Cost‐Effectiveness of Diet and Exercise for Overweight and Obese Patients With Knee Osteoarthritis

Objective The Intensive Diet and Exercise for Arthritis ( IDEA ) trial showed that an intensive diet and exercise (D+E) program led to a mean 10.6‐kg weight reduction and 51% pain reduction in patients with knee osteoarthritis ( OA ). The aim of the current study was to investigate the cost‐effectiveness of adding this D+E program to treatment in overweight and obese (body mass index >27 kg/m 2 ) patients with knee OA . Methods We used the Osteoarthritis Policy Model to estimate quality‐adjusted life‐years ( QALY s) and lifetime costs for overweight and obese patients with knee OA , with and without the D+E program. We evaluated cost‐effectiveness with the incremental cost‐effectiveness ratio ( ICER ), a ratio of the differences in lifetime cost and QALY s between treatment strategies. We considered 3 cost‐effectiveness thresholds: $50,000/ QALY , $100,000/ QALY , and $200,000/ QALY . Analyses were conducted from health care sector and societal perspectives and used a lifetime horizon. Costs and QALY s were discounted at 3% per year. D+E characteristics were derived from the IDEA trial. Deterministic and probabilistic sensitivity analyses ( PSA s) were used to evaluate parameter uncertainty and the effect of extending the duration of the D+E program. Results In the base case, D+E led to 0.054 QALY s gained per person and cost $1,845 from the health care sector perspective and $1,624 from the societal perspective. This resulted in ICER s of $34,100/ QALY and $30,000/ QALY . In the health care sector perspective PSA , D+E had 58% and 100% likelihoods of being cost‐effective with thresholds of $50,000/ QALY and $100,000/ QALY , respectively. Conclusion Adding D+E to usual care for overweight and obese patients with knee OA is cost‐effective and should be implemented in clinical practice.