Does pain medication use influence the outcome of 8 weeks of education and exercise therapy in patients with knee or hip osteoarthritis?

Objective Patients with osteoarthritis are mainly managed in primary care settings and many patients use pain medication as symptomatic treatment. We investigated in OA-patients receiving an education and exercise program, the use and type of pain medication and its impact on outcomes at 3 months follow-up. Design, Setting and Subjects The design was a retrospective cohort study using prospectively collected data from the GLA: D® registry. The study included 15,918 primary care patients. Results Among the included patients, 62% were pain medication users and 38% were non-users. Among the pain medications users, 35% were classified as paracetamol users, 54% as NSAID users, and 11% as opioid users. Medication users and non-users differed regarding a higher pain intensity, poorer physical and mental health. Pain medication use before and during the education and exercise program was associated with the pain intensity at 3 months follow-up. However, patients either using or not using pain medications improved over time, and the magnitude of the difference between patient groups was small (less than 10 mm on a 0–100 scale). Conclusions Pain medication use is weakly associated with outcome at 3 months follow up in OA-patients receiving an education and exercise program. Between-group differences, however, are small and probably not clinically important.