bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Bayesian Approach to Estimate and Validate the False Negative Fraction in a Two-stage Multiple Screening Test
Authors: Ranyimbo A. O. , Held L. 
Published: March 2018

Summary

Objectives:
In estimating sensitivity and specificity of a diagnostic kit it is imperative that all study subjects are verified via a gold standard procedure. However the application of such a procedure to all the study subjects may not be feasible due to associated cost, risk and invasiveness. As a result only a part of the study subjects receive the definitive assessment. The accuracy of a diagnostic kit can also be expressed in terms of its error rates. Our first objective is to estimate the false negative fraction (FNF) under partial verification in a particular case of a two-stage multiple screening test using a beta-binomial model and a Bayesian logistic model. The second objective is to validate the two models in order to determine which fits the data better.

Methods:
We estimate the FNF from the above mentioned models using Bayesian approach. The validation of the models is based on their out-of-sample predictive capabilities.

Results:
For the bowel cancer data that was used in this study we found the median posterior estimate of the FNF, based on the beta-binomial model, to be 26.4% (95% credible interval: 0.123-0.650). The corresponding estimate based on the Bayesian logistic model was 23.3% (95% credible interval: 0.124-0.375). Validation results showed that the beta-binomial model gave slightly better predictions compared to the Bayesian logistic model.

Conclusions:
Estimation of the FNF can be done by adopting the Bayesian approach. Models fitted can be validated by comparing their performance in terms of their out-of-sample predicitve potential.
Prospective Molecular Epidemiological Study on Transmission of Pulmonary Tuberculosis and Migration (MuT Study)
Authors: Becher H. , Dreweck C. , Haas W. , Richter E. , Niemann S. , Junghanss T. , Bischof U. 
Published: March 2018

Summary

Introduction:
In Western Europe prevalence and incidence of tuberculosis in the indigenous population is declining and TB in migrants from high prevalence countries is becoming a major issue of TB control. Resulting changes in transmission patterns need to be investigated to adapt control strategies. The MuT (Migration and Tuberculosis) study a co-operation among federal and local public health services (ÖDG), the National Surveillance Center (RKI) and the University has been established in Baden-Wuerttemberg to address these issues.

Objectives:
The goal of this ongoing study is to determine the transmission dynamics of TB in Baden-Wuerttemberg. Here, we present the first set of data on TB cases and their contacts and discuss strategies to overcome arising difficulties.

Methods:
Prospective data collection of culture positive pulmonary tuberculosis cases and their contacts. Analysis of (1) routine data, (2) spatial data, (3) social interaction data, (4) molecular typing data, and (5) observational data of the implementation phase.

Results:
The study demonstrates the capability of the study consortium to identify clusters. It provides valuable insights into current case detection and case management procedures and shows ways to improve. A set of factors has been identified that (a) facilitate and (b) discourage study participation.

Conclusion:
Collaboration among federal and local public health services (ÖGD), National Surveillance Center (RKI) and the University is a promising approach to investigate and improve TB control. This model has potentials for other infectious disease control.
Interaction Effects and Population-attributable Risks for Smoking and Alcohol on Laryngeal Cancer and Its Subsites
Authors: Dietz A. , Becher H. , Ramroth H. 
Published: March 2018

Summary

Objectives:
To assess the joint effect of smoking and alcohol consumption on laryngeal risk on tumor subsites.

Methods:
Population-based case-control study in South-West Germany with 257 histologically confirmed cases (236 males, 21 females), age 37 to 80 years, and 769 population controls (702 males, 67 females), 1:3 frequency matched by age and sex.

