Study of relapse and failure cases of CAT I retreated with CAT II under RNTCP--an eleven year follow up.

To analyse the treatment outcome of Cat I smear positive relapse and failure cases and their fate when treated with Cat II regimen under RNTCP. All Cat I smear positive relapse and failure TB patients treated with Category II regimen from 1994 to 2005 in a chest clinic of Delhi were analysed in this retrospective study. The re-treatment outcome data for relapse and failure cases of Cat I when treated with Cat II regimen was reviewed. The study population included 5576 registered as Cat I sputum positive cases in Gulabi Bagh chest clinic from 1994 to 2005. A total of 190 (3.4%) failed on Cat I regimen. Further out of 4905 (87.9%) successfully treated Cat I patients, 442 (9%) presented as relapses. The treatment success rate for relapse and failure cases of Cat I when subsequently treated with Cat II regimen were 76.4% and 48.8% respectively, with a significantly higher failure rate (27.6%) among Cat I failures subsequently treated with Cat II regimen. The failure cases of Cat I subsequently treated with Cat II were observed to have a significantly lower success rates (p < 0.05) as compared to relapse cases. The need for reappraisal of Cat II re-treatment regimen for failure cases among Cat I is suggested.