Cotrimoxazole prophylaxis is associated with reduced risk of incident tuberculosis in participants in the Swiss HIV Cohort Study

Cotrimoxazole reduces mortality in HIV-infected adults with tuberculosis (TB), and in vitro data suggest potential anti-mycobacterial activity of cotrimoxazole. We aimed to evaluate whether prophylaxis with cotrimoxazole is associated with a decreased risk of incident TB in SHCS participants. We determined the incidence of TB per 1000 person-years from January 1992 to December 2012. Rates were analyzed separately in participants with current or no previous antiretroviral treatment (ART) using Poisson regression adjusted for CD4 cell count, sex, region of origin, injecting drug use, and age. 13,431 cohort participants contributed 107,549 person-years follow-up; 182 patients had incident TB; 132 (73%) before and 50 (27%) after ART initiation. The multivariable incidence rate ratios for cumulative cotrimoxazole exposure per year for persons with no previous and current ART were 0.70 (95% CI 0.55-0.89) and 0.87 (0.74-1.0) respectively. Cotrimoxazole may prevent the development of TB among HIV-positive persons, especially among those with no previous ART.