The Importance of Treatment Adherence and Long-Term Outcomes in Health Economic Impact Evaluations

Wydick et al. recently estimated the impact of Ponseti clubfoot treatment on human flourishing in Ethiopia, providing important evidence for scaling clubfoot programs in low- and middle-income countries. However, their definition of "treated" warrants scrutiny. Considering children in the final stages of casting as treated, only captures outcomes during the early stage of a 4-year treatment course, implicitly assuming full bracing adherence and no relapse. This is inconsistent with relapse rates of 30%-40% and two-year discontinuation rates exceeding 50% in comparable settings. This choice of definition likely underestimates late-initiated treatment impact and overestimates early-initiated treatment impact. Modeling the clubfoot care pathway as a probabilistic value model incorporating dropout, non-adherence, and relapse, I re-estimate population-level functional outcomes at mid-childhood. In settings without additional surgical care availability the mean level of functionality is estimated at 55.2% of normal function (95% CI 54.6%-55.9%), showing that enrollment expansion alone cannot achieve impact at the scale implied. Achieving clubfoot treatment's full potential at scale requires comprehensive, longitudinal care beyond initial Ponseti treatment, and stronger collaboration between clinical and health-economics communities to ground future estimates in clinical reality.