Results:
Half of the tumors (50.6%) were glottic or subglottic, 17.5% were supraglottic. Due to advanced stage, the subsite of 31.9% of the tumors could not be determined clearly. There is a strong increase in risk with increasing tobacco consumption with an odds ratio (OR) of 59.8 (95% confidence interval (CI) 21.3-167.3) for heavy smoking (>80 packyears (py)), all cases combined. In comparison to current smokers, cancer risk is reduced for ex-smoking (>2 years) OR=0.36, 95% CI 0.24-0.53. The risks were higher for supraglottic than for glottic and sub-glottic tumors. The effect of alcohol is not as strong. A significantly increased odds ratio of 2.0, 95% CI (1.0-3.9) results for 75-100 g ethanol/day only for glottic and subglottic tumors. The OR rises from 2.2, 95% CI (1.1-4.3) for 100-150 g ethanol/day to 4.3, 95% CI (1.4-13.2) for more than 150 g ethanol/day (all models adjusted for education). The joint effect of smoking and alcohol results appears sub-multiplicative but super-additive. Almost 90% of the tumors can be attributed to both factors.

Conclusion:
Contrary to earlier investigations we observed a sub-multiplicative effect of smoking and alcohol. The risk for persons with both high alcohol and tobacco consumption is extremely high which indicates the importance of intervention.
Different Methods to Calculate Effect Estimates in Cross-sectional Studies
Authors: Taeger D. , Wellmann J. , Keil U. , Behrens T. 
Published: March 2018

Summary

Objectives:
According to results from the epidemiological literature, it can be expected that the prevalence odds ratio (POR) and the prevalence ratio (PR) differ with increasing disease prevalence. We illustrate different concepts to calculate these effect measures in cross-sectional studies and discuss their advantages and weaknesses, using actual data from the ISAAC Phase III cross-sectional survey in Münster, Germany.

Methods:
We analyzed data on the association between self-reported traffic density and wheeze and asthma by means of the POR, obtained from a logistic regression, and the PR, which was estimated from a log-linear binomial model and from different variants of a Poisson regression.

Results:
The analysis based on the less frequent disease, i.e. asthma with an overall prevalence of 7.8%, yielded similar results for all estimates. When wheezing with a prevalence of 17.5% was analyzed, the POR produced the highest estimates with the widest confidence intervals. While the point estimates were similar in the log-binomial model and Poisson regression, the latter showed wider confidence intervals. When we calculated the Poisson regression with robust variances, confidence intervals narrowed.

Conclusions:
Since cross-sectional studies often deal with frequent diseases, we encourage analyzing cross-sectional data based on log-linear binomial models, which is the ‘natural method’ for estimating prevalence ratios. If algorithms fail to converge, a useful alternative is to define appropriate starting values or, if models still do not converge, to calculate a Poisson regression with robust estimates to control for overestimation of errors in the binomial data.
Analysis of Proportions from Clustered Data with Missing Observations in a Matched-pair Design
Authors: Nevalainen J. , Schwenke C. 
Published: March 2018

Summary

Objectives:
Typically, methods for the estimation of differences in proportions from clustered data are based on complete cases with no missing information [1, 2]. In this paper we propose an extension to the method of Rao and Scott [3] and Obuchowski [2] to allow for the explicit computation of the variance of the estimator for the difference in presence of incomplete cases.

Methods:
We divided the full analysis set into a set of complete cases and a set of incomplete cases. The differences in proportions of correct diagnoses were estimated for each set by taking into consideration the clustering effect for both sets and the correlation between the procedures in the set with complete cases. Then the estimates of the two parts were combined by appropriate weights, which then allowed the explicit calculation of the variance. The performance of the extension as compared to the original method and generalized estimation equations model (GEEs) was examined by simulations.

Results:
The results of the examples suggest that the extended approach is superior to the complete-case method and is therefore appropriate when all data are to be used. In comparison to GEEs, the extended method appears to be slightly inferior, when the number of observations per patient is high, but of similar efficiency with a low number of observations per patient.

Conclusions:
With the extension of the method by Rao and Scott [3] and Obuchowski [2] we make use of all available data. Therefore, we follow the intent-to-treat principle as close as possible.
Current and Future Use of ICT for Patient Care and Management in German Acute Hospitals
Authors: Sellemann B. , Hübner U. 
Published: March 2018

Summary

Objectives:
This study aimed at gaining comprehensive information on the current status of patient care and management applications used in German acute hospitals. Since the degree of ICT coverage in hospitals depends on the attitude of the key decision makers we also wanted to capture their plans and priorities and herewith try to predict future use.

