Twenty years of rifampicin resistance surveillance in Bangladesh: periodic vs. continuous monitoring.

OBJECTIVE: To analyse 20 years of tuberculosis (TB) drug resistance surveillance, comparing conventional periodic random drug resistance surveys with continuous monitoring, in Damien Foundation-supported districts of Bangladesh.

DESIGN: Retrospective study of data on TB drug resistance from five periodic surveys among newly registered patients vs. continuous monitoring of retreatment patients from 1996 to 2016.

RESULTS: Periodic surveys and continuous monitoring showed similar trends in rifampicin (RMP) resistance; with all smear-positives registered as denominator, prevalence in new cases was found to be at approximately the same level as incidence in retreatment cases. Changes in trends observed using continuous monitoring preceded those detected in periodic surveys by a few years. The accurate interpretation of trend changes requires detailed knowledge of changes in treatment regimens, referral criteria, testing methods and operational factors.

CONCLUSION: Low rates of resistance to RMP, isoniazid and the fluoroquinolones were maintained over the two decades, indicating excellent TB programme performance, including highly active standard first- and second-line treatment regimens. Continuous monitoring is feasible, but requires rigorous application of referral guidelines and data maintenance. Contrary to random surveys, continuous monitoring provides early indications of programme performance, essential for individual patient management, and is more efficient and cost-effective.