Concerns on methodological assumptions in the health economic evaluation of return-to-work interventions

The analysis is transparent and well executed, but the study's headline finding - lifetime dominance of I-MORE when productivity is counted - hinges on structural assumptions that effectively extend a 3½-week inpatient program into persistent productivity gains over a 25-year horizon: transition intensities are frozen beyond 4 years, and within-state absence-day differences are held constant thereafter, generating persistent productivity gains even after state prevalences converge. Health-related quality of life is observed only to 14 months and then modeled as state-specific constants, compressing incremental quality-adjusted life years and leaving the healthcare-only incremental cost-effectiveness ratio unfavorable. We argue that lifetime savings should be treated as upper-bound estimates and that decision relevance would be strengthened by waning-effect scenarios, mid-term horizons, and tests of the absorbing disability state. We also highlight the need for diagnosis-by-treatment analyses and stepped-care sequences given the heterogeneous population and fixed-dose ACT comparator.