The impact of the adoption of DOTS (directly observed therapy, short-course), the World Health Organization’s (WHO) tuberculosis control strategy in 187 WHO member states, has been investigated using a new approach. The study, Has the DOTS strategy improved case finding or treatment success? An empirical assessment, found that implementation of the DOTS program led to significant improvements in treatment success rates. The work was done in collaboration with scientists at Harvard University and the University of California San Francisco School of Medicine.
The researchers found DOTS population coverage had a significant effect on overall treatment success rates, such that countries with full DOTS coverage benefit from at least an 18% increase in treatment success. However, the study could not identify which element of the DOTS package was effective in increasing the treatment success rate. DOTS program variables, including population coverage and treatment success rate, had no statistically significant impact on case notification, and by inference, case detection.
Researchers studied the effects of DOTS using time series cross-sectional methods. They first estimated the impact of DOTS expansion on case detection, using reported case notification data and controlling for other determinants of change in notifications, including HIV prevalence, gross domestic product, and country-specific effects. The effect of DOTS expansion on treatment success was then estimated.
Tuberculosis, the ninth leading cause of death and disability worldwide, remains a major global health problem, despite the implementation of DOTS. There is a lack of empirical evidence that DOTS reduces tuberculosis burden; as a result, its place in the future of global tuberculosis control efforts is uncertain. This study investigates the impact of the expansion of DOTS on tuberculosis case finding and treatment success using empirical data. This research is part of ongoing work by IHME to assess the impact of policies and interventions to understand the progress being made in health.
Recommendations for future work
The finding that DOTS expansion had no effect on case detection is less optimistic than previous analyses. Future studies should identify better epidemiological and program data to facilitate future monitoring and evaluation efforts. Additionally, the absence of clear evidence on the effectiveness of existing techniques suggests that broadly-applicable new strategies for actively detecting new cases of tuberculosis are urgently needed.