VIReC  Database and Methods Cyberseminar- 11 -Department of Veterans Affairs

**Department of Veterans Affairs**

**VIReC Database and Methods Seminar**

**Improving Mortality Ascertainment Using the VA Vital Status Dataset**

**Elizabeth Tarlov, PhD**

**August 6, 2012**

Margaret:  Welcome, everyone, to VIReC's database and methods cyber seminar entitled Improving Mortality Ascertainment Using the VHA Vital Status File.  Thank you to CIDER for providing technical and promotional support for this series.

Today's speaker is Elizabeth Tarlov, Ph.D., associate director of VIReC and research health scientist at the HSR&D Center of Excellence here at Hines VA Hospital.  Questions will be monitored during the talk in the Q&A portion of GoToWebinar and will be presented to Dr. Tarlov at the end of her talk.  A brief evaluation questionnaire will pop up when you close GoToWebinar.  We would appreciate if you would take a few moments to complete it.

I'm pleased to welcome today's speaker, Dr. Elizabeth Tarlov.

Dr. Tarlov:  Thank you, Margaret.  Hello, everyone.  Here's what you can expect to learn today, session objections.  At the conclusion of the program, participants will be able to identify data sources for Veteran vital status ascertainment, understand the contents and structure of the VA vital status file and their appropriate use for mortality ascertainment, and describe limitations of using the VHA vital status file to ascertain mortality.

And this is how we'll get there.  I'll start by providing some basic information about each source of mortality data that's available in the VA.  Then we'll drill down into the vital status files, their structure, contents, and the difference between the files.  To use the data properly, it's important to understand some of its quirks so we'll spend some time discussing challenges and strategies to address them.  And finally, I'll provide some information about additional resources that you may find useful.

But first we'd like to take a short audience poll.  In a moment you'll see the poll, and we'd appreciate your telling us how would you rate your knowledge of methods to ascertain death dates for Veterans in the VA.  And you should see the poll now, and your answer's on a scale from one to five where one is no knowledge and five is expert.

(Pause)

Dr. Tarlov:  And Heidi, are you there?  Hello?

Heidi:  Yes, right now – yep, I'm here.  Can you hear me?

Dr. Tarlov:  Yes, I can hear you.

Heidi:  We are at about – okay, we're at about 80 percent right now so I'm going to close it out and show the results.  There you go.

Dr. Tarlov:  Okay, so about a third have no knowledge, 33 percent rated themselves as a little bit of knowledge, and another 24 percent kind of in the middle there.  Okay, thank you very much.

The second question is have you ever used the VHA vital status file.  One is yes if you've used the master file, two if you've used only the mini file, and three neither.

(Pause)

Heidi:  And we're at about 75 percent right now.  I'll give it just a couple more seconds and close it out.

(Pause)

Heidi:  And there you go.

Dr. Tarlov:  Okay, 73 percent not at all, 11 percent have used the vital status mini file only, and another 16 percent have used the master file.

Okay, thank you very much for that information, and we'll go ahead and proceed.  Okay, our first topic – I'm trying to get rid of my thing here – okay.  Our first topic, data sources for Veteran vital status ascertainment.  The BIRLS death file, the Beneficiary Identification and Records Locator System, is a VBA database.  The BIRLS death file is an extract from that database.  VBA obtains death dates from a variety of sources including families, VA hospitals and the National Cemetery Administration, as well as the Social Security Administration.

Its coverage is any Veteran that VBA knows about which will include any who's applied for or received benefits from any of the three administrations so that includes, but isn't limited to, all Veterans who've used VA healthcare.

VHA receives a new updated BIRLS death file each month.  This is a change from the previous practice which was to simply receive and incorporate into the file new death dates.  So now there's a monthly complete overlay of the file, and this file resides on the AITC mainframe computer.

The VA CMS vital status file is received annually from CMS.  CMS obtains dates of death from multiple sources but chiefly the Social Security Administration.  Death dates included in this file will be those for Veterans enrolled in Medicare which means principally those who are disabled, are 65 years or older, or have end stage renal disease.  Most Veteran deaths under age 65 will not be captured in this file.

This file is updated annually.  The file we currently have in the VA was created by CMS in December 2011, and this file is available to researchers from VIReC and for operations use through the Medicare Analysis Center.

