Effect of intra-articular corticosteroid injections for osteoarthritis on the subsequent use of pain medications: a UK CPRD cohort study

Objectives
To estimate the effect of intra-articular corticosteroid injection (IACI) for osteoarthritis on longer-term incidence of pain medications.

Methods
We conducted a cohort study of patients registered in the UK Clinical Practice Research Datalink (CPRD) GOLD primary care database with an incident diagnosis of knee, hip, hand or shoulder osteoarthritis between 2005 and 2019. Exposure of interest was single or repeated use of IACI (analysed separately). Main outcome measures were five-year incidence of uncombined opioids, opioid-nonopioid analgesic combinations, oral corticosteroids, paracetamol, oral non-steroidal anti-inflammatory drugs (NSAIDs) and topical NSAIDs. Instrumental variable (IV) analysis was used, given this methodology can account for strong and unmeasured confounding. Secondary analyses used propensity-score matching and Cox regression.

Results
Amongst 74 527 knee osteoarthritis patients, IACI use was associated with lower subsequent prescribing of most pain medications studied, including opioid-nonopioid analgesic combinations following single IACI [number needed to treat (NNT) = 5 (95% CI: 5–6), P < 0.001] and uncombined opioids following repeat IACI [NNT = 12 (8–546), P = 0.049]. Amongst 15 092 hand osteoarthritis patients, single IACI was associated with reduced use of opioid-nonopioid combinations, paracetamol and oral NSAIDs. Secondary analyses confirmed lower incidence rates of opioid-nonopioid combinations after single IACI for knee [hazard ratio (HR) = 0.88 (0.81–0.96)], hip [HR = 0.76 (0.62–0.92)], hand [HR = 0.77 (0.61–0.98)] or shoulder [HR = 0.72 (0.53–0.99)] osteoarthritis.

Conclusions
IACI for knee or hand osteoarthritis showed lower incidence of several pain medications over the longer-term relative to no IACI use. Secondary findings suggest IACI may be effective in reducing longer-term use of opioid-nonopioid analgesic combinations for patients with knee, hip, hand or shoulder osteoarthritis.