Sex Differences in Opioid Administration After Cardiac Surgery

Abstract

Objectives: To assess whether there are sex-based differences in the administration of opioid analgesic drugs among inpatients after cardiac surgery.

Design: A retrospective cohort study.

Setting: At a tertiary academic referral center.

Participants: Adult patients who underwent cardiac surgery from 2014 to 2019.

Interventions: None.

Measurements and main results: The primary outcome was the cumulative oral morphine equivalent dose (OMED) for the postoperative admission. Secondary outcomes were the daily difference in OMED and the administration of nonopioid analgesics. The authors developed multivariate regression models controlling for known confounders, including weight and length of stay. A total of 3,822 patients (1,032 women and 2,790 men) were included. The mean cumulative OMED was 139 mg for women and 180 mg for men, and this difference remained significant after adjustment for confounders (adjusted mean difference [aMD], -33.21 mg; 95% CI, -47.05 to -19.36 mg; p < 0.001). The cumulative OMED was significantly lower in female patients on postoperative days 1 to 5, with the greatest disparity observed on day 5 (aMD, -89.83 mg; 95% CI, -155.9 to -23.80 mg; p = 0.009). By contrast, women were more likely to receive a gabapentinoid (odds ratio, 1.91; 95% CI, 1.42-2.58; p < 0.001). The authors found no association between patient sex and the administration of other nonopioid analgesics or specific types of opioid analgesics. The authors found no association between patient sex and pain scores recorded within the first 48 hours after extubation, or the number of opioids administered in close proximity to pain assessments.

Conclusions: Female sex was associated with significantly lower amounts of opioids administered after cardiac surgery.

Keywords: cardiac surgery; non-opioid analgesia; opioid analgesia; postoperative pain; sex differences.