VA also obtains Social Security Administration death master file data.  SSA obtains death date information from multiple sources that include the National Center for Health Statistics which creates the National Death Index containing death certificate data from state vital statistics offices.  The SSA death master file coverage is anyone who's obtained a Social Security card since 1936.  This does include deaths occurring outside the U.S.  However, the death data has been found to be more complete among the over 65 population.  And that three should be a superscript.  There's a reference list at the end of this presentation.

The VA data from SSA are updated weekly.  Annually a complete overlay file is received, and this file also resides on the AITC mainframe.

The three files I've just discussed are all from outside VHA.  VA workload data also contains death dates when the death has occurred in the inpatient setting.  The patient treatment file contains inpatient data from patients in VA hospitals and also for patients in non-VA hospitals when the stay is covered by VA, known as fee basis care.  PTF data may be better known to many of you as the inpatient data contained in the National Patient Care database and medical SAS datasets.  I'm referring to it here as PTF because that's how it's labeled in the vital status file, and I want to be consistent with the terms I'm using here.

Workload data are extracted from Vista to the patient treatment file so new death dates may appear in this file monthly.  I should note here as well that the same dates extracted from Vista also go to the corporate data warehouse inpatient domain.

Finally, I want to mention a new source of death data in the VA.  The Serious Mental Illness Treatment Resource and Evaluation Center, SMITREC, has recently acquired death data from the National Death Index, the NDI, I mentioned earlier when discussing the SSA death master file.  The NDI, because it includes all death certificate data from every state vital statistics office, is considered the gold standard in terms of completeness.  It also is the only national source of cause of death information in the U.S.

The data that the SMITREC has obtained will include death information for any Veteran who has used VHA inpatient or outpatient services between 1998 fiscal year and fiscal year 2009 and has no indication of being alive based on VHA utilization.  In addition, this data will include deaths for Veterans in the OEF/OIF roster regardless of whether they've used VHA.  The data are currently complete through – in other words, covering deaths through the end of fiscal year 2009, and this is the only source of cause of death data in VA.

It says there's contact information below.  Actually, that's not the case and I invite you to contact the VIReC help desk for that contact information.

Completeness of mortality ascertainment, the last thing I want to show you before moving onto the vital status files is this information about the completeness of the death data in each of the sources I've discussed that contribute information to the vital status files.  So that doesn't include the bottom row, the SMITREC NDI data.  I'm thinking of completeness here as both sensitivity using NDI as the gold standard and the degree to which the data reflect recent deaths.  The sensitivity information is based on results of two studies listed at the end of the presentation, one of which is VIReC's VA NDI mortality data merge project.  Sensitivity varies by age so the numbers tend to be ranges, and the right column shows the most recent death dates found for each source in the vital status file built last month.  BIRLS has been found to capture it most, 80 percent of deaths occurring among Veterans as you can see there, but it includes very recent deaths.

Okay, the VHA vital status files.  First, a little background.  The impetus for creating the VHA vital status file was that death is an important measure in research, and analyses have shown that the individual datasets could provide conflicting information about whether individuals were dead or not and were, as single files, incomplete.  VIReC undertook the VA NDI mortality data merge project in 2003 to investigate this more systematically by comparing information in each file and the files together to the gold standard, the National Death Index.  A recommendation that came out of this study was the creation of a new file of combined mortality data.

So in 2006 National Data Systems built the first VHA vital status files.  The files are updated quarterly, and they include information on all Veterans known to the VA who were alive on October 1, 1991 or who were born since then.  The vital status file actually comprises two files that I'll discuss in some detail, and there's a third file which is a scrambled SSN-to-SSN crosswalk.

I'm going to talk first about the vital status master file.  This file includes records for both Veterans and non-Veterans who've received VA services.  For each SSN there's one record for each unique combination of SSN, date of birth, and sex found in the combined data.  The numbers you see here are from a version of the file from 2011.  There were over 22 million records on the vital status master file, 15.8 million unique SSNs.  Sixty-five percent of the SSNs have only one record and 35 percent have multiple records, and there are over 1.7 million non-Veteran SSNs on the file as well.  The vital status master file contains 112 variables.

In contrast, the mini file has just one record per SSN.  A single record contains combined data for that SSN.  The mini file has over 14 million records and just 16 variables.

