Health outcomes and costs in patients with osteoarthritis and chronic pain treated with opioids in Spain: the OPIOIDS real-world study

Objective: The objective of this study was to analyze health outcomes, resource utilization, and costs in osteoarthritis patients with chronic nociceptive pain who began treatment with an opioid in real-world practice in Spain. Methods: We designed a non-interventional, retrospective, longitudinal study with 36 months of follow-up using electronic medical records (EMRs) from primary care centers, of patients aged 18+ years who began a new treatment with an opioid drug in usual practice for chronic pain due to osteoarthritis. Health/non-health resource utilization and costs, treatment adherence, pain change, cognitive functioning, and dependence for basic activities of daily living (BADL) were assessed. Results: A total of 38,539 EMRs [mean age (SD); 70.8 (14.3) years, 72.3% female; 53.3% hip/knee, 25.0% spine, and 21.7% other sites] were recruited. A total of 19.1% of patients remained on initial opioid at 36 months, without significant differences by osteoarthritis site (p = 0.125). Mean total adjusted cost was euro17,915, with 27.7% corresponding to healthcare resources and 72.3% to lost productivity. Hospital admissions for osteoarthritis-related surgical interventions accounted for 15.8% of total healthcare cost. A slight mean pain reduction was observed: -1.3 points, -16.9%,p < 0.001, with increases in cognitive deficit (+3.3%,p < 0.001) and moderate to total dependence for BADL (+15.6%,p < 0.001) in a median duration of opioid use of 203 days (IQR: 89-696). Conclusions: In real-world practice in Spain, opioid use in osteoarthritis was high, but with low adherence. There were meaningful increases in resource use and costs for the National Health System. Pain reduction was modest, whereas cognitive impairment and dependence for BADL increased significantly.