Objectives To evaluate the cost effectiveness, cost utility and cost benefit of a workplace intervention compared with usual care for sick-listed employees with distress.

Methods An economic evaluation was conducted alongside a randomised controlled trial. Employees with distress and who were sick-listed for 2–8 weeks were randomised to a workplace intervention (n=73) or to usual care (n=72). The workplace intervention is a stepwise process involving the sick-listed employee and their supervisor, aimed at formulating a consensus-based plan for return to work (RTW). The effect outcomes were lasting RTW and quality-adjusted life years (QALYs). Healthcare utilisation was measured over 12 months. Cost effectiveness analyses (CEA) and cost utility analyses (CUA) were conducted from the societal perspective and cost benefit analyses (CBA) from the employer perspective. Bootstrapping techniques were used to estimate cost and effect differences, related CIs, and cost effectiveness and cost utility ratios. Cost effectiveness planes were presented and subgroup analyses were performed.

Results CEA and CUA revealed no statistically significant differences in lasting RTW, QALYs or costs. The CBA indicated a statistically significant higher cost of occupational health services in the workplace intervention group. The workplace intervention was not cost effective according to the CEA, CUA and CBA.

Conclusions Widespread implementation of the workplace intervention for sick-listed employees with distress is not recommended because there was no economic benefit compared with usual care. Future trials should confirm if the workplace intervention is cost effective for the subgroup employees who intended to return to work despite symptoms.

This trial has been registered at the Dutch National Trial Register ISRCTN92307123.