Mud-Bath Therapy in Addition to Usual Care in Bilateral Knee Osteoarthritis: An Economic Evaluation Alongside a Randomized Controlled Trial

Objective: To perform a cost-effectiveness analysis of mud-bath therapy (MBT) in addition to usual treatment compared to usual treatment alone in patients with bilateral knee osteoarthritis (OA). Methods: An economic evaluation alongside a randomized controlled trial was conducted. Patients were randomly assigned to receive either a 2-week cycle of MBT in addition to their usual treatment or to continue routine care alone. The EuroQol 5-domain questionnaire was administered at baseline, 2 weeks, and at 3, 6, 9, and 12 months. Direct health care resource consumption data up until 12 months were derived from a daily diary given to patients and returned at prescheduled followup visits. Results: A total of 103 patients were included (n = 53 for MBT patients; n = 50 for controls). Overall, patients in the MBT group accrued mean ± SD 0.835 ± 0.10 quality-adjusted life years (QALYs) compared to 0.753 ± 0.11 in the control group (P < 0.001). Average direct costs per patient (€303 versus €975; P < 0.001) were higher in the control group, primarily because of hospitalization for total knee replacement and use of intraarticular hyaluronic acid. Bootstrapping replications of costs and QALY sample distributions consistently indicated that the MBT therapy combined with standard therapy represents a dominant strategy as compared with standard therapy alone. The probability of MBT being cost-effective at standard cost-effectiveness thresholds (e.g., €20,000/QALY) is 100%. Conclusion: The results of this cost-effectiveness analysis support the use of MBT as midterm complementary therapy in the management of knee OA.