I'm going to be talking in some detail about the construction of the vital status master file, and so I want to spend just a moment kind of giving a little bit of background to explain why I'm going to go into that detail.  In planning to use the vital status file to ascertain deaths in a research cohort or sample, there are several decisions to be made.  Will we use the mini file, the master?  How will we identify the records for the individuals in our cohort?  Will we do that using the Social Security Number only, by some combination of SSN, date of birth, and gender?  And if it's the latter, how conservative will the match criteria be?  So what, if any, partial matches will be accepted?

Some of the issues that can come up in this regard are mismatched demographics and activity after a date of death.  In terms of mismatched demographics, your cohort member's Social Security Number matches a record on the vital status file but the demographics are different.  The date of birth or the sex or both in your records don't match those on the vital status file record.  In terms of activity after death, this refers to the fact that the vital status file contains dates of last activity from each data source.  For example, last healthcare utilization or last date of a VBA transaction.  In a recent VIReC analysis, nearly five percent of all deaths had a last activity date that was more than 31 days after the death date.  So it's important to understand the construction of the files because that will help you to address these issues.

The first step in building the vital status file is to combine data from VBA and VHA sources.  The merge is done on the SSN, date of birth, and sex so there will be one record per combination of SSN, date of birth, and sex.  The data include last activity date from each source.  Also in this data will be inpatient deaths from the PTF.

These are the VA data sources.  Each has a SSN/date of birth/sex combination, and I'll note that a missing date of birth or sex is treated as a value in this merge.  In addition to PTF data, data are from the outpatient and inpatient encounters files, fee basis files, DSS pharmacy files, enrollment data, and VBA compensation and pension files.  Note the acronyms for each as the naming conventions for variables from each source include the acronym as you'll see in later slides.

The next step in building the file is to add the death data from sources external to VHA.  In this step, the linkage uses the SSN only.  This data contains date of birth and sex as well as date of death.  The external sources of death data are Medicare, Social Security Administration, and BIRLS.  The SSA file, though, does not have sex information.  Note that because the merge is done on the SSN only, the same death dates and other information, the demographics, will be added to every record for that SSN.

The next step in constructing the vital status file is the selection of a best date of death for each SSN/date of birth/sex combination.  NDS uses an algorithm that selects from among multiple values associated with an SSN when there's more than one record in the file for that SSN.  The goal, of course, is to select the true value for the variable in the majority of cases.  The algorithm starts by selecting the inpatient death date, if present, and the algorithm is detailed in Appendix A of this slide set.

So at the conclusion of that procedure, each record on the master file has a variable called DOD which is the selected best date of death, and the building of the master file is complete at that point.

So to kind of put this all together, the master file has one record for each VA SSN/date of birth/sex combination.  There is one set of date of birth and sex variables for each source of data, VA or not, on the vital status file data and that set could include a missing value for sex or date of birth or an incomplete date.  The variables containing date of birth and sex from each VA source will contain the same values on every record for that SSN.  The death dates from Medicare, BIRLS, and SSA are the death dates for the SSN on that record.  The date of birth and sex from those sources may not match the date of birth and sex values on the record.

The master file includes variables containing the dates of last activity from each VA source and from Medicare.  For those familiar with Medicare data, the Medicare last activity dates exclude information from DME and from unpaid carrier claims.  The master file also contains variables from the sources shown here: outpatient, inpatient, enrollment, and comp and pen, indicating whether that source has identified the individual as a Veteran.

The Medicare Analysis Center or MAC prepares the Medicare data for the vital status file.  Also included from the Medicare data is race information and also submission flags indicating for each year whether the SSN was included in the finder file that was sent to CMS and, if so, whether CMS records indicated the individual was enrolled in Medicare that year.  The master file also contains variables indicating the quality of each date.

I'll move now to the mini file.  The mini file is constructed from master file data.  It's a distilled version of that file that combines data to create a single record for each SSN.  To do that, algorithms are run to select a best date of birth, in quotes, best date of birth and sex as well as the best date of death.  And the mini file includes additional variables to assistant in determining vital status which I'll discuss in a bit.

