Inappropriate opioid dispensing in patients with knee and hip osteoarthritis: a population-based cohort study.

OBJECTIVE: To estimate inappropriate opioid dispensing in patients with knee or hip osteoarthritis (OA) defined as (1) dispensing of opioids within the first year of diagnosis or (2) long-term opioid use. DESIGN: Data from Skåne Healthcare Register was linked with the Swedish Prescribed Drug Register. Incidence proportion of dispensed opioids within first year of incident knee or hip OA diagnosis was determined in knee (n = 399,670) and hip (413,216) OA cohorts without a history of OA. The 1-year period prevalence of long-term opioid dispensing was determined in a prevalence cohort (n = 48,574 with knee and/or hip OA and n = 457,587 without OA). The proportion of OA patients with excess opioid dispensing attributable to OA was estimated using inverse probability weighted regression adjustment. RESULTS: In the incident cohorts, 5866 and 2359 developed knee and hip OA, respectively. Within the first year after OA diagnosis 14.7% patients with knee OA and 20.7% with hip OA had an opioid dispensed. The estimated inappropriate dispensing attributable to OA was 7.4% (95% CI 6.5-8.4) for knee OA and 12.8% (95% CI 11.1-14.4) for hip OA. Among persons with prevalent knee, hip or knee and hip OA inappropriate, long-term opioid use attributable to OA was 1.3%, 2.0% and 2.4% of, respectively. CONCLUSIONS: More than half the incident opioid dispensations to patients within their first year after knee or hip OA diagnosis are inappropriate according to current treatment guidelines. Furthermore, 2% of patients with prevalent knee or hip OA have inappropriate long-term dispensing of opioids.