Predictors of tuberculosis treatment success under the DOTS program in Namibia

Objectives: Optimal treatment success rates are critical to end tuberculosis in Namibia. Despite the scale-up of high quality directly observed therapy short-course strategy (DOTS) in Namibia, treatment success falls short of the global target of 90%. The objective of this study was to ascertain the predictors of treatment success rates under DOTS in Namibia to provide future direction. Methods: A nation-wide comparative analysis of predictors of treatment success was undertaken. Tuberculosis cases in the electronic tuberculosis register were retrospectively reviewed over a 10-year period, 2004-2016. The patient, programmatic, clinical, and treatment predictors of treatment success were determined by multivariate logistic regression modeling using R software. Results: 104,603 TB cases were registered at 300 DOTS sites in 37 districts. The 10-year period treatment success rate was 80%, and varied by region (77.2%-89.2%). The patient's sex and age were not significant predictors. The independent predictors for treatment success as were: Region of DOTS implementation (p=0.001), type of directly observed treatment (DOT) supporter (p<0.001), sputum conversion at 2 months (p=0.013), DOT regimen (p<0.001), cotrimoxazole prophylaxis (p=0.002), and HIV co-infection (p=0.001). Conclusion: Targeted programmatic, clinical and treatment interventions are required to enhance DOTS treatment success in Namibia. These are now ongoing.