The mini file contains Veteran records only.  For the approximately 65 percent of SSNs for which there is one record only on the master file, there's no question about which date of birth and sex values get included in the mini.  The best date of death previously selected through the algorithm is also included in the mini file.  And for SSNs with multiple records on the master file, remember this means there are multiple date of birth and sex combinations, an algorithm is run to select a best date of birth and sex.  Those values and the best date of death are selected for inclusion in the master file.

I've already discussed this so I'm going to move on.

The algorithm used to select the best date of birth is complex, and it is detailed in Appendix B at the end of the slide set.  In brief, utilization dates are preferenced and a scoring method is used that gives a higher score for dates that are complete, if sex is not missing, and if they both match external sources.  If sex values for an SSN are conflicting, a quote/unquote best sex is selected using a similar process, and we've already discussed the best date of death.

The final selection of data from the master file to go into the mini is last activity.  Two dates are selected, one from utilization data and the other from all last activity including utilization.  That's healthcare utilization I'm referring to.  When there are multiple records for an SSN, these dates reflect last activity from all records combined.

Also, a presumed living status is assigned to each SSN.  It can take on one of three values as shown here indicating presence of a death date and whether or not the last healthcare utilization date is more than 31 days after death.  The last activity dates on the VHA vital status file often may be used to reduce the number of patients lost to follow up.

To put this all together for the mini file, there's one record per SSN on the mini file.  On that one record are three demographic variables: the best dates of birth and death and best sex.  There are two dates of last activity, one for healthcare utilization and the other overall.  The presumed living status variable is included.  And finally, there are variables to indicate the data source for each date.

This table shows the distribution of sources for dates of birth on the mini file.  A version of the file from 2011 was used for this analysis, and as you can see, over half of the dates of birth that were selected for inclusion in the mini file come from encounter data.  Another quarter come from PTF data, and most of the rest are either Medicare, vital status, or enrollment file.

VIReC looked at the consistency of birth dates on the master file, and this table shows the results of that analysis which used the file created in June 2010.  There were nearly 20 million records on the master file at that time.  Fourteen million of those were Veteran SSNs.  1.4 percent of those SSNs had conflicting information on date of birth.  Thirty-six percent – excuse me, I'm sorry, I knew I was – 1.4 percent of those had, it says on the slide, conflicting information on gender.  Thirty-six percent had conflicting information on date of birth.  But remember that a missing date or a missing part of a date is treated as a unique value.  If we ignore the missing values and look for conflicting date information, we find that 7.3 percent of the Veteran SSNs on the file had conflicting date of birth information.

This slide shows the data source for the dates of death on the mini file.  There were 4.4 million dates of death on the file.  Fifty-six percent came from the Medicare vital status file, 24 percent from the Social Security Administration death master file, 15 percent from PTF, and the remaining from BIRLS and fee basis.

I'll move now to discussing in some more detail some of the challenges that we run into in using the vital status file to ascertain mortality.  Potential challenges in using the files to ascertain deaths in research include demographics that don't match the demographics you have for an SSN in your study data and activity after the date of death.  I'm going to provide three examples to illustrate the issues that arise related to these things.  The first I'll refer to as scrambled SSN 11111.  For this SSN the date of birth on the vital status master file does not match your study patient's date of birth.  Second, scrambled SSN 22222 has a last activity date that's more than two years after the death date.  And the third is kind of a whopper.  The vital status file date of birth and sex do not match your patient date of birth and sex and the last activity date is after the death date.

This table shows selected data from master file records for scrambled SSN 11111.  There are two records for this SSN, and they have different dates of birth, both of them from VHA encounter data.

This is the same SSN and it has one death date, and CMS vital status file is the source of that date.  Because CMS data is linked to VA data using the SSN only, the CMS date of death will be added to both records regardless of the date of birth that's on the CMS file.  The mini file record built for this SSN is shown in the bottom portion of the slide.  Because there were conflicting dates of birth for this SSN, a best date of birth was selected.  The date of death is September 10, 2006, and the last utilization date selected was September 5, 2006.  And finally, the presumed living status indicator has a value of one indicating deceased.

This is SSN 22222, a male born July 15, 1944.  This SSN has two records on the master file, but in this example, the date of birth and the sex on the two records are conflicting.  The conflicting information was from VA encounter data, and note on the first record there is also a PTF date of birth.  So PTF data has the same date of birth and sex as the first encounter date of birth and sex shown here, both of them July 15, 1943.  There was a CMS date of death for this scrambled SSN, and it appears on both records.

