Risk Factors for Chronic Opioid Use Following Hip and Knee Arthroplasty: Evidence from New Zealand Population Data.

Background: Patients awaiting total joint arthroplasty (TJA) have high rates of opioid use, and many continue to use opioid medications long term after surgery. The objective of this study is to estimate the risk factors associated with chronic opioid use after TJA in a comprehensive population-based cohort.

Methods: All patients undergoing TJA in the New Zealand public healthcare system were identified from Ministry of Health records. Dispensing of opioid medications up to 3 years postsurgery and potential risk factors, including demographic, socioeconomic, and surgery-related characteristics, pre-existing medical comorbidities, and use of other analgesic medications prior to surgery, were identified from linked population databases. Logistic regression analysis was used to identify factors associated with chronic postoperative opioid use.

Results: The strongest risk factor for chronic postoperative opioid use was preoperative opioid use. Other significant risk factors included perioperative opioid use, history of alcohol or drug abuse, younger age, female gender, knee arthroplasty, several comorbid health conditions, and preoperative use of some analgesic medications. Protective factors included higher education levels and preoperative use of nonsteroidal anti-inflammatory drugs. Most risk factors had similar effects on chronic postoperative opioid use irrespective of the length of follow-up considered (1, 2, or 3 years).

Conclusion: This study of a comprehensive nationwide population-based cohort of TJA patients with 3 years of follow-up identified several modifiable risk factors and other easily measured patient characteristics associated with higher risk of long-term postoperative opioid use.