Objective: To analyse treatment outcomes by subcategory of tuberculosis (TB) retreatment cases.
Methods: All TB patients treated with the Category II regimen from 1996 to 2003 in Morocco were enrolled in this retrospective study. For each cohort, the retreatment outcome data were analysed as a whole and by the following sub-categories: 1) cases who relapsed after one course of anti-tuberculosis treatment; 2) cases who failed the Category I regimen; and 3) cases who interrupted one course of anti-tuberculosis treatment.
Results: The study population included 14 635 retreatment patients, among whom 81.7% were TB relapse cases, 5.2% had failed the Category I regimen and 13.1% were defaulters. The average treatment success rates were respectively 74.8% (range 71.8-76.6), 58.0% (range 52.4-74.0) and 51.4% (range 46.4-55.6) among relapse, failure and default cases. Failure and default rates were significantly higher (P < 0.001) among patients who failed Category I treatment and among those who defaulted, respectively.
Conclusions: TB cases who fail the Category I regimen should systematically receive drug susceptibility testing, while defaulters should be given support to improve treatment adherence. Stratified cohort analysis by subcategory of retreatment has been shown to be useful for evaluating the performance of TB control programmes.