(P-520) Off-label Day-of-surgery Gabapentinoids and Prolonged Opioid Use: A Retrospective Cohort Study of Medicare Patients Using Electronic Health Records

Background: Gabapentinoids are increasingly incorporated into multimodal analgesia protocols for surgery. However, these drugs are not approved by the US FDA for use in managing surgical pain, and little is known regarding the effects of this off-label use on prolonged post-surgical opioid use following surgery.

Objectives: We estimate the association between preoperative day-of-surgery gabapentinoid administration on the risk of prolonged postsurgical opioid use.

Methods: We identified older adults (65+ years) undergoing surgery using electronic health records (EHR) from a large integrated healthcare system in the southeast (2016-2019). Exposure to preoperative gabapentinoids was measured using inpatient medication administration records on the day of surgery, and the outcome of prolonged opioid use was measured using outpatient medication orders. We used stabilized inverse probability of treatment weights with 1% asymmetric trimming to adjust for patient demographics, baseline health indicators, preoperative pain score, and surgical details. We used log-binomial regression to estimate risk ratios and 95% confidence intervals (CI) of prolonged opioid use comparing patients who received preoperative gabapentinoids to those who did not.

Results: Overall, 17,435 surgical patients met inclusion criteria, of whom 17.2% received preoperative gabapentinoids. The overall observed 90-day risk of prolonged opioid use following surgery was 1.20% (95% CI: 1.05, 1.38) patients. The adjusted risk ratio of prolonged opioid use comparing patients who received a dose of preoperative gabapentinoids on the day of surgery to those who did not was 1.67 (95% CI: 0.85,3.23).

Conclusions: Using data from a large integrated health system, we did not find evidence that preoperative gabapentinoids reduced the risk of prolonged opioid use in patients undergoing a broad range of surgeries. Off-label use of these medications to manage surgical pain should be carefully evaluated.