Methods:
We therefore conducted a nation-wide survey including all acute hospitals in Germany in which two questionnaires were mailed to each hospital, one to the nursing managers, the other to the hospital managers.

Results:
Six hundred hospitals participated in the survey which corresponds to an overall response rate of 27.6%. Accounting (84%) was found to be the most prevalent management module. Rostering was implemented in every second hospital. For clinical applications laboratory systems ranked first (69%). Ordering systems were used in nearly every second hospital. Nineteen percent of the hospitals reported employing an electronic patient record, 7% a nursing documentation system. Ranked by their priorities ordering systems hold the first position and care planning the last position. According to their plans, hospital managers, not nursing managers, intend to introduce nursing documentation. In contrast, nursing managers favor ordering and rostering for the near future.

Conclusions:
There is still a preponderance of management-oriented systems in German hospitals, yet clinical applications, in particular those supporting communications, will gain ground. The future of documentation systems is unclear, unless they not only provide statistical data for the management but support the clinical process properly.
A Simulation Study Using Validated Prognostic Factors to Assess Expected Long-term Survival
Authors: Hasford J. , Pfirrmann M. 
Published: March 2018

Summary

Objectives:
In chronic myeloid leukemia, after promising results in major cytogenetic remission (MCR), longterm survival data on imatinib treatment is of particular interest, especially in relation to former standard treatment based on interferon-alpha. However, data is still unavailable and due to high remission rates, most patients randomized to interferon-alpha in a clinical trial crossed over to imatinib. Therefore, to assess the expected long-term survival advantage with imatinib, a simulation study based on prognostic factors validated for interferon-alpha treatment was performed.

Methods:
In interferon-alpha-treated patients with intermediate-risk and low-risk according to the established New CML score, survival probabilities of patients with MCR were significantly higher than those of patients without MCR. Three samples with simulated survival data for imatinib-treated intermediate-risk patients were constituted by randomly drawing varying percentages of their survival times from interferon-alpha-treated intermediate-risk patients with MCR and the remaining data from intermediate-risk patients without MCR. The same procedure was applied to low-risk patients.

Results:
The 10-year survival probabilities of interferon-alpha-treated intermediate-risk and low-risk patients were 0.22 and 0.37. In the simulated samples, when 80%, 65%, and 50% of survival times were as favorable as for interferon-alpha-treated patients with MCR, respectively, the corresponding survival probabilities were 0.43 and 0.57, 0.36 and 0.49, and 0.30 and 0.42.

Conclusions:
In all simulation samples, increments of survival probabilities by imatinib were predicted, although survival probabilities of patients with MCR were assumed to be lower than with interferon-alpha. Prognosticated survival advantage with imatinib is backed by increasing observation time of imatinib-treated patients in real studies.
Genetic Epidemiology in Germany
Authors: Wichmann H.-E. 
Published: March 2018

Summary

Objectives:
Genetic epidemiology investigates the role of genetic factors and their interaction with environmental factors (in a broad meaning) for the occurrence of diseases in human populations. Its aim is to undest-and the influence of genetics on the development of dis-eases, their course and the clinical implications, with the final goal to improve prevention, diagnostics and therapy.

Methods:
Originally genetic epidemiology was understood as a specialized discipline with the main focus on family-based studies. The extraordinary development of genetics in the last decades – with respect of the understanding of the meaning of genes for human health, as well as by the availability of cost-effective high throughput methods in the lab, has opened enormous opportunities to study genetic factors. Now, genetic epidemiology and genetic statistics have a much broader application. In addition, access to large samples of patients or from the population is needed. This can be realized via biobanks.

Results:
Large biobanks with 500,000 or more patients or participants from the general population are being established or planned in the UK, Japan or the US. However, in Germany only two smaller activities are ongoing, KORA-gen in the south and POPGEN in the north. Possibilities to reach larger numbers, based on existing cohorts or disease networks are discussed. Ethical boundary conditions have to be taken into account, which seem to improve due to the Opinion of the German National Ethics Council on Biobanks for Research. Furthermore, the activities of the German centers for Genetic Epidemiological Methods (GEMs) as research and support units for genetic statistics and epidemiological methodology are described.

