Objective. A limitation of studies comparing outcomes of Veterans Affairs (VA) and private sector hospitals is uncertainty about the methods of accounting for risk factors in VA populations. This study estimates whether use of VA services is a marker for increased risk by comparing outcomes of VA users and other patients undergoing coronary revascularization in private sector hospitals.
Data Sources. Males 67 years and older undergoing coronary artery bypass graft (CABG; n=687,936) surgery or percutaneous coronary intervention (PCI; n=664,124) during 1996–2002 were identified from Medicare administrative data. Patients using VA services during the 2 years preceding the Medicare admission were identified using VA administrative files.
Study Design. Thirty-, 90-, and 365-day mortality were compared in patients who did and did not use VA services, adjusting for demographic and clinical risk factors using generalized estimating equations and propensity score analysis.
Results. Adjusted mortality after CABG was higher (p<.001) in VA users compared with nonusers at 30, 90, and 365 days: odds ratio (OR)=1.07 (95 percent confidence interval [CI], 1.03–1.11), 1.07 (95 percent CI, 1.04–1.10), and 1.09 (95 percent CI, 1.06–1.12), respectively. For PCI, mortality at 30 and 90 days was similar (p>.05) for VA users and nonusers, but was higher at 365 days (OR=1.09; 95 percent CI, 1.06–1.12). The increased risk of death in VA users was limited to patients with service-connected disabilities or low incomes. Odds of death for VA users were slightly lower using samples matched by propensity scores.
Conclusions. A small difference in risk-adjusted outcomes for VA users and nonusers undergoing revascularization in private sector hospitals was found. This difference reflects unmeasured severity in VA users undergoing revascularization in private sector hospitals.