Risk factors for relapse in human immunodeficiency virus type 1 infected adults with pulmonary tuberculosis

Uganda has high incidence rates of tuberculosis (TB) and HIV-1 infection. In that context researchers at the Uganda-Case Western Reserve University Research Collaboration in Kampala investigated which clinical microbiologic and radiographic factors are associated with the risk of relapse in HIV-infected adults treated for initial episodes of pulmonary TB. Findings are based upon 119 patients aged 18-50 years who completed therapy and the median follow-up duration for all subjects was 22.3 months. Subjects in this randomized prospective clinical trial were treated with either 2 months of daily streptomycin thiacetazone (T) and isoniazid (H) followed by 10 months of daily T and H or 2 months of daily isoniazid rifampicin (R) and pyrazinamide followed by 7 months of daily H and R. 10 patients relapsed a median of 12.7 months (range 5-33.4 months) after the end of therapy 7 of whom were initially treated with the T-containing regimen. Each relapse case was matched to 4 controls by length of follow-up after initial TB treatment. Univariate analysis found that the risk of relapse was associated with treatment with the T-containing regimen being age 30 years or older and irregular compliance. Baseline anergy on Mantoux tuberculin skin testing cavitary disease radiographic extent of disease and sputum bacillary burden 2-month culture negativity and residual cavitary disease at the end of treatment did not differ between relapses and controls.