A multidisciplinary lifestyle programme for patients with rheumatoid arthritis and metabolic syndrome-associated osteoarthritis: economic evaluation alongside the ‘Plants for Joints’ randomized controlled trials

Abstract

Objective: To evaluate the cost-effectiveness of the ‘Plants for Joints’ intervention for rheumatoid arthritis (RA) and metabolic syndrome-associated osteoarthritis (MSOA) patients over 16 weeks. Method: Data from two randomized controlled trials were analysed. The first included 77 RA patients (intervention = 40; control = 37) and the second 64 MSOA patients (intervention = 32; control = 32). The intervention comprised a 16 week lifestyle programme including a whole-food plant-based diet, exercise, and stress management; control participants received usual care. Data from both trials were analysed together and separately. Costs were measured from societal and healthcare perspectives. Effects were expressed in quality-adjusted life-years (QALYs). Results: The intervention cost €886/patient. Intervention group participants gained more QALYs than the control group (0.009; 95% confidence interval −0.004 to 0.023), equivalent to 3.3 additional days in ‘perfect health’ (0.009 × 365). Healthcare costs were higher in the intervention group, while societal costs were lower. None of these differences was statistically significant. From a societal perspective, the intervention had a moderate to high probability of being cost-effective compared with usual care, while the probability was low from a healthcare perspective. Stratified analyses indicated that the probability of cost-effectiveness was higher in RA than in MSOA patients. This difference became less pronounced after excluding outliers. Conclusion: The Plants for Joints intervention demonstrated a relatively high probability of cost-effectiveness from a societal perspective, although this was lower from a healthcare perspective. If these benefits are sustained in the long term, this intervention may reduce the disease and economic burden of arthritic conditions.