The study is the most detailed effort thus far to measure the effectiveness of potent antiretroviral therapy outside clinical trials, where both physicians and patients must adhere to a strict protocol. Potent antiretroviral therapy significantly extends AIDS-free time and survival of people with HIV infection, despite the difficulty of staying on the complex treatment regime and the existence of side effects. The study has followed more than 5,000 gay men from Baltimore, Chicago, Pittsburgh and Los Angeles since 1984. For the study of potent antiretroviral therapy, Detels and his colleagues analyzed the experiences of 536 men who became infected with HIV after the start of the MACS study, of whom 231 developed AIDS and 200 died. Researchers compared the experiences of the men from July 1995 to July 1997, when the potent antiretroviral therapy was available, to earlier periods when the therapy was not available.
Researchers say their findings probably underestimate the true effectiveness of the drugs.
Only about half of the men in the July 1995 to July 1997 study period took the antiretroviral therapy and only on average for about half of the two-year study period. This allowed researchers to use sophisticated statistical strategies that could compensate for different durations of HIV infection in men studied before and after potent antiretroviral therapy became available. Potent antiretroviral therapy is shown to lengthen the average time without an AIDS-defining illness by 63 percent. The UCLA study is the first one examining the impact of potent antiretroviral therapy, as used in the community, on promoting the recovery of the immune system. The study also underscores the important role that observational studies such as the MACS can play in evaluating the overall effectiveness of new therapies, which clinical trials cannot do.