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

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.