Long-term follow-up of zidovudine therapy in asymptomatic HIV infection: results of a multicenter cohort study. The Italian Zidovudine Evaluation Group.
In 1990 the results of a placebo-controlled study conducted within the AIDS Clinical Trials Group (ACTG 019) showed that in the short term, zidovudine was effective in slowing progression to advanced disease in HIV-infected asymptomatic patients with low CD4 cell counts. More recently, the preliminary results of the Concorde Trial suggested that while the data at 1 year agreed with those of ACTG 019, no sustained clinical benefit was detectable at 3 years for early versus deferred therapy. Therefore, the length of the clinical usefulness of zidovudine in this population is still to be determined. We evaluated the 2-year outcome of zidovudine therapy in asymptomatic patients through the prospective follow-up of a cohort of 936 subjects with low CD4+ (< 500/mm3) counts who strictly satisfied, at enrollment, the inclusion and exclusion criteria of the ACTG 019 trial. The clinical end point of the analysis was the development of AIDS. The majority (72.2%) of the individuals in the cohort acquired HIV infection through intravenous drug use; 26.6% were women. The median baseline CD4 cell count was 308/mm3. At 55 weeks of mean follow-up, the progression rate to AIDS (3.2 events per hundred person-years) appears to be comparable to that already reported at the same mean follow-up time for the ACTG 019 zidovudine-treated asymptomatic patients. After 124 weeks of mean follow-up, the overall rate of progression to AIDS was 5.2 per hundred person-years.(ABSTRACT TRUNCATED AT 250 WORDS)