Keele Research Repository

Objectives
To produce national and regional estimates and trends of gabapentinoid-opioid co-prescribing rates in patients with osteoarthritis, both in absolute terms and relative to matched controls without osteoarthritis.

Methods
Using the UK Clinical Practice Research Datalink database we first constructed age-sex-practice-date 1:1 matched cohorts of patients aged ≥40 years with and without a new diagnosis of osteoarthritis between 1995-2017 and estimated the relative incidence of first gabapentinoid prescription. Incident gabapentinoid users in both cohorts were followed to estimate and compare the event-rate of gabapentinoid-opioid co-prescription (prescription from both classes within the same 28-day window).

Results
The incidence of first gabapentinoid prescription was 3-fold higher in patients with osteoarthritis than in matched controls (n=215,357; incidence rate ratio (IRR) 2.93; 95%CI: 2.87-3.00). Among incident gabapentinoid users with osteoarthritis (n=27,374, median follow-up 3.9 years) the event-rate of gabapentinoid-opioid co-prescription was 4.03 (4.02-4.05) per person-year. The rate was higher in osteoarthritis patients classed as long-term gabapentinoid users (6.24; 6.22-6.26). These rates were significantly higher than incident gabapentinoid users without osteoarthritis (adjusted-IRR: 1.29 (1.28-1.30)). This elevated risk was observed across age, sex, geographic-regions, and calendar-years, when restricted to strong-opioids and to long-term gabapentinoid users, and when co-prescription was defined as within 14-days and same-day prescribing.

Conclusions
Patients with osteoarthritis not only have a higher risk of being prescribed a gabapentinoid but, once prescribed a gabapentinoid, are also at greater risk of opioid co-prescription. Strict restriction of gabapentinoid-opioid co-prescription, and improved access to, and uptake of, effective non-pharmacological and surgical alternatives for osteoarthritis are required.