Monday, Nov 3
Melvin Stephens, Estimating Program Benefits
Vlahov, D., N. Galai, M. Safaeian, P. Duggal, Sandro Galea, G. Kirk, G. Lucas, and T.R. Sterling. 2005. "Effectiveness of Highly Active Antiretroviral Therapy Among Injection Drug Users with Late-Stage HIV Infection." American Journal of Epidemiology, 161: 1-14.
Highly active antiretroviral therapy (HAART) has been shown to be effective in different populations, but data among injection drug users are limited. Human immunodeficiency virus-infected injection drug users recruited into the Acquired Immunodeficiency Syndrome Link to Intravenous Experiences (ALIVE) Study as early as 1988 were tested semiannually to identify their first CD4-positive T-lymphocyte cell count below 200/mu l; they were followed for mortality through 2002. Visits were categorized into the pre-HAART (before mid-1996) and the HAART eras and further categorized by HAART use. Survival analysis with staggered entry was used to evaluate the effect of HAART on acquired immunodeficiency syndrome-related mortality, adjusting for other medications and demographic, clinical, and behavioral factors. Among 665 participants, 258 died during 2,402 person-years of follow-up. Compared with survival in the pre-HAART era, survival in the HAART era was shown by multivariate analysis to be improved for both those who did and did not receive HAART (relative hazards = 0.06 and 0.33, respectively; p < 0.001). Inferences were unchanged after restricting analyses to data starting with 1993 and considerations of lead-time bias and human immunodeficiency viral load. The annual CD4-positive T-lymphocyte cell decline was less in untreated HAART-era participants than in pre-HAART-era participants (-10/mu l vs. -37/mu l, respectively), suggesting that changing indications for treatment may have contributed to improved survival and that analyses restricted to the HAART era probably underestimate HAART effectiveness.