Bhutan study finds age and pulmonary TB raise treatment risk

Tuberculosis remains a major public health concern in Bhutan, and making sure people complete effective treatment is central to controlling the disease. To fill gaps in knowledge about how well treatment is working in the country, Thinley Dorji and colleagues examined national TB surveillance records. They used a retrospective cohort study design, analysing patient data collected over 2018-2021 and provided by the National Tuberculosis Reference Laboratory, Royal Centre for Disease Control. The goal was straightforward: measure treatment outcomes across the national programme and identify which groups were more likely to have an unsuccessful result. By looking back over several years of routine records, the researchers were able to capture the experience of thousands of patients treated in Bhutan’s public system. Their work focuses on outcomes recorded in the national dataset and uses statistical analysis to pinpoint factors that are associated with treatment problems, offering a broad, national view rather than a single-hospital snapshot. The study provides a clear basis for targeting follow-up and support where it is most needed.

The research team analysed records for 3,619 patients who received TB treatment from 2018 to 2021. Of those, 52.4% were pulmonary bacteriologically confirmed TB (PBC) and 27% were extra-pulmonary clinically diagnosed. Treatment outcome was recorded for 3,330 patients: 96.2% had a successful outcome (44.4% cured and 51.7% completed treatment) while 3.8% had an unsuccessful outcome (2.8% died; 0.4% lost to follow up; 0.7% treatment failure). To identify which factors predicted an unsuccessful outcome the authors ran Univariate and multiple logistic regression analyses. Multiple logistic regression showed that patients older than 60 years of age (aOR 4.3; 95% CI 2.11 – 10.1; p-value <0.001), those diagnosed in 2021 (aOR 1.73; 95% CI 1.03 – 2.96; p-value 0.041), and those with pulmonary bacteriologically confirmed TB (PBC) (aOR 2.33; 95% CI 1.49-3.8; p-value <0.001) were more likely to have an unsuccessful treatment outcome.

The findings carry practical implications for TB control in Bhutan. The overall success rate of 96.2% exceeds the global target of 90%, showing the national programme is performing well for the majority of patients. Still, the study highlights small but important gaps: older people and those with pulmonary bacteriologically confirmed disease face higher risk of death, loss to follow-up or treatment failure. That suggests programs should prioritise active follow-up, closer monitoring and perhaps tailored support for these groups to raise their chances of success. The authors also call for in-depth studies to understand the circumstances behind treatment failures and deaths, so that specific interventions can be designed. In short, the national picture is encouraging, but targeted action on higher-risk groups could further reduce the remaining burden of unsuccessful treatment.