Equity, cost and disability adjusted life years of tuberculosis treatment supported by digital adherence technologies and differentiated care in Ethiopia: a trial-based distributional cost-effectiveness analysis
Authors: Foster Nicola , Tadesse Amare W , Belachew Mahilet , Sahlie Mamush , McQuaid Christopher Finn , Goscé Lara , Bedru Ahmed , Abdurhman Tofik , Umeta Demekech G , Shiferaw Amanuel , Weldemichael Gedion T , Janfa Taye Letta , Madden Norma , Charalambous Salome , van Rest Job , van Kalmthout Kristian , Jerene Degu , Fielding Katherine L 
Published: July 2024

Background

Evidence of the cost-effectiveness of digital adherence technologies (DATs) for supporting tuberculosis treatment has been inconclusive and primarily omitted patient-incurred costs. We aimed to assess the societal costs, equity impact and cost-effectiveness of DATs and differentiated care compared to routine care in Ethiopia.

Methods

We conducted a distributional cost-effectiveness analysis using data from the cluster randomised trial that evaluated the implementation of labels and pillbox followed by differentiated care to support tuberculosis treatment adherence in 78 health facilities in Ethiopia. We estimated the costs, cost per disability-adjusted life year (DALYs) averted and equity impact of the implementation of the DATs interventions. Costs and DALYs were estimated at a participant level based on patient events collected during the trial and the trial endpoints for intention-to-treat population. Uncertainty in cost-effectiveness estimates were assessed by plotting cost-effectiveness acceptability frontiers. The trial is registered with Pan African Clinical Trial Registry (PACTR) PACTR202008776694999, registered on 11 August 2020 athttps://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=12241and has been completed.

Findings

The mean total societal treatment cost per trial participant was US$507 (95%CI: 458; 555) in the SOC, US$196 (95%CI: 190; 218) in the labels and US$206 (95%CI: 167; 213) in the pillbox study arms. We estimated that there was a 49-56% probability that the implementation of the DAT interventions, would improve the cost-effectiveness of tuberculosis treatment at a cost-effectiveness threshold of US$100. There was no difference in DALYs between socio-economic position groups (p=0.920), however, patient costs were less concentrated among those relatively poor in the intervention arms – labels (illness concentration index [ICI]=0.03 (95%CI: 0.01; 0.05)) and pillbox (ICI=0.01 (95%CI:-0.01; 0.02)); compared to the SOC (ICI=-0.05 (95%CI: -0.07; -0.02). Between group comparison (p<0.001).

Interpretation

DAT interventions were cost-saving and reduced the inequitable distribution of patient costs compared to the SOC. This highlights the potential value of interventions that reduce health service visits in improving the equitable distribution of health services.

Funding

Unitaid (Grant Agreement Number: 2019-33-ASCENT).

Research in context

Evidence before this study

In November 2022, we searched PubMed and MedRxiv for English-language studies published between January 2000 and current, using the terms “tuberculosis” AND “cost” AND (“Digital Adherence Technologies” OR “DATS” OR “99DOTS” OR “Pillbox”). This search was repeated as part of a systematic review in April 2023 followed by an update in May 2024. Twenty-nine relevant studies have been identified, estimating the costs of DATS, though many did not assess the full economic costs of implementation. Only two studies included an assessment of patient-incurred costs, and none considering the equity distribution of costs or outcomes using an asset-based index.

Added value of this study

The ASCENT study provides robust evidence using a comprehensive economic evaluation framework, that DATs decreased the cost of tuberculosis treatment in Ethiopia for a cohort of adults with pulmonary tuberculosis. There was a 49-56% probability of DATs improving the cost-effectiveness of tuberculosis treatment and there was no significant difference in disability adjusted life years (DALYs) between study arms. The implementation of DATs did not change the distribution of costs or DALYs between people with tuberculosis (PWTB) of different household socio-economic position, however it did reduce the magnitude of patient costs among PWTB in the lower socio-economic position (SEP) quintile.

Implications of all the available evidence

While there is limited evidence of the effectiveness of Digital Adherence Technologies (DATs), this study is the first to show what impact the DATs may have on the costs of treatment, by reducing the number of healthcare visits leading to cost savings. There is further evidence that DATs may reduce the burden of patient costs on those who are least wealthy. We recommend that future investments in DATs for tuberculosis treatment support consider how healthcare providers integrate DATs for tuberculosis treatment support in the health facility workflow and how this translates to cost savings.