . All four developed MSOF and expired between 14 and 211 days postoperatively . Of the remaining two deaths , one patient , 46-year-old woman with a BMI 79 and a history of chronic ventilator dependence due to a paralyzed left hemidiaphragm on chronic steroid therapy developed a late leak and multiple intestinal fistulae and eventually succumbed to MSOF . The other patient , a 43-year-old woman , BMI 43 , had undergone a laparoscopic RYGB at another institution that was complicated by a strangulated internal hernia , massive intestinal gangrene , and short-bowel syndrome . She underwent a reversal of her RYGB with reconstruction of her GI tract , but developed multiple small bowel fistulae 2 weeks postoperatively and died of MSOF several months later.Three patients died from a severe systemic inflammatory response syndrome -LRB- SIRS -RRB- with MSOF accompanied by extremely high fevers , without any identifiable source . One was a 70-year-old woman with BMI 68 underwent reexploration for an early postoperative small bowel obstruction . The others were a 54-year-old woman with a BMI 47 , DM , HTN , and SA and a 37-year-old male with BMI 94 and severe SA and HTN . Each developed SIRS and MSOF with temperatures of 105 -- 107 °F and hyperdynamic circulations . No intraabdominal or other sources were identified despite numerous cultures and radiologic studies.Three patients died of bleeding complications . A 43-year-old woman with a BMI 48 suffered progressive hypotension and tachycardia in the recovery room postoperatively . These symptoms were initially addressed with rehydration allowing the patient 's hematocrit to fall to a level where hypovolemic shock and resulting coagulopathy obscured efforts to surgically control or identify a single source . A 31-year-old woman with a BMI 50 was returned to the OR 4 h postoperatively for control of bleeding from the small bowel mesentery . After this second procedure , she developed SIRS , temperatures of 106 °F , and MSOF , with no identifiable source of sepsis . A 54-year-old male with a BMI 56 and a history of HTN , CAD , and chronic atrial fibrillation suffered a postoperative myocardial infarction and developed a coagulopathy complicated by a massive intraspenic hematoma after restarting coumadin , which rapidly progressed to anuria and MSOF . Attempts to reverse his anticoagulation and control the bleeding angiographically were unsuccessful.The necessity for reoperation within 30 days of the original procedure was particularly ominous . Overall , the incidence of death after a second operative procedure within 30 days was 9/31 -LRB- 29 % -RRB- . Two of the 16 patients with a BMI < 50 who required reoperation within 30 days died -LRB- 12.5 % -RRB- compared to 7 out of 15 patients with BMI ≥ 50 -LRB- 47 % p = 0.03 -RRB- . This is similar to the mortality for the entire series where 0.8 % for patients with a BMI < 50 died compared to 2.1 % for patients with BMI ≥ 50 -LRB- p = 0.03 -RRB- . However , among those 15 patients classified as operative deaths for the entire series , 9 -LRB- 60 % -RRB- died after their second operative procedure.Logistic regression demonstrated that CAD -LSB- LR 7.5 p < 0.01 -LRB- 95 % CI 2.2 to 25.3 -RRB- -RSB- , and SA -LSB- LR 3.3 p = 0.03 -LRB- 95 % CI 1.1 to 10.1 -RRB- -RSB- , followed by age -LSB- LR 1.06 p = 0.042 -LRB- 95 % CI 1.00 to 1.12 -RRB- -RSB- , were risk factors for death in all patients -LRB- Table 5 -RRB- . Although a small sample set , 12.7 % of patients with CAD died -LRB- 7/55 -RRB- and 29 % of patients with BMI > 50 and CAD and SA died . Table 5Logistic Regression Evaluation of Patient Comorbidity as Predictors of Mortality p-ValueRelative Risk95 % Confidence IntervalAge0 .0421.0591.002 -- 1.120 BMI0 .1301.0250.993 -- 1.058 Female0 .6120.7290.215 -- 2.474 DM0 .8520.8890.259 -- 3.054 HTN0 .2572.0850.585 -- 7.438 CAD0 .0017.4462.195 -- 25.258 Dyslipidemia0 .0990.3590.106 -- 1.211 Asthma0 .0703.0650.913 -- 10.293 SA0 .0333.3421.104 -- 10.115 SOB0 .6930.6440.073 -- 5.725 Although the average BMI of males was slightly greater than that of females -LRB- 55.2 vs 51.2 kg/m2 , p < 0.01 -RRB- , the two populations also differed in characteristics other than BMI . The male population had a significantly significant greater prevalence of DM , HTN , CAD , dyslipidemia , and SA . Females had a greater prevalence of pulmonary comorbidities , including asthma and dyspnea on exertion -LRB- Table 2 -RRB- . When logistic regression was performed specific to the subsets of sex , males with angiographically demonstrated CAD were 30 times more likely to die -LSB- LR 30.1 p = 0.028 -LRB- 95 % CI 1.4 to 631.4 -RRB- -RSB- . Logistic regression did not identify CAD as a significant predictor when the analysis was limited to women . Predictors of death for women include age -LSB- LR 1.07 p = 0.033 -LRB- 95 % CI 1.0 to 1.14 -RRB- and SA -LSB- LR 4.1 p = 0.040 -LRB- 95 % CI 1.07 to 16.2 -RRB- -RSB- . Logistic regression was repeated specific to race . When limited to Caucasian patients only , Caucasians with CAD were 58 times more likely to die -LSB- LR 58.8 p < 0.01 -LRB- 95 % CI 4.8 to 716.9 -RRB- -RSB- than those Caucasians without CAD . Increasing BMI was also significant among Caucasians . -LSB- LR 1.08 p = 0.02 -LRB- 95 % CI 1.01 to 1.16 -RRB- -RSB- . Evaluation