High incidence of multidrug-resistant tuberculosis in Bhutan: A cohort study based on national TB surveillance data

Objectives: The emergence of multidrug-resistant tuberculosis (MDR-TB) has made the elimination of TB difficult. Currently, there are limited data on MDR-TB and other drug-resistant TB in Bhutan. We aimed to estimate the incidence and explore the potential risk factors associated with MDR/pre-extensively drug-resistant (pre-XDR)-TB using comprehensive national TB data.

Methods: We used the data from the Tuberculosis Information Surveillance System of the National Tuberculosis Reference Laboratory to analyze the resistance pattern and epidemiologic data for all TB cases tested for resistance for the year 2018-2021. Multiple logistic regression was performed to identify risk factors associated with MDR/pre-XDR-TB.

Results: Of the 2,290 samples tested for drug resistance, 10.6% (n = 243) was MDR-TB, 3.5% (n = 81) was isoniazid-resistant TB, and 0.61% (n = 14) was pre-XDR-TB. A high incidence of MDR/RR-TB/pre-XDR-TB was documented among patients in Thimphu, Samtse, and Sarpang districts. MDR/pre-XDR-TB was more likely documented among patients aged 18-39 years (adjusted odds ratio [aOR] 2.79; 95% confidence interval [CI] 1.46-6.07), female sex (aOR 1.37; 95% CI 1.01-1.86), and patients previously treated for TB (aOR 2.98; 95% CI 1.99-4.42).

Conclusions: Given the high burden of MDR-TB in some districts, decentralization of diagnostic facilities for more rapid characterization could improve early recognition of drug-resistant cases and assist in management. Comprehensive follow-up and monitoring of high-risk groups should be performed.