Romanowski K, et al. - Authors here investigated treatment outcomes of isoniazid (INH) resistant tuberculosis (TB) patients, treated under programmatic conditions in British Columbia, Canada. The treatment outcomes raised concerns about current recommendations for INH resistant TB treatment. There were only a small proportion of patients who completed the recommended treatment regimens. They recommended high-quality studies to confirm the effectiveness of standardized regimens are urgently needed, with special consideration given to trials utilizing fluoroquinolones.

Methods

• Retrospective review of medical charts was performed for cases of culture-confirmed INH mono-resistant TB reported to the BC Centre for Disease Control (BCCDC) from 2002 to 2014.
• Analysis was done for treatment regimens, patient and strain characteristics, and clinical outcomes.

Results

• The analysis included 165 cases of INH mono-resistant TB; there were over 30 different treatment regimens prescribed.
• Median treatment duration of 10.5 months (IQR 9–12 months) was evident; extended treatment, beyond 12 months, was provided to 26 patients (15.8%).
• There were 56 patients (22.6%) who experienced an adverse event which led to drug regimen modification.
• Overall, a successful treatment outcome was achieved in 140 patients (84.8%) while 12 (7.2%) had an unsuccessful treatment outcome of failure (n = 2; 1.2%), relapse (n = 4; 2.4%) or all cause mortality (n = 6; 3.6%)