Physician specialization and antiretroviral therapy for HIV: Adoption and use in a national probability sample of persons infected with HIV

BACKGROUND: Since the introduction of the first protease inhibitor in January 1996, there has been a dramatic change in the treatment of persons infected with HIV. The changing nature of HIV care has important implications for the types of physicians that can best care for patients with HIV infection. OBJECTIVE. To assess the association of specialty training and experience in the care of HIV disease with the adoption and use of highly active antiretroviral (ARV) therapy (HAART). DESIGN: Observational cohort study of patients under care for HIV infection and their physicians. PATIENTS AND SETTING: This analysis used data collected from a national probability sample of noninstitutionalized persons with HIV infection participating in the HIV Costs and Service Utilization Study and their primary physicians. We analyzed 1,820 patients being cared for by 374 physicians. MEASUREMENTS: Rates of HAART use at 12 months and 18 months after the approval of the first protease inhibitor. RESULTS: Forty percent of the physicians were formally trained in infectious diseases (ID), 38% were general medicine physicians with self-reported expertise in the care of HIV, and 22% were general medicine physicians without self-reported expertise in the care of HIV. The majority of physicians (69%) reported a current HIV caseload of 50 patients or more. In multivariable models controlling for patient characteristics, there were no differences between generalist experts and ID physicians in rates of HAART use in December 1996. When compared to ID physicians, however, patients being treated by non-expert general medicine physicians were less likely to be on HAART (odds ratio [OR], 0.32; 95% confidence interval [95% CI], 0.17 to 0.61). Patients being treated by low-volume physicians were also much less likely to be on HAART therapy than those treated by high-volume physicians (OR, 0.26; 95% CI, 0.14 to 0.48). These findings were attenuated by June 1997, suggesting that over time, the broader physician community successfully adopted HAART therapy. This finding is consistent with prior research on the diffusion of innovations. CONCLUSIONS: Similar proportions of patients treated by expert generalists and ID specialists were on appropriate HAART therapy by December 1996 and July 1997. Patients treated by non-expert generalists, most of whom were the lowest-volume physicians, were much less likely to be on appropriate ARV therapy in the earlier time period. Our findings demonstrate that generalists who develop specialized expertise are able to provide care of quality comparable to that of specialists.