Economic evaluation of a rehabilitation program integrating exercise, self-management, and active coping strategies for chronic knee pain

OBJECTIVE: To conduct an economic evaluation of the Enabling Self-Management and Coping with Arthritic Knee Pain through Exercise (ESCAPE-knee pain) program. METHODS: Alongside a clinical trial, we estimated the costs of usual primary care and participation in ESCAPE-knee pain delivered to individuals (Indiv-rehab) or groups of 8 participants (Grp-rehab). Information on resource use and informal care received was collected during face-to-face interviews. Cost-effectiveness and cost-utility were assessed from between-group differences in costs, function (primary clinical outcome), and quality-adjusted life years (QALYs). Cost-effectiveness acceptability curves were constructed to represent uncertainty around cost-effectiveness. RESULTS: Rehabilitation (regardless of whether Indiv-rehab or Grp-rehab) cost £224 (95% confidence interval [95% CI] £184, £262) more per person than usual primary care. The probability of rehabilitation being more cost-effective than usual primary care was 90% if decision makers were willing to pay £1,900 for improvements in functioning. Indiv-rehab cost £314/person and Grp-rehab £125/person. Indiv-rehab cost £189 (95% CI £168, £208) more per person than Grp-rehab. The probability of Indiv-rehab being more cost-effective than Grp-rehab increased as willingness to pay (WTP) increased, reaching 50% probability at WTP £5,500. The lack of differences in QALYs across the arms led to lower probabilities of cost-effectiveness based on this outcome. CONCLUSION: Provision of ESCAPE-knee pain had small cost implications, but it was more likely to be cost-effective in improving function than usual primary care. Group rehabilitation reduces costs without compromising clinical effectiveness, increasing probability of cost-effectiveness.