On the mini file record for 22222 a best date of birth was selected from among the two records.  The date of death is the one date of death available for this SSN, September 10, 2006.  But note there was activity for this SSN as recently as June 12, 2009.  Therefore, the presumed living indicator is assigned a value of two to indicate the presence of a death date but a record of utilization more than 31 days after that death date.

This is the vital status master file record for SSN 33333.  There's only one record for this SSN indicating that all VA data sources agree on the date of birth and sex.  However, there are two sources of death data, SSA and CMS, and those dates conflict.  Also note there that the SSA and CMS date of birth are identical, May 31, 1968, but they don't match the VA date of birth on this record which is August 30, 1980.  Also, the CMS sex is male while the VA sex is female, and there's no SSA date of birth there because SSA data don't include sex.

Looking at the mini file record, because there were two different dates of death on the master file, a best date of death was selected.  The SSA date of death was selected, November 18, 2005.  Important to note here is that the date of birth for this SSN on the SSA file – look again at the master file record above – does not match the VA date of birth.  The SSA date of birth does not match the VA date of birth.  And the last utilization date for this SSN was May 9, 2009.  So the presumed living indicator is assigned a value of two.

These examples point out the following.  You may find inconsistencies between VHA vital status file demographics and your cohort demographics.  To resolve these inconsistencies, the master file will be useful.  And a note regarding non-research work: the VHA vital status file should not be used for business operations regarding individual Veterans' dates of death and vital status ascertainment.

So given all this, which file should researchers use?  The mini file is far simpler to use than the master, but there's a certain amount of guesswork involved in the demographics, including the death dates on the file.  There's no one right way to use these files.  One strategy is to use the mini file initially to search for deaths matching on the SSN only.  A second step would be to check the agreement between your patient date of birth and sex and the mini file record date of birth and sex.  If they don't match, it may be worth checking the master file since there may be a master file record for that SSN that has a date of birth and sex that match the patient date of birth and sex on your files.  It's possible that that record has a different date of death.

Another scenario where checking the master file would be a good idea is in cases where the mini file record indicates activity after death.  Look at the date of birth and sex for sources that provide a death date.  So this would be in the master file where there could be more than one death date.  If there's another date of death for this SSN on the file, there's a possibility that there is no activity after that death date.  Then I'd recommend checking the date of birth and sex from that date of death source to see whether it matches yours.

Additional steps you may want to consider to ensure that your death ascertainment is as complete and accurate as possible.  Compare the date of birth and sex for the date of death source on the master file to cohort date of birth and sex for all deaths.  Use the NDI or state vital statistics offices for cases lost to follow up.  The scenarios you see there on the slide, there's no death date, no VHA or VBA activity after the end of follow up, and if you were to request NDI data, you want to remember that the NDI has an 18-month lag in its death dates.

A couple of future enhancements, things to look forward to that may add to the vital status file or improve the – add to the information that we have about the vital status file.  VIReC has a report in production that quantifies missing and conflicting demographics on the file that will be published on our website soon, and it also evaluates the best date of birth algorithm.  In future, Medicaid data may provide additional death data which would be particularly helpful for ascertaining death among Veterans under 65 years old.  Also, not noted on the slide is that VA now also receives death data from the National Cemetery Administration.  This is a very recent development and this data has not yet been incorporated into the vital status file, but the intention is to do that over the next month.

Finally, where to go for more help.  Some helpful resources, Dorothea Garrett and Larry Hughes from National Data Systems are very knowledgeable about the vital status file and they're willing to help.  You can obtain their contact information if you don't have it by contacting the VIReC help desk.  VIReC's new websites have a lot of information about the vital status files and the source data.  And don't forget the HSRData Listserv.  This is a discussion forum for VA data users.  You must be behind the VA firewall to participate.  You can post questions and get responses from people with a lot of experience, and past messages are archived and searchable.  If you are not subscribed, go to the VIReC website for instructions on how to do that.  And VIReC has a help desk.  We're happy to answer questions when we can or direct you to where you can get an answer.

And that completes my presentation.  I think we have some time for questions.

Margaret:  Thank you very much.  First question, does the mini file contain a best date last seen that can be used for Kaplan-Meier survival analyses?

