[Study of HIV seroprevalence in patients with pulmonary tuberculosis in 1999 in Chad]

Tuberculosis is the most common opportunistic disease occurring in the course of human immunodeficiency virus (HIV) infection. With the development of HIV infection in Chad, tuberculosis has quickly become a major public health concern. The purpose of this cross-sectional study in two tuberculosis centres (Moundou and Ndjamena) was to evaluate HIV seroprevalence, epidemiological characteristics and risk factors in patients with tuberculosis. All patients with positive sputum-smears who had never been treated for tuberculosis previously were eligible. A total of 466 patients (sex ratio M/F: 1.96) were included during the six-month period between January and June 99. Each subject was asked to fill out an anonymous standardized questionnaire with detailed information on demographic characteristics, sexual behavior and other risk factors for HIV infection. Data were compared using the Chi-square test, Student's T test and multivariate analysis (logistic regression). One third (33.2%) of patients was seropositive for HIV-1. Mean age was 31.1 years in HIV-positive group and 33.6 years in the HIV-negative group (p = 0.02). The age groups with the highest risk for HIV were 20-29 years and 30-39 years (p < 0.01). Women were more often seropositive that men (39.5% versus 30.1%; p = 0.04). Seropositive patients were more likely to have multiple sexual partners (mean: 1.76; p < 0.01) and a history of sexually transmitted disease (19.9% versus 8.1%; p = 0.01). The mean age at the time of first sexual relations was 16.3 years in the HIV group and 17.1 years in the control (p < 0.01). The percentage of seropositive patients was 39.6% at Moundou and 29.8% at N'djamena (p > 0.01). Multivariate analysis showed that early age of first sex relation (OR = 0.85; 95% IC: 0.74-0.97), higher number of sexual partners (OR = 1.8; 95% CI: 1.4-2.4) and level of education were strongly correlated with HIV infection. The prevalence of HIV in tuberculosis patients is a good indicator of HIV-infection in developing countries. Prevalence of HIV infection is high in tuberculosis patients in Chad. Surveillance for tuberculosis and AIDS must be strengthened in Chad. Mores cooperation is needed between tuberculosis and AIDS control programs. Emphasis should be placed on screening for tuberculosis, early tuberculosis treatment and diagnosis of HIV in tuberculosis patients.