Incidence and risk factors for toxoplasmic encephalitis in human immunodeficiency virus-infected patients before and during the highly active antiretroviral therapy era.

The occurrence of toxoplasmic encephalitis (TE) was studied among 19,598 and 17,016 patients enrolled in the French Hospital Database on human immunodeficiency virus whose CD4 cell counts decreased to < or =200x10(6) cells/L before (1992-1995) or after (1996-1998) the availability of highly active antiretroviral therapy, respectively. The incidence of TE decreased from 3.9 cases per 100 person-years in the first period (95% confidence interval [CI], 3.7-4.1) to 1.0 cases per 100 person-years in the second period (95% CI, 0.9-1.1). After adjustment for known risk factors for TE, patients who received cotrimoxazole prophylaxis had a lower risk of TE (adjusted relative hazard, 0.6 and 0.5, respectively, for the first and second periods; P < .001). For patients treated with cotrimoxazole at inclusion, discontinuation of cotrimoxazole increased the risk of TE in both periods (adjusted relative hazard, 4.8 and 4.2, respectively; P < .001). Among patients whose CD4 cell counts increased to > 200 x 10(6) cells/L while undergoing highly active antiretroviral therapy, the incidence of TE was 0.1 cases per 100 person-years (95% CI, 0.0-0.2) and was not increased by discontinuation of cotrimoxazole.