Effectiveness of the community-based DOTS strategy on tuberculosis treatment success rates in Namibia

Setting: Directly Observed Treatment Short-course is a key pillar of the global strategy to end tuberculosis. Objective: The effectiveness of community-based compared to facility-based DOTS on tuberculosis treatment success rates in Namibia was assessed. Methods: Annual tuberculosis treatment success, cure, completion and case notification rates were compared between 1996 and 2015 by interrupted time series analysis. The intervention was the upgrading by the Namibian government of the tuberculosis treatment strategy from facility-based to community-based DOTS in 2005. Results: The mean annual treatment success rate during the pre-intervention period was 58.9% (range: 46-66%) and significantly increased to 81.3% (range: 69-87%) during the post-intervention period. Before the intervention there was a non-significant increase (0.3%/year) in the annual treatment success rate. After the intervention, the annual treatment success rate increased abruptly by 12.9% (p <0.001) and continued to increase by 1.1%/year thereafter. The treatment success rate seemed to have stagnated at approximately 85% at the end of the observation period. Conclusion: Expanding facility-based DOTS to community-based DOTS significantly increased the annual treatment success rates. However, the treatment success rate at the end of the observation period had stagnated below the targeted 95% success rate.