Clofazimine and QT prolongation in the treatment of rifampicin-resistant tuberculosis: Findings of aDSM in Taiwan

Background

Bedaquiline, delamanid and fluoroquinolones are associated with increased QTcF. Whether clofazimine is associated with QTcF prolongation is less clear.

Methods

All patients with rifampicin-resistant TB enrolled between May 2017 and Dec 2019 were included. ECGs were performed at baseline, month 1, month 3 and month 6 for patients treated with conventional regimens, and at additional timepoint for patients treated with bedaquiline, delamanid and short regimen. We estimated the maximum increase of QTcF and constructed cox proportional hazards models to assess factors associated with QTcF≥501ms.

Results

Among 321 patients, 59 (18.4%) patients had QTcF≥501ms during a mean follow-up of 242 days (median 189, range 4–1091). The median maximum increase of QTcF was 43.4 ms (IQR 31.3–65.9) in patients treated with clofazimine. Treatment with clofazimine was significantly associated with QTcF≥501ms as compared to without clofazimine (adjusted hazards ratio (adjHR) 4.35, 95% confidence interval (CI) 2.01–9.44). Among patients not treated with bedaquiline and delamanid, those treated with clofazimine and a fluoroquinolone (adjHR 3.43, 95% CI 1.61–7.34) and those treated with clofazimine and high dose moxifloxacin (adjHR 6.54, 95% CI 2.43–17.60) had a significantly higher risk of QTcF≥501ms as compared to those treated with a fluoroquinolone without other QTcF prolonging agents. Four (1.6%) patients had documented ventricular tachycardia, in which one was Torsade de pointes. One patient was found to have sudden death during hospitalization.

Conclusions

Clofazimine was significantly associated with an increased risk of QTcF prolongation. QTcF≥501ms was potentially associated with fatal event and needed to be managed cautiously.