Scale-up of 99DOTS for TB treatment supervision: an interrupted time series analysis

Digital adherence technologies such as 99DOTS are being scaled-up for TB treatment despite limited evidence of their effectiveness and concerns about accessibility. We evaluated the reach and effectiveness of 99DOTS during its scale-up in Uganda.We included all adults initiating drug-susceptible pulmonary TB treatment between August 2019 to June 2021 at 12 99DOTS-naïve health facilities (n = 3,526). Using an interrupted time series design, we compared the proportion with treatment success (primary outcome) and enrolled on 99DOTS in the 9 months before and 12 months after implementing an 'enhanced 99DOTS' intervention. This included providing low-cost phones to people with TB when needed, task shifting monitoring and support to community health workers, and automated task lists. Treatment data were derived from routine TB treatment registers.The proportion enrolled on 99DOTS post-intervention was high (87.2%) and had a slight upward trend (proportion ratio 1.01, 95% CI 1.00-1.01). Treatment completion remained similar across periods (89.8% post-intervention vs. 87.1% pre-intervention). There was no immediate level or slope change in treatment success following the intervention.With appropriate implementation supports, 99DOTS can have high uptake without negatively impacting treatment outcomes. Equity in access should be prioritized during implementation..