Toxoplasma gondii infection in advanced HIV infection.

OBJECTIVE:

To study Toxoplasma encephalitis (TE) in advanced HIV infection, including predictive factors, possible prophylactic regimens and impact on survival.

DESIGN:

Epidemiological analysis of data collected prospectively during the Alpha study, a double-blind, randomized clinical trial, comparing two doses of dideoxyinosine in patients with advanced HIV disease.

PATIENTS:

First episode of TE occurred in 75 out of 499 patients participating in the trial.

METHODS:

Kaplan-Meier estimates and semi-parametric Cox's model were used.

RESULTS:

A low CD4 cell count and a positive Toxoplasma serology were strongly predictive of the occurrence of TE. In patients with CD4 counts < 100 x 10(6)/l and a positive Toxoplasma serology at entry to the study, the 12-month TE incidence was 25.4%. Patients who were receiving at entry any of the following potentially antitoxoplasmic drugs: trimethoprim-sulphamethoxazole, pyrimethamine, dapsone, pyrimethamine-sulphadoxine or sulphadiazine, had a lower TE incidence than those who were not; 6.2 versus 18.8%, respectively (P < 0.001). The rate of survival 12 months after TE was 29.6%. Even after adjusting the major prognostic covariates, TE was predictive of death (P < 0.001; relative risk, 1.8).

CONCLUSIONS:

The high HIV incidence, morbidity and mortality in high-prevalence areas suggests that primary prophylaxis should be given in patients at high risk for toxoplasmic reactivation.