[Multicenter French cohort of adults with HIV infection. Description and course after 4 years of follow-up. SEROCO].

Objectives: A prospective multicentric epidemiological study (SEROCO) of subjects with a diagnosis of human immunodeficiency virus (HIV) infection was started on January 1, 1988 in order to better understand the natural history of HIV infection and factors related to outcome. Observations after 4 years of follow-up are reported here.
Methods: After authorization by the French national ethics committee and the national commission for personal freedom, 18 French centres included non-haemophiliac volunteers who were asymptomatic, had had non anti-HIV treatment and whose HIV positivity had been known less than 1 year at inclusion. These last three criteria were not required for patients whose precise date of contamination was known within a range of +/- 3 months.
Results: On July 15, 1992, there were 1453 infected subjects in the cohort (1063 males, 417 females; age range at inclusion 18-75 years; mean age 31.3 +/- 9.4). Globally, 2.7% of the subjects were symptomatic at inclusion. Mean CD4 lymphocyte count at inclusion was 508/mm3. Clinically, 51.5% of the patients had a history of sexually transmitted disease at inclusion. After 4 years (on July 15, 1992) mean follow-up was 28 +/- 12.9 months for a total of 3428 patient-years. Disease progression to stage IV was observed in 439 patients including 202 who developed the acquired immuno-deficiency syndrome (AIDS). Among these 202 patients, 113 had died at the end-point of this report. The first manifestation of AIDS was Kaposi sarcoma in 44, pulmonary pneumocystosis in 38 and cerebral toxoplasmosis in 27. The probability of developing AIDS was calculated at 13.9% at 5 years, 27.7% at 7 years and 33.7% at 10 years. The probability of a CD4 count below 200/mm3 was 32.7, 55.6 and 67% at 5, 7 and 10 years respectively. For patients with a CD4 count below 200, the probability of developing AIDS was 18% at 1 year, 39% at 2 years and 51% at 3 years.
Conclusions: SEROCO has been a most useful prospective epidemiological tool due to the diversity of the subjects included. The observed natural history of HIV infection will lead to specific research projects aimed at better understanding the disease process.