Dr. Tarlov:  Margaret, I'm going to ask you to repeat that, and also the volume, I'm having a little trouble hearing you.  Let me try increasing my volume.

Margaret:  Okay.  Can you hear me now?

Dr. Tarlov:  Yeah, I think that's a little better.  I'm sorry, could you repeat the question?

Margaret:  Sure.  Does the mini file contain a best date last seen that can be used for Kaplan-Meier survival analyses?

Dr. Tarlov:  The mini file will contain two last utilization dates, but one of them is the last healthcare utilization from VA workload data and the other is a last activity date from all of the files, including the VA enrollment file, the CMS and VBA data.  Those fields will contain the most recent date.  There is no attempt to determine the greater reliability of one over another.

Margaret:  Okay.  Could you summarize data source for last activity and last utilization dates on the mini file?

Dr. Tarlov:  Sure.  Let's see if I can go back – take us back to that section.  On the mini file.  Okay, well, that will be, as I just said, simply the most recent dates that are on the master file.  So let's go back to there and hopefully you can see that.  No, that didn't work at all.  I'm sorry.  Okay.  Last activity dates are from all of the VA sources.  So that will include the PTF, the outpatient and inpatient encounters data.  It will include the DSS pharmacy data and enrollment activity, as well as a VBA transaction date.  I don't know if that answers the question.  And then the most recent of those dates are included on the mini file.

Margaret:  Could you summarize the various possible values for the living indicator in the mini file?

Dr. Tarlov:  Sure.  Let's go back to there.  Here we go.  Zero indicates that there was no death date in any of the data for that SSN, and therefore, a zero would indicate that one would presume that person is living.  A one indicates that there's a death date and also that there was no healthcare usage that was more than 31 days after death.  A two on the other hand would indicate there's a death date but there's a record of utilization more than a month after death.  So a two then lends some question to the death date as to whether that person is actually dead.  Now, the issue of activity after death is a complicated one.  There are several reasons why that can be legitimate as opposed to, say, data error or you've got the wrong SSN.  And there was a recent – there have been several conversations on HSRData by the way that focus on activity after death, and so that's a good place to go for that.  But a two for the presumed living indicator would suggest that there's a possibility that there may be a question about the death date.  And that could be a reason why you might want to go to the master file to look at that a little bit more closely.

Margaret:  Okay.  Can you repeat where the presentation can be accessed in the future, your presentation which would be on the HSR&D cyber seminar archives.

Dr. Tarlov:  Is that the answer, Margaret?

Margaret:  Yeah, I would say that's the best place to look for it maybe in 24 hours.  Okay, next question.  Since spouses tend to use a husband's SSN, if spouse was being seen in DOD, I guess Department of Defense, is there any effort to capture DOD date of death?  Want me to read that again?

Dr. Tarlov:  Yeah, please.

Margaret:  Since spouses tend to use a husband's SSN, if spouse was being seen in DOD, is there any effort to capture DOD DOD?  Which would be, I guess, Department of Defense date of death.

Dr. Tarlov:  There is no Department of Defense data, per se, in the vital status file.  Now, I wonder whether the questioner meant to ask about the VBA data, and there are, in fact, beneficiaries in the VBA compensation and pension files.  However, those records are indicated so we're able to tell which of those records are for beneficiaries rather than for a Veteran.  So there should be no beneficiary data on the vital status file.

Margaret:  Okay.  Can a non-VA researcher access this data source?

Dr. Tarlov:  A non-VA researcher has a couple of options.  One is to collaborate.  Your best option is to collaborate with a VA researcher or, of course, be employed by the VA.  And if you want to contact the VIReC help desk, we'd be happy to talk to you a little bit more about that.  But the answer is not without some status as a collaborator or having some appointment in the VA.

Margaret:  Okay.  There are no more questions at the moment.  In case somebody's typing madly, let me just announce our next session.  We will not have a session in September because of Labor Day.  The next session will be Monday, October 1, same time, and the seminar is Overview of VA Data Information Systems, National Databases, and Research Uses.

And I believe we are finished.  Thank you, Dr. Tarlov.  Thank you, audience.

Dr. Tarlov:  You're very welcome.

Margaret:  Okay, bye.

Dr. Tarlov:  Bye bye.

**[End of Recording]**

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