Conclusions:
Genetic epidemiology is based strongly on interdisciplinary collaboration and includes basics of genetics, elements of molecular biology to identify genes, population genetics, clinical medicine, and methodological disciplines as epidemiology, biostatistics and bioinformatics. In Germany the situation for this type of patient-based research has recently improved due to the National Genome Research Network (NGFN).
Knowledge for Medicine and Health Care
Authors: van Bemmel Jan H. 
Published: March 2018

SummaryDr. Donald A. B. Lindberg, Director of the U.S. National Library of Medicine, received an honorary doctorate from UMIT, the University for Health Sciences, Medical Informatics and Technology in Innsbruck, Tyrol. The celebration took place on September 28, 2004 at an academic event during a conference of the Austrian, German, and Swiss Societies of Medical Informatics, GMDS2004. Dr. Lindberg has been a pioneer in the field of computers in health care from the early 1960s onwards. In 1984 he became the Director of the National Library of Medicine in Bethesda, the world’s largest fully computerized biomedical library. Dr. Lind-berg has been involved in the early activities of the International Medical Informatics Association (IMIA), among others being the chair of the Organizing Committee for MEDINFO 86 in Washington D.C. He was elected the first president of the American Medical Informatics Association (AMIA), and served as an editor of Methods of Information in Medicine.
Atrial and Ventricular Myocardium Extraction Using Model-based Techniques
Authors: Fischer G. , Hanser F. , Seger M. , Hintermüller C. , Modre-Osprian R. , Trieb T. , Tilg B. , Pfeifer B. 
Published: March 2018

Summary

Objectives:
This paper presents an efficient approach for extracting myocardial structures from given atrial and ventricular blood masses to enable non-invasive estimation of electrical excitation in human atria and ventricles.

Methods:
Based on given segmented atrial and ventricular blood masses, the approach constructs the myocardial structure directly, in the case that the myocardium can be detected in the volume data, or by using mean model information, in the case that the myocardium cannot be seen in the volume data due to image modalities or artefacts. The approach employs mathematical and gray-value morphology operations. Regulated by the spatial visibility of the myocardial structure in the medical image data especially the atrial myocardium needs to be estimated repeatedly using the a-priori knowledge given by the anatomy.

Results:
The approach was tested using eight patient data sets. The reconstruction process yielded satisfying results with respect to an efficient generation of a volume conductor model which is essential when trying to implement the estimation of electrical excitation in clinical application.

Conclusion:
The approach yields ventricular and atrial models that qualify for cardiac source imaging in a clinical setting.
Introducing Patient Cards in Clinical Routine: Evaluation of Two Research Projects
Authors: Demski H. , Engelbrecht R. , Birkmann C. 
Published: March 2018

Summary

Objective:
Two research projects were analyzed in order to identify key factors of success and/or failure in introducing patient card-based systems in clinical routine.

Methods:
In DIABCARD an evaluation study focussing on user friendliness and user acceptance was conducted. In ByMedCard-HCPP the project’s system was validated and the timeliness of the project’s work analyzed.

Results:
User friendliness and user acceptance of the DIABCARD system were fairly high. The ByMedCard-HCPP system was complete in its major components and functionalities; introducing the ByMedCard-HCPP system in clinical routine delayed the project.

Conclusions:
A multitude of key factors of success such as utilized technologies, user involvement, and commitment of partners seems to contribute to the success and/or failure of introducing patient card-based systems in healthcare.
Standardized Documentation of Drug Recommendations in Discharge Letters
Authors: Pilz J. , Kaltschmidt J. , Ludt S. , Szecsenyi J. , Haefeli W. E. , Knaup P. 
Published: March 2018

Summary

Objectives:
To analyze the necessity and potential usefulness of a computerized physician order entry (CPOE) system in supporting the writing of pharmacotherapeutic recommendations in discharge letters.

