Evaluation of treatment regimens and long-term clinical outcomes in patients with isoniazid-resistant pulmonary tuberculosis: a 5-year follow-up

BACKGROUND/AIM: Considering its early bactericidal activity, isoniazid (H) is an important first-line agent in tuberculosis (TB) treatment. The aim of this study was to evaluate the treatment regimens and results of H-resistant pulmonary TB patients. MATERIALS AND METHODS: We retrospectively evaluated treatment regimens and results of 188 H-resistant pulmonary TB patients who were treated in our center between January 2015 and December 2017. Treatment regimens applied were noted and treatment outcomes were recorded. The long-term results were evaluated. RESULTS: Totally 174 (92.6%) of 188 patients with H-resistant pulmonary TB achieved treatment success. Ninety-seven patients (51.6%) were cured and 77 patients (41.0%) completed treatment. Five patients (2.7%) had treatment failure. Four patients (2.1%) having treatment success relapsed during one-year follow-up. Eighteen patients (9.6%) had unfavorable outcomes, including treatment failure in five (2.7%), death in nine (4.8%), and relapse in four patients (2.1%). The treatment success rate was found to be statistically higher in group 1 (9-month regimen 2HREZ/7HRE) compared with those in group 2 (9HREZ) (97.4% vs. 85.9%; p = 0.010). Group 3 (HREZFQ) and group 1 had statistically significant favorable outcomes, compared to group 2 (group 2 vs. group 3, p = 0.048; group 1 vs. group 2, p = 0.022). Interestingly, no relapse and acquired rifampicin resistance in patients occurred who received an FQ-containing regimen. CONCLUSION: Our study results show higher treatment success and positive results with the treatment regimen containing FQ and that treatment with HREZ for nine months is associated with a lower treatment success rate.