Pain persists in a moderate number of patients following hip or knee replacement surgery. Persistent pain may subsequently lead to the prolonged consumption of analgesics after surgery and expose patients to the adverse drug events of opioids and NSAIDs, especially in older patients and patients with comorbidities. This study aimed to identify risk factors for the increased use of opioids and other analgesics 1 year after surgery and focused on comorbidities and surgery-related factors.
All patients who underwent a primary hip or knee replacement for osteoarthritis from 2002 to 2013 were identified. Redeemed prescriptions for acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids (mild and strong) were collected from a nationwide Drug Prescription Register. The user rates of analgesics and the adjusted risks ratios for analgesic use 1 year after joint replacement were calculated.
Of the 6238 hip replacement and 7501 knee replacement recipients, 3591 (26.1%) were still using analgesics 1 year after surgery. Significant predictors of overall analgesic use (acetaminophen, NSAID, or opioid) were (risk ratio (95% CI)) age 65-74.9 years (reference < 65), 1.1 (1.03-1.2); age > 75 years, 1.2 (1.1-1.3); female gender, 1.2 (1.1-1.3); BMI 30-34.9 kg/m
Obesity (especially BMI > 35 kg/m