of African -- American patients demonstrated that only SA was significant -LSB- LR 19.1 p = 0.03 -LRB- 95 % CI 1.29 to 282.8 -RRB- -RSB- . Regression of the Hispanic population did not identify a specific factor . One-way ANOVA did not demonstrate any significant differences in prevalence of death or CAD between the three racial groups for the entire population or specific to sex.Hispanic patients had significantly less SA than either the Caucasian or African -- American patients -LRB- 18.1 vs 25.6 and 27.4 % , respectively -LRB- p = 0.01 -RRB- -RRB- . When examined specifically in relation to sex , there were no differences among prevalence of SA in the males . African -- American women , however , had the greatest prevalence of SA -LRB- 26.4 % -RRB- compared to Caucasian -LRB- 18.9 % -RRB- and Hispanic -LRB- 15.7 % -RRB- women -LRB- p < 0.01 -RRB- . Discussion The tremendous growth of bariatric surgery over the past several years has spawned much interest in its complications and mortality , first in the media , but most recently in the public health arena as well . Health and malpractice insurance carriers as well as governmental agencies and professional societies are evaluating the risks of bariatric surgery and the surgeons that perform it . In several states , insurance companies have stopped covering bariatric surgery at the same time that the Centers for Medicare and Medicaid Services have approved coverage for them . Several malpractice carriers have stopped issuing policies for surgeons performing bariatric procedures while others are categorizing bariatric surgery as a high-risk subspecialty area , similar to obstetrics and neurosurgery , and increasing premiums accordingly . In each of these instances , the overriding fear or consideration appears to be that the risks associated with bariatric surgery are excessively high . Much of the information being utilized in this regard has come form series utilizing pooled data from multiple smaller series or government databases .1,5 -- 9 Buchwald et al. 5 performed a metaanalysis of 16,944 patients which included 7,074 patients that underwent gastric bypass -LRB- open and laparoscopic -RRB- in 44 studies with a 30-day mortality rate of 0.5 % . Several authors have reported that complication rates of bariatric surgery were inversely correlated with case loads , reporting mortality rates of in the range of 0.1 -- 0.5 % for surgeons more than 100 or 150 cases per year .6 -- 8 Flum et al. 9 recently reported 30 - and 90-day mortality rates of 2.0 and 2.8 % , respectively in Medicare beneficiaries having bariatric surgery , with men having higher rates than women and those over 65 years of age having higher rates than those younger than 65 . Many of these series lack data concerning BMI and comorbidities , making risk assessment difficult or impossible . In one large series from a single-center , Christou et al. 10 reported a 30-day mortality of 0.4 % in 1,035 patients undergoing RYGB , of whom 820 had open RYGB . No details about preexisting comorbidities or perioperative complications were given . The results of these pooled series differ from those in several large series of open gastric bypasses2 ,3,11 . Livingston et al. 2 reported an operative mortality of 1.3 % in 1,067 patients after open RYGB . In his series , mean BMI was 53.6 kg/m2 , mean age 42.3 years , and the incidence of comorbidities was diabetes -LRB- 23 % -RRB- , hypertension -LRB- 48 % -RRB- , and sleep apnea -LRB- 39 % -RRB- . Only male sex was predictive of severe life-threatening complications ; mortality in patients over 55 years was significantly greater than in patients under 55 -LRB- 3.5 vs 1.1 % , p < 0.05 -RRB- . More recently , Fernandez et al. 3 analyzed their patient cohort of 1,431 patients having open RYGB and found a 1.9 % mortality , which was associated with age , weight , longer limb gastric bypass , and the occurrence of a leak or pulmonary embolism . In that series , the mean BMI was 53.3 , mean age 40.7 years , and incidence of serious comorbidities was diabetes -LRB- 19.5 % -RRB- , hypertension -LRB- 51 % -RRB- , and sleep apnea -LRB- 33 % -RRB- . In both of these series , the BMI was higher , the patients were older and the incidence of serious comorbidities , such as diabetes , hypertension , dyslipidemia , and sleep apnea , higher . Pories et al. 11 reported a 1.5 % perioperative mortality rate , with 0.8 % dying of sepsis , 0.5 % dying of pulmonary embolism , and 0.2 % of an unknown cause . Additional information regarding the incidence of leaks , bowel obstructions and other complications was not reported as these were not the focus of the original paper . Similarly , in the present series , the 30-day mortality rate was 1.2 % in 1,000 patients with a mean BMI of 52 kg/m2 . The prevalence of preoperative comorbidities was comparable to the larger series -LRB- diabetes -- 23 % , hypertension -- 39 % , dyslipidemia -- 46 % , coronary artery disease/congestive heart failure -- 5.5 % , sleep apnea -- 23.5 % , and asthma -- 15 % -RRB- and generally higher than in the pooled series . The incidence of leaks and postoperative small bowel obstruction in our series was comparable to the other series . The incidence of pulmonary embolism was less than those reported , perhaps related to the