ObjectiveRecent advances in antiretroviral therapy have led to effective but increasingly complex strategies for the treatment of HIV infection. In a previous study, we demonstrated that physicians' experience in the care of patients with AIDS improves survival. We conducted this study to determine whether greater physician experience is associated with earlier adoption and appropriate use of new antiretroviral treatment regimens.DesignRetrospective medical record review of a population-based sample of HIV-infected individuals who received antiretroviral treatment between December 1995 and May 1997 by primary care physicians practicing throughout the state of Washington. We classified antiretroviral regimens observed into one of four categories based on national treatment guidelines.ResultsThe use of new antiretroviral treatment regimens significantly increased during the study period; 22% of patients were treated with a protease inhibitor (PI)-based regimen or an alternative PI-or nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen between December 1995 and November 1996, compared with 57% between April and May 1997 (p< .001). After controlling for CD4 count and the calendar period of treatment, patients cared for by physicians with greater HIV experience were significantly more likely to receive PI-based regimens or alternative PI-or NNRTI-based antiretroviral regimens (p= .02). Use of PI-based regimens was also associated with lower CD4 count (p< .001) and treatment after January 1997 (p= .02), but independent of patient demographic characteristics and the geographic location of physicians' practices.ConclusionsGreater physician experience in the care of persons with HIV infection is associated with earlier adoption of new antiretroviral treatment regardless of whether physicians practice in a rural or urban area.