E. Harker1, C. A. Keilin1, R. Ahmed1, C. Katzman1, D. C. Cron1, T. Yao3, H. Hu1, J. S. Lee1, C. M. Brummett2, M. J. Englesbe1, J. F. Waljee1 1University Of Michigan,Department Of Surgery,Ann Arbor, MI, USA 2University Of Michigan,Department Of Anesthesiology,Ann Arbor, MI, USA 3University Of Michigan,School Of Public Health,Ann Arbor, MI, USA
Introduction: A significant number of surgical patients intermittently take opioids prior to elective surgery. Understanding the clinical trajectory of this large number of patients is critical to optimizing their care. We hypothesize that a longer duration of preoperative opioid use will be correlated with a longer duration of postoperative use.
Methods: We used a national employer-based insurance claims dataset to identify adults age 18 to 64 who were preoperatively either opioid-naïve or intermittent opioid users and who underwent a general, gynecologic, or urologic surgical procedure between January 2010 and March 2014 (N= 309,096). We defined preoperative intermittent opioid users as patients who filled ≤120 days’ supply of opioids between 365 and 31 days before surgery. Our primary explanatory variable was preoperative opioid exposure, measured as the number of months during which an opioid prescription was filled in the year prior to surgery (opioid-naïve, 1 month, 2-3 months, 4-6 months, 7-9 months, >9 months). Our outcome was time until last postoperative opioid script (considered the date of opioid discontinuation). We used survival analysis techniques, including Kaplan-Meier curves to compute estimated proportion of patients continuing to fill opioids postoperatively.
Results: In this cohort, 27% of patients used opioids intermittently in the year before surgery, and the majority of these patients (62%) filled opioids during 1 month preoperatively. Patients with a longer duration of preoperative opioid exposure continued to fill opioids for longer durations postoperatively (Figure). Most patients discontinued opioids after the initial prescription, but the remaining patients continued filling opioids long after surgery. Compared to patients with 1 month of opioid fills preoperatively, patients with >9 months of preoperative opioid fills had a 4-fold longer adjusted mean time until opioid discontinuation (326 vs. 84 days, P<0.001). The estimated proportion of patients continuing to fill ≥1 opioid script beyond 180 days was 90% among patients with >9 months of preoperative opioid use, 23% among patients with 1 month of preoperative use, and 15% among opioid-naïve.
Conclusion: Patients who intermittently use opioids prior to surgery are particularly vulnerable to prolonged postoperative opioid use. The surgical event should be considered an opportunity to wean opioid users postoperatively. Such strategies may have significant positive impact on the overall health and wellness of these surgical patients.