use of both pneumatic compression stockings and subcutaneous heparin and early ambulation with a shorter length of stay . Although the incidence of incisional hernia in our series was low -LRB- 3.5 % -RRB- , this may well be affected by our suboptimal follow-up . Multisystem organ failure accounted for 11 deaths in our series -LRB- 73 % -RRB- . In six patients , this resulted from leaks or perforations ; in one it followed a bowel obstruction , in two it followed postoperative hemorrhage and in two patients , the cause was never determined . In each of these instances , the complication was identified early and appropriate treatment and supportive care instituted . In four of the patients , the clinical course of SIRS and MSOF was characterized by extremely high temperatures -LRB- > 105 °F -RRB- , with no apparent source ever identified . To our knowledge , this `` syndrome '' has not been reported , but may be due to the fact that the enormous adipose tissue stores in these patients may act as a `` metabolic sink '' , releasing cytokines and other mediators and perpetuating this extreme systemic inflammatory response . Two of the deaths were due to fatal arrhythmias , both in patients with known CAD , who were extensively evaluated preoperatively . The death due to pulmonary embolism occurred after discharge , even though the patient received prophylaxis with both heparin and pneumatic compression stockings in the hospital . The remaining death due to exsanguination was clearly preventable . Although males were significantly heavier and had higher BMIs than women , sex was not an independent predictor of morbidity . However , the presence of angiographically documented coronary artery disease was particularly ominous in men . Males with angiographically demonstrated CAD were 30 times more likely to die . In women , predictors of death included age and SA , but not CAD . With respect to race , Caucasian males with BMI > 50 and CAD were most likely to die , whereas SA was a predictor in African -- American men . There were no predictors in Hispanics . Despite the increased mortality in Caucasian males with CAD , these patients were not candidates for cardiac revascularization and extreme weight loss was the only intervention thought to make a beneficial health impact . Based upon our data and those of others2 ,3,11 , it appears that the risk of open RYGB is in the range of 1 -- 2 % . Risk appears to be adversely affected by increasing BMI and those factors with which it is often associated namely male sex and coronary artery disease . How this compares with the perioperative mortality after laparoscopic RYGB is still unclear because many series of patients having laparoscopic RYGB do not include patients with the highest BMIs , above 60 or 70 kg/m2 , or patients having revisional surgery . A perioperative mortality rate of 1.2 % after RYGB compares favorably with that after other common surgical procedures . For example , perioperative mortality after elective surgery for abdominal aortic aneurysms has been reported at 3.1 -- 4.7 % overall , 1.0 -- 2.7 % in patients under 65 years of age , and 3.5 -- 5.2 % in patients over 65 years of age .12 Using Medicare data adjusted for high volume surgeons , Birkmeyer et al. 13 reported perioperative mortality rates of 4.5 % for colectomy , 8.6 % for gastrectomy , 8.4 % for esophagectomy , 3.8 % for pancreatic resection , 4.0 % for pulmonary lobectomy , and 10.7 % for pneumonectomy . While it is true that all of these patients were over 65 years of age , the fact still remains that these perioperative mortality rates are all substantially greater than that after RYGB -LRB- even in Medicare recipients , as recently reported9 -RRB- and neither the public , the press , the insurance industry , or various state Departments of Health are appalled or alarmed , or calling for a moratorium on those procedures . This is not meant to suggest that every effort should not be made to lessen the risks of bariatric surgery and to improve operative mortality , but rather to inject some proportionality into the discussion . The importance of such careful analysis of bariatric surgical data , including its limitations , and the need to continue to offer bariatric surgery to those patients for whom it constitutes the best available treatment has recently been emphasized .14 In his 2004 PERSPECTIVE , Surgery for Severe Obesity , Steinbrook15 quotes Robert Brolin , MD , cautioning physicians and the public `` ... to reconcile the fact that the operation has a real mortality and it will continue to have a real mortality under the best of circumstances . Some of these patients are just profound operative risks for any kind of surgical intervention ... The sickest ones are the ones who benefit the most , but they are also the highest risk '' . Conclusion RYGB can be performed with acceptable perioperative morbidity in patients over a wide range of BMIs . Patients with BMI ≥ 50 have a higher morality for both initial operations and after reexploration . Age , coronary artery disease , and obstructive sleep apnea correlate with perioperative mortality . These three comorbidities were more prevalent in these patients and may contribute to this finding .

O O B O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O