Brief Report: Comparison of Methods to Identify Iraq and Afghanistan War Veterans Using Department of Veterans Affairs Administrative Data

Article excerpt

INTRODUCTION

More than 2 million servicemembers have served in Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) and nearly 1.2 million have been discharged as veterans. Veterans from these conflicts have experienced multiple deployments and unique combat environments [1-3], along with high rates of psychiatric disturbance and physical injury [4-7]. Recognizing the importance of the healthcare needs and demands of OIF/ OEF veterans, the Veterans Health Administration (VHA) has solicited research focused on them [8-9].

The Department of Veterans Affairs (VA) health services use SAS data sets found in the Austin Information Technology Center (AITC) contain national VHA-provided healthcare information on veterans, which researchers use to identify patient populations [10-11]. Using these data sets, VA researchers can identify periods of service (POS) for veterans who have served from the Spanish-American War to the gulf war. However, VA researchers cannot search the VA health services use SAS data sets by POS to identify OIF/OEF veterans because Congress has not designated OIF/OEF as a POS. Other methods are therefore needed to identify this priority group.

The VHA Support Service Center OIF/OEF Roster is arguably the gold standard for identification of OIF/OEF veterans [12-14]. The OIF/OEF Roster is cataloged by the Department of Defense's Defense Manpower Data Center (DMDC) and has been provided to VHA's Environmental Epidemiology Service (EES) since September 2003. This comprehensive database includes identifying information on VA-registered OIF/OEF veterans with military discharges starting October 1, 2001, who were (1) physically located within the OIF/OEF combat zones or areas of operation or (2) identified by their service branch as directly supporting the OIF/OEF mission outside designated combat zones. ** This data set is not available to researchers without funded studies. Furthermore, the approval process, although appropriate given the need to ensure veteran privacy and data security, can take several months. Another method for identifying OIF/OEF veterans is self-reported POS on surveys or during interviews. This method, however, cannot be used for selection of OIF/OEF veterans before data collection.

In this article, we describe results from two studies that compare an algorithm we developed to identify OIF/ OEF VA users that makes use of variables available in the Outpatient Visit (SF) file of the VA health services use database. We compared this OIF/OEF Algorithm with the OIF/OEF Roster (study 1) and then with veterans' self-report surveys (study 2). We describe the positive predictive value (PPV) and sensitivity of our OIF/ OEF Algorithm and also present differences between veterans we identified using our OIF/OEF Algorithm against those we failed to identify according to the OIF/ OEF Roster and self-report survey. Findings will help investigators determine the most appropriate approach for identifying OIF/OEF veterans for their research.

METHODS

Samples and Study Design

Study 1 included two samples: (1) a national sample of OIF/OEF veterans who used VA healthcare from fiscal year (FY) 2004 to FY2007 selected on the basis of the OIF/OEF Algorithm (outlined in the Figure) for a study examining OIF/OEF veteran reintegration problems and treatment interests and (2) OIF/OEF veterans included in the OIF/ OEF Roster with military discharges through December 2007 who had VA health services use data from FY2004 to FY2007. Study 2 included a sample of veterans who had at least one diagnosis of posttraumatic stress disorder (PTSD) in VA health services use data during FY2008 or FY2009 for a study of PTSD treatment participation. In study 2, we compared those who self-reported OIF/OEF POS on the completed survey with those we identified as OIF/OEF veterans using the OIF/OEF Algorithm.

Measures

For study 1, we used VA health services use data to obtain demographic information and health services use information, including psychiatric diagnoses and use of a VA facility in the past 2 years. …