Natural history of advanced HIV disease in patients treated with zidovudine. The Zidovudine Epidemiology Study Group.

OBJECTIVE: To describe the natural history of advanced HIV disease in patients treated with zidovudine. DESIGN: Longitudinal, observational study. SETTING: Twelve academic and community-based sites. PATIENTS, PARTICIPANTS: Eight hundred and sixty-three patients with AIDS or AIDS-related complex (ARC) with a CD4+ lymphocyte count less than 250 x 10(6)/l, who first received zidovudine between 15 April 1987 and 14 April 1988. MAIN OUTCOME MEASURES: Survival, progression to AIDS and first development of specific opportunistic illness. RESULTS: Median survival after initiation of zidovudine therapy ranged from greater than 900 days in patients with a baseline CD4+ lymphocyte count greater than or equal to 150 x 10(6)/l to 560 days in patients with a CD4+ lymphocyte count less than 50 x 10(6)/1. Other factors associated significantly with poorer survival were diagnosis of AIDS (versus ARC), baseline age greater than or equal to 40 years, hematocrit less than 35%, and diminished functional status. In patients with ARC at enrollment, median time of progression to AIDS ranged from 810 days in patients with a CD4+ lymphocyte count greater than or equal to 150 x 10(6)/l to 310 days in patients with a CD4+ lymphocyte count less than 50 x 10(6)/l. Rates of development of specific opportunistic infections or neoplasms and HIV encephalopathy were determined for different baseline CD4+ lymphocyte count ranges. Myelosuppression was significantly more common in patients with CD4+ lymphocyte counts greater than or equal to 100 x 10(6)/l. Sixty-five per cent of patients with a CD4+ lymphocyte count greater than or equal to 100 x 10(6)/l and 51% with a CD4+ lymphocyte count less than 100 x 10(6)/l continued to receive zidovudine 2 years after starting therapy. CONCLUSIONS: We describe the natural history of a cohort of patients treated with zidovudine for advanced HIV disease. These CD4+ lymphocyte count-stratified estimates of disease progression should provide prognostic information useful in the clinical management of advanced disease and the design of future studies.