Setting: National Tuberculosis Programme, the Philippines.
Objective: To compare treatment outcomes of Category I and Category II regimens among mono- and/or polyresistant tuberculosis (TB) cases under programme conditions.
Design: Retrospective cohort analysis of pulmonary TB patients from two data sets from the National Drug Resistance Survey and the Programmatic Management of Drug-resistant Tuberculosis by linking drug resistance patterns with treatment outcomes.
Results: Of 288 Category I patients, 193 were isoniazid (INH) resistant, 42 were either ethambutol (EMB) or streptomycin (SM) resistant, and 53 were resistant to a combination of two or all three TB drugs. Of 138 Category II patients, 92 were INH-resistant, 9 were either EMB- or SM-resistant, and 37 were poly-resistant. Respectively 206 (87.7%) and 41 (77.4%) mono- and poly-resistant patients treated with the Category I regimen achieved significantly higher successful treatment outcomes, in comparison to respectively 60 (59.4%) and 15 (40.5%) mono- and poly-resistant patients treated with the Category II regimen.
Conclusion: The Category II regimen produced poor outcomes, whereas the Category I regimen achieved a treatment success rate of more than 85% among new patients with the same drug resistance patterns. The poor outcomes of the Category II regimen could be attributed to other factors such as patient behaviour and comorbidities, rather than drug resistance.