Treatment Outcomes for Isoniazid-Resistant Pulmonary Tuberculosis Using a Shorter Regimen at a Tertiary Care Centre from the Western Part of India

Abstract

Background: Drug-resistant tuberculosis has been associated with higher rates of morbidity and mortality. A global total of an estimated 4 lakh people with ‘multidrug resistant/rifampicin resistant’ tuberculosis (MDR/RR-TB) were detected and notified in 2023. In India, 63,929 MDR/ RR TB cases were diagnosed, with 23,019 patients diagnosed with isoniazid (H)-mono/poly drug-resistant tuberculosis (DR-TB).
Objective: This study analyses the outcome of ‘Isoniazid Mono Resistance’ Tuberculosis patients and the adverse drug reaction (ADR) among those put on isoniazid (H) mono/poly regimen treatment.
Method: ‘Isoniazid-mono-poly’ DR TB regimen duration is 6 to 9 months and started according to drug sensitivity testing (DST) among eligible patients. Follow-ups were done every two months for clinical, bacteriological and radiological parameters. Outcomes observed were cure, treatment completed, treatment failure, died, lost to follow-up, not evaluated, switch to another regimen and transfer out, etc., as per standard protocol.
Results: 88 isoniazid-mono/poly patients were enrolled over the last two years. There were 62 male and 26 were females. Outcome for isoniazid mono/poly regimen was cure among 40 (45.5%), treatment completed in 34 (38.6%), lost to follow up in 2 (2.3%), treatment failure in 1 (1.1%), died in 9 (10.2%) and switched to another regimen in 2 (2.3%). The prevalence of katG mutation (High level Isoniazid resistance) was more than inhA (Low level Isoniazid resistance). A more favorable treatment outcome was observed among those with minimal/moderate lung disease compared to those with far advance disease with large cavitation (p = 0.029). This was also in line with better sputum conversion.
Conclusion: Treating isoniazid ‘mono-resistant’ TB patients with levofloxacin, rifampicin, ethambutol, and pyrazinamide (LfxREZ) resulted in satisfactory outcomes and low toxicity. Ruling out the isoniazid drug resistance pattern is important for all bacteriologically confirmed TB cases.