Predictors of recurrence of multidrug-resistant and extensively drug-resistant tuberculosis

OBJECTIVE: To assess the treatment outcome of the first Green Light Committee (GLC) approved countrywide management of multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) in Estonia and to evaluate risk factors contributing to TB recurrence over 8 years of follow-up. DESIGN: Prospective assessment of MDR- and XDR-TB patients starting second-line anti-tuberculosis drug treatment between 1 August 2001 and 31 July 2003, with follow-up until 31 December 2010. RESULTS: In 211 MDR- and XDR-TB patients, treatment success was 61.1%; 22.3% defaulted, 8.5% failed and 8.1% died. TB recurrence among successfully treated patients was 8.5%, with no significant difference between XDR-TB and MDR-TB. TB recurrence was associated with resistance to all injectables (HR 2.27, 95%CI 1.16-5.06, P = 0.046), resistance to a greater number of drugs (HR 1.35, 95%CI 1.11-1.64, P = 0.003), and sputum smear positivity (HR 2.16, 95%CI 1.16-4.00, P = 0.016). A history of previous TB treatment was associated with TB recurrence among successfully treated patients (HR 4.28, 95%CI 1.13-16.15, P = 0.032). CONCLUSIONS: The internationally recommended Category IV treatment regimens are sufficiently effective to cure 75% of adherent MDR- and XDR-TB patients. A history of previous treatment, resistance to all injectable agents and resistance to a greater number of drugs increase the recurrence of MDR- and XDR-TB.