Factors influencing treatment outcomes in patients with isoniazid-resistant pulmonary TB.

Abstract

<b>INTRODUCTION:</b> Patients with isoniazid (H, INH) resistant pulmonary TB but undetected rifampicin (R, RIF) resistance are treated with a 6-month regimen of levofloxacin-RIF-ethambutol-pyrazinamide (6LvxREZ) under India´s National TB Elimination Programme (NTEP).<b>OBJECTIVE:</b> To describe the profile of and treatment outcomes in patients with pulmonary INH-resistant (INH^R) TB initiated on TB treatment, and identify factors associated with unfavourable treatment outcomes (died, failed, treatment changed, lost to follow-up).<b>METHODS:</b> This was a retrospective analysis of NTEP database (Ni-kshay) on pulmonary INH^R TB patients initiated on treatment with "H mono/poly regimen" (6LvxREZ) between July 2019 and June 2020 with documented treatment outcomes. Proportions with 95% confidence interval (CI) was calculated and logistic regression analysis was performed.<b>RESULTS:</b> Of the 11,519 patients with pulmonary INH^R TB, 9,440 (82%) had treatment success (55.1% cured, 26.9% treatment completed). Unfavourable treatment outcome was observed in 1,901 (16.5%). Male sex, tobacco and alcohol use, HIV reactive status were associated with unfavourable treatment outcome. Patients with <i>kat</i>G mutations and resistance to fluoroquinolones were likely to have poor treatment outcomes.<b>CONCLUSION:</b> A levofloxacin-based regimen offers a treatment success rate of 82% in patients with pulmonary INH^R TB. Sex-specific strategies, interventions to address smoking and alcohol use, focus on HIV-reactive patients and optimising treatment regimens based on drug susceptibility should be considered for improving treatment outcomes.