OBJECTIVES: Opioid prescribing has markedly increased in UK and worldwide, predominantly for chronic non-cancer pain (CNCP). CNCP includes conditions such as fibromyalgia, low back pain and osteoarthritis (OA). Evidence suggests that widespread use of opioids in CNCP is associated with risks of diversion and abuse, overdose and death. However, opioid prescribing data in specific medical conditions are limited and no study has examined the trends of prescribing in patients with OA in UK. OA affects around 7 million people in the UK with knee joint being most commonly affected. This study aims to describe opioid prescribing trends in patients with knee osteoarthritis (KOA) managed in primary care in UK.

METHODS: This retrospective cross-sectional study over a period from 2000-2015 used data from the Clinical Practice Research Datalink (CPRD). Opioid prescriptions for patients (≥ 18years) with a clinician-recorded diagnosis of KOA were retrieved. Outcome measures included: number of patients & prescriptions, defined daily doses (DDD), oral morphine equivalent dose (OMEQ) and days’ supply. Descriptive statistics were used to report outcomes in each year.

RESULTS: Overall, 137,107 patients with KOA were included (58.3% female, mean age: 65.1±12.9 years). In total 4,276,368 prescriptions for opioid were prescribed for 115,057 patients (84% of total diagnosed with KOA). The mean number of prescriptions increased from 5 to 8 prescriptions/patient/year while, the mean annual DDD/1000 registrants increased from 0.16 ± 0.01 to 0.21 ± 0.1 (31 % increase) in 2000 and 2015 respectively. The mean OMEQ increased from 12.7 mg/day in 2000 to 15.5 mg/day in 2015 (22% increase) and the mean (±SD) annual days of supply was 86.7 ±107.3 days.

CONCLUSIONS: The prevalence of opioid prescribing in KOA increased between 2000 and 2015. Doses prescribed have also increased modestly. As the prevalence of KOA increases, further research into the risks and benefits of opioids in KOA is required.