Treatment Outcomes with Fluoroquinolone-Containing Regimens for Isoniazid-Resistant Pulmonary Tuberculosis

Abstract

Resistance to isoniazid (INH) is the most common form of drug resistance in pulmonary tuberculosis (TB). Although fluoroquinolones (FQs) are recommended to strengthen treatment regimens for INH-resistant pulmonary TB, few studies have evaluated the clinical efficacy of FQ-containing regimens in patients with INH-resistant pulmonary TB. A retrospective cohort study of 140 patients with INH-resistant pulmonary TB was performed between 2005 and 2012. We evaluated whether FQ-containing regimens yielded improved treatment outcomes for patients with INH-resistant pulmonary TB. Overall, favorable outcomes were achieved in 128 (91.4%) patients. Unfavorable outcomes occurred in 12 patients (8.6%), including 7 with treatment failure (5.0%) and 5 with relapse after initial treatment completion (3.6%). FQs, such as levofloxacin and moxifloxacin, were given to 75 (53.6%) patients. Favorable treatment outcomes were more frequent for patients who received FQs (97.3% [73/75 patients]) than for those who did not receive FQs (84.6% [55/65 patients]) (P = 0.007). Patients who did not receive FQs were more likely to develop treatment failure (9.2% [6/65 patients] versus 1.3% [1/75 patients]) (P = 0.049) than patients who received FQs. The adjusted proportion of unfavorable outcomes was significantly higher among patients who did not receive FQs (8.8%; 95% confidence interval [CI], 3.3 to 21.5%) than among those who did receive FQs (1.5%; 95% CI, 0.3 to 7.7%) (P = 0.037). These results suggest that the addition of FQs can improve treatment outcomes for patients with INH-resistant pulmonary TB.