Discontinuation of Pneumocystis carinii pneumonia prophylaxis after start of highly active antiretroviral therapy in HIV-1 infection. EuroSIDA Study Group

BACKGROUND: Highly active antiretroviral therapy (HAART) has improved rates of CD4-lymphocyte recovery and decreased the incidence of HIV-1-related morbidity and mortality. We assessed whether prophylaxis against Pneumocystis carinii pneumonia (PCP) can be safely discontinued after HAART is started.

METHODS: We investigated 7333 HIV-1-infected patients already enrolled in EuroSIDA, a continuing prospective observational cohort study in 52 centres across Europe and Israel. We did a person-years analysis of the rate of discontinuation of PCP prophylaxis and of the incidence of PCP after the introduction of HAART into clinical practice from July, 1996.

FINDINGS: The rate of discontinuation of primary and secondary PCP prophylaxis increased up to 21.9 discontinuations per 100 person-years of follow-up after March, 1998. 378 patients discontinued primary (319) or secondary (59) prophylaxis a median of 10 months after starting HAART. At discontinuation for primary and secondary prophylaxis, respectively, the median CD4-lymphocyte counts were 274 cells/microL and 270 cells/microL, the median plasma HIV-1 RNA load 500 copies/mL, and the median lowest recorded CD4-lymphocyte counts 123 cells/microL and 60 cells/microL. During 247 person-years of follow-up, no patient developed PCP (incidence density 0 [95% CI 0-1.5]).

INTERPRETATION: The risk of PCP after stopping primary prophylaxis, especially in patients on HAART with a rise in CD4-lymphocyte count to more than 200 cells/microL, is sufficiently low to warrant discontinuation of primary PCP prophylaxis. Longer follow-up is needed to confirm a similarly low risk for stopping secondary PCP prophylaxis.