Methods:
Systematic analysis of drug recommendations in discharge letters of a hospital providing tertiary care, structured interviews with in-hospital prescribers, and focus groups with general practitioners who admit patients to this hospital.

Results:
We analyzed 1800 randomly selected discharge letters, 1205 of which contained pharmaco-therapeutic recommendations. The frequencies, structure, and quality of these recommendations varied considerably between departments. Nearly 16% of the recommendations contained both proprietary (brand) and non-proprietary names (active ingredient). Interviewed clinicians expressed interest in CPOE systems that check for contraindications and interactions between drugs, suggest cheaper products, and automatically insert active ingredients when omitted. The focus group sessions confirmed that the pharmacotherapeutic recommendations in current discharge letters do not effectively support daily clinical practice.

Conclusions:
Documenting active ingredients as well as brand names in drug therapy recommendations is currently not part of clinical practice. Computerized decision support can help to optimise the structure and communication of therapeutic information across interfaces and can be a quality factor with considerable influence on process quality, outcome quality, and costs of cooperative patient care.
Evaluation of Health-related Internet Use in Germany
Authors: Dumitru R. C. , Prokosch H.-U. , Birkmann C. 
Published: March 2018

Summary

Objective:
An eHealth survey was conducted in a major Bavarian region in order to evaluate health-related Internet use in Germany.

Methods:
A specific questionnaire was developed by the authors to collect sociodemographic data as well as data on general and health-related Internet use. This questionnaire was distributed to patients visiting medical practices in the above mentioned Bavarian region.

Results:
Whereas many Internet users look for health-related information and products on the Internet, more advanced web-based techniques such as chat rooms and electronic patient records are hardly used.

Conclusions:
Although modern information technologies have the potential to enable citizens to handle their own health-related information in a self-determined and informed manner, at present the general population in Germany is hardly taking this opportunity.
The “Resident’s Dilemma”?
Authors: Gerber B. S. , Weiner S. J. , Heckerling P. S. 
Published: March 2018

Summary

Objectives:
Medical residents engage in formal and informal education interactions with fellow residents during the working day, and can choose whether to spend time and effort on such interactions. Time and effort spent on such interactions can bring learning and personal satisfaction to residents, but may also delay completion of clinical work.

Methods:
Using hypothetical cases, we assessed the values and strategies of internal medicine residents at one hospital for both cooperative and non-cooperative education interactions with fellow residents. We then used these data and cellular automata models of two-person games to simulate repeated interactions between residents, and to determine which strategies resulted in greatest accrued value. We conducted sensitivity analyses on several model parameters, to test the robustness of dominant strategies to model assumptions.

Results:
Twenty-nine of the 57 residents (50.9%) valued cooperation more than non-cooperation no matter what the other resident did during the current interaction. Similarly, thirty-six residents (63.2%) endorsed an unconditional always-cooperate strategy no matter what the other resident had done during their previous interaction. In simulations, an always-cooperate strategy accrued more value (776.42 value units) than an aggregate of strategies containing non-cooperation components (675.0 value units, p = 0.052). Only when the probability of strategy errors reached 50%, or when values were re-ordered to match those of a Prisoner's Dilemma, did non-cooperation-based strategies accrue the most value.

Conclusions:
Cooperation-based values and strategies were most frequent among our residents, and dominated in simulations of repeated education interactions between them.
Development of a Bayesian Network for the Prognosis of Head Injuries using Graphical Model Selection Techniques
Authors: Sakellaropoulos G. C. , Nikiforidis G. C. 
Published: March 2018

Abstract:The assessment of a head-injured patient’s prognosis is a task that involves the evaluation of diverse sources of information. In this study we propose an analytical approach, using a Bayesian Network (BN), of combining the available evidence. The BN’s structure and parameters are derived by learning techniques applied to a database (600 records) of seven clinical and laboratory findings. The BN produces quantitative estimations of the prognosis after 24 hours for head-injured patients in the outpatients department. Alternative models are compared and their performance is tested against the success rate of an expert neurosurgeon.