Incidence of primary opportunistic infections in two human immunodeficiency virus-infected French clinical cohorts

Background Clinical guidelines for the prevention of opportunistic infectio ns in human immunodeficiency virus (HIV)-infected individuals have been dev eloped on the basis of natural history data collected in the USA. The objec tive of this study was to estimate the incidence of primary opportunistic i nfections in HIV-infected individuals in geographically distinct cohorts in France. Methods We conducted our study on 2664 HIV-infected patients from the Tourc oing AIDS Reference Centre and the hospital-based information system of the Groupe d'Epidemiologie Clinique du SIDA en Aquitaine enrolled from January 1987 to September 1995 and followed through December 1995. We estimated: ( 1) CD4-adjusted incidence rates of seven primary opportunistic infections i n the absence of prophylaxis for that specific infection or any antiretrovi ral drugs other than zidovudine; and (2) CD4 lymphocyte count decline. Results The highest incidence rates for all opportunistic infections studie d occurred in patients with CD4 counts <200/ <mu>l. With CD4 counts <50/<mu >l, the most common opportunistic infections were toxoplasmic encephalitis (12.6 per 100 person-years) and Pneumocystis carinii pneumonia (11.4 per 10 0 person-years). Mycobacterium tuberculosis was the least common opportunis tic infection (<5.0/100 person-years). Even with CD4 counts >300/mul, cases of Pneumocystis carinii pneumonia and toxoplasmic encephalitis were report ed. The mean CD4 lymphocyte decline per month was 4.6 cells/mul. There was a significant association between MV risk behaviour and the incidence of cy tomegalovirus infection, between calendar year and the incidence of Pneumoc ystis carinii pneumonia, toxoplasmic encephalitis and Candida esophagitis, and between geographical area and the incidence of Pneumocystis carinii pne umonia and cytomegalovirus infection. Conclusions Geographical differences exist in the incidence of HIV-related opportunistic infections. These results can be used to define local priorit ies for prophylaxis of opportunistic infections.