AEGiS-14IAC: Does HAART fully explain the improved survival of injection drug users in recent years?

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Does HAART fully explain the improved survival of injection drug users in recent years?

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. ThOrC1445)

Vlahov D, Galai N, Bareta JC, Cohn S, Galea S, Sterling T, Margolick JB
New York Academy of Medicine, New York, United States

BACKGROUND: Since the introduction of highly active antiretroviral therapy (HAART), survival of HIV infected persons has increased substantially. At the same time, more aggressive treatment and prophylaxis of opportunistic infections (OI) also occurred. We evaluated the survival difference attributable to HAART among injection drug users (IDUs), adjusting for CD4 cell count and other known prognostic factors.

METHODS:601 HIV+ IDUs were followed from 1988-2000 with semi-annual interviews and laboratory tests. Time to HIV-related death was estimated from the first visit at which CD4 cell count was <200 cells/ul. Kaplan-Meier survival curves pre-HAART (1988-96) and post-HAART (1996-2000) were compared, accounting for actual HAART use. Time-dependent Cox regression models were used to model time to death, adjusting for these and other prognostic factors.

RESULTS: Survival estimates for the pre-HAART period, post-HAART with no individual HAART treatment, and post-HAART with actual treatment were respectively: 0.94, 0.93, 1.0 at one year and 0.57, 0.85, 0.96 at 3 years. A significant residual survival benefit in the post- HAART period remained (adjusted hazard ratio (HR) 0.52, p=0.002) after adjustment for individual use of HAART (HR=0.32, p=0.007), PCP-prophylaxis (HR=0.68, p=0.02), AIDS diagnosis(HR=10.3, p<0.001), CD4 cell counts (HR=0.99,p<0.001) and hemoglobin levels (HR=0.78, p<0.001). Reported treatment for OIs other than PCP, frequent injection, age and gender and viral load) did not have a significant effect on survival.

CONCLUSIONS: For IDUs with low CD4 cell counts, the rate of HIV-related death decreased significantly in the post-HAART era. However, improved survival was only partially explained by reported HAART and PCP prophylaxis. The additional unexplained benefit could reflect the selective mortality of 'heavy' drug users of non HIV-related causes and the parallel observed reduction in drug injection frequency, but warrants further study.

Keywords: AEGIS, Antiretroviral Therapy, Highly Active, CD4 Lymphocyte Count, HIV Infections, Viral Load, Proportional Hazards Models, Survival Analysis, Survival, mortality

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