A cost-utility analysis for return-to-work interventions comparing alternative methods for handling missing health-related quality of life data.

Most quality-of-life data were missing: only 42 participants had complete data at all follow-ups, and complete-case analysis excluded 117. The analysis is an economic evaluation, not a direct test of whether either programme improved health. The cost-effectiveness conclusion depended on perspective: healthcare costs alone and societal costs including lost productivity gave opposite results. The analysis assumed data were missing at random. If missingness depended on unobserved factors, the methods used here are not valid without adjustment. The sample was too small to test hybrid missing-data methods. A 14-month scenario was an exception to the base-case robustness. I-MORE combined inpatient care, ACT, and return-to-work-focused elements, while O-ACT was group-based ACT, so the analysis cannot separate the contribution of any single component.

The authors declared no conflicts of interest. The Hysnes project was funded by the Liaison Committee between the Central Norway Regional Health Authority and the Norwegian University of Science and Technology, the Research Council of Norway, and allocated government funding through the Central Norway Regional Health Authority. The funders had no role in design, data collection, analysis, interpretation, writing, or publication decisions.

Do not conclude that I-MORE is cost-effective in all settings. It was cost-effective only when lost productivity costs were included. With healthcare costs alone it was not, and the quality-of-life estimates relied on imputing missing data for most participants.