Objective: To determine the incidence of Isospora belli infection in HIV-infected patients in France, and to study risk factors.
Methods: The French Hospital Database on HIV (FHDH) is a prospective cohort study that collects demographic, clinical and therapeutic data on patients managed in 62 hospitals. We reviewed all cases of I. belli infection recorded between 1992 and 2003. We compared the incidence in 1992-1994 [before the use of dual therapy and combination antiretroviral therapy (cART)] and in 1997-2003 (when use of cART was widespread), after stratification for CD4 cell count (< 50, 50-99, 100-199 and > 200 cells/microL).
Results: A total of 164 patients had I. belli infection either at enrollment (n=71) or during follow up (n=93). During the study period, I. belli infection tended to occur less frequently during follow up, and to be diagnosed mainly at database enrollment. The incidence of I. belli infection during follow up fell by 79% [relative hazard (RH) 0.21; 95% confidence interval (CI) 0.13-0.33] in the cART period compared with the pre-cART period; no such change was noted among patients with CD4 cell counts below 50 cells/microL. In multivariable analysis, the risk of I. belli infection was significantly higher among patients from sub-Saharan Africa (RH 4.3; 95% CI 2.6-7.3). After adjustment for CD4 cell count, patients receiving cotrimoxazole prophylaxis were found to be at a lower risk of I. belli infection (RH 0.3; 95% CI 0.2-0.6).
Conclusions: In France, I. belli infection among HIV-infected patients is now mainly seen in patients from sub-Saharan Africa, who present at an advanced stage.