Abstract
Objectives: To determine the relationship between opioid use before joint replacement surgery and long-term postoperative outcomes.
Methods: This was a trial emulation study using linked administrative data. Participants included all patients who underwent joint replacement surgery for osteoarthritis in the New Zealand public healthcare system between July 2011 and June 2017. We assigned patients to treatment groups based on their opioid prescribing over the 3 months before surgery: none (control group), and equal quartiles of the observed distribution of the total morphine equivalent opioid dose. Inverse probability of treatment weighting was used to achieve between-group balance in baseline confounders. Outcomes measured over 6-year follow-up from the date of surgery included public healthcare utilisation and costs, employment and income, and adverse events including mortality, opioid overdose, and revision surgery.
Results: We included 26,064 patients. Participants with preoperative opioid prescribing had more hospitalisations, ED visits, pharmaceutical prescriptions, and opioid prescriptions, and higher total opioid dose and public healthcare costs, over 6-year follow-up than those in the no-opioid control group. There was little evidence of a dose-response relationship in these effects, with the exception of pharmaceutical—and particularly opioid—prescriptions. Those in the highest opioid dose group had lower income and employment rates, while no effect on these outcomes was seen in the lower opioid use groups. Most adverse events were more common in the treatment groups than in the control group, but these differences were generally not statistically significant.
Conclusions: Opioid use before joint replacement surgery is associated with worse outcomes over 6-year postoperative follow-up. Most of these negative impacts were seen at both low and high levels of preoperative opioid use, suggesting that low-dose opioid prescribing is unlikely to significantly mitigate the harms of preoperative opioid use. Efforts should be made to develop appropriate alternatives to opioid analgesics for people awaiting joint replacement surgery.