Long-term effectiveness of potent antiretroviral therapy in preventing AIDS and death: a prospective cohort study
The Lancet, 2005•thelancet.com
Background Evidence on the effectiveness of highly active antiretroviral therapy (HAART) for
HIV-infected individuals is limited. Most clinical trials examined surrogate endpoints over
short periods of follow-up and there has been no placebo-controlled randomised trial of
HAART. Estimation of treatment effects in observational studies is problematic, because of
confounding by indication. We aimed to use novel methodology to overcome this problem in
the Swiss HIV Cohort Study. Methods Patients were included if they had been examined …
HIV-infected individuals is limited. Most clinical trials examined surrogate endpoints over
short periods of follow-up and there has been no placebo-controlled randomised trial of
HAART. Estimation of treatment effects in observational studies is problematic, because of
confounding by indication. We aimed to use novel methodology to overcome this problem in
the Swiss HIV Cohort Study. Methods Patients were included if they had been examined …
Background
Evidence on the effectiveness of highly active antiretroviral therapy (HAART) for HIV-infected individuals is limited. Most clinical trials examined surrogate endpoints over short periods of follow-up and there has been no placebo-controlled randomised trial of HAART. Estimation of treatment effects in observational studies is problematic, because of confounding by indication. We aimed to use novel methodology to overcome this problem in the Swiss HIV Cohort Study.
Methods
Patients were included if they had been examined after January 1996, when HAART became available in Switzerland, were not on HAART, and were free of AIDS at baseline. Cox regression models were weighted to create a statistical population in which the probability of being treated at each time point was unrelated to prognostic factors.
Results
Low CD4 counts and increasing HIV-1 viral load were associated with increased probability of starting HAART. Overall hazard ratios were 0·14 (95% CI 0·07–0·29) for HAART compared with no treatment, and 0·49 (0·31–0·79) compared with dual therapy. Compared with no treatment, HAART became more beneficial with increasing time since initiation but was less beneficial for patients whose presumed mode of transmission was via intravenous drug use (hazard ratio 0·27, 0·12–0·61) than for other patients (0·08, 0·03–0·19).
Interpretation
Our results, which are appropriately controlled for confounding by indication, are consistent with reported declines in rates of AIDS and death in developed countries, and provide a context in which to consider adverse effects of HAART.
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