Using the national registry of HIV-infected veterans in research

Disease-specific registries have many important applications in epidemiologic, clinical and health services research. Since 1989 the Department of Veterans Affairs has maintained a national HIV registry. VA's HIV registry is national in scope, it contains longitudinal data and detailed resource utilization and clinical information. To describe the structure, function, and limitations of VA's national HIV registry, and to test its accuracy and completeness. The VA's national HIV registry contains data that are electronically extracted from VA's computerized comprehensive clinical and administrative databases, called Veterans Integrated Health Systems Technology and Architecture (VISTA). We examined the number of AIDS patients and the number of new patients identified to the registry, by year, through December 1996. We verified data elements against information obtained from the medical records at five VA sites. By December 1996, 40,000 HIV-infected patients had been identified to the registry. We encountered missing data and problems with data classification. Missing data occurred for some elements related to the computer programming that creates the registry (e.g., pharmacy files), and for other elements because manual entry is required (e.g., ethnicity). Lack of a standardized data classification system was a problem, especially for the pharmacy and laboratory files. In using VA's national HIV registry we have learned important lessons, which, if taken into account in the future, could lead to the creation of model disease-specific registries.