Discontinuation of primary prophylaxis in HIV-infected patients at high risk of Pneumocystis carinii pneumonia:: prospective multicentre study

Objectives: To assess the safety of discontinuation of primary prophylaxis in HIV-infected patients on antiretroviral combination therapy at high risk of developing Pneumocystis carinii pneumonia. Design: Prospective multicentre study. Patients and methods: The incidence of P. carinii pneumonia after discontinuation of primary prophylaxis was studied in 396 HIV-infected patients on antiretroviral combination therapy who experienced an increase in their CD4 cell count to at least 200 x 10(6)/l and 14% of total lymphocytes; the study population included 191 patients with a history of CD4 cell counts below 100 x 10(6)/l (245 person-years) and 144 patients with plasma HIV RNA above 200 copies/ml (215 person-years). Results: There was one case of Pneumocystis pneumonia, an incidence of 0.18 per 100 person-years [95% confidence interval (CI), 0.005-1.0 per 100 person-years]. No case was diagnosed in groups with low nadir CD4 cell counts (95% CI, 0-1.2 per 100 person-years) or detectable plasma HIV RNA (95% CI, 0-1.4 per 100 person-years). Conclusions: Discontinuation of primary prophylaxis against Pneumocystis pneumonia is safe in patients who have responded with a sustained increase in their CD4 cell count to antiretroviral combination therapy, irrespective of the CD4 cell count nadir and the viral load at the time of stopping prophylaxis. (C) 2001 Lippincott Williams Sc Wilkins.