Sex-related differences in opioid administration in the emergency department: a population-based study.

Background Sex differences in pain experience and expression may influence ED pain management. Our objective was to evaluate the effect of sex on ED opioid administration. Methods We conducted a multicentre population-based observational cohort study using administrative data from Calgary’s four EDs between 2017 and 2018. Eligible patients had a presenting complaint belonging to one of nine pain categories or an arrival pain score >3. We performed multivariable analyses to identify predictors of opioid administration and stratified analyses by age, pain severity and pain category. Results We studied 119 510 patients (mean age 47.4 years; 55.4% female). Opioid administration rates were similar for men and women. After adjusting for age, hospital site, pain category, ED length of stay and pain severity, male sex was not a predictor of opioid treatment (adjusted OR (aOR)=0.93; 95% CI 0.85 to 1.02). However, men were more likely to receive opioids in the categories of trauma (aOR=1.58, 95% CI 1.40 to 1.78), flank pain (aOR=1.24, 95% CI 1.11 to 1.38), headache (aOR=1.18, 95% CI 1.03 to 1.34) and abdominal pain (aOR=1.11, 95% CI 1.08 to 1.18). Pain category appears to be a strong determinant of opioid administration, especially back pain (aOR=6.56, 95% CI 5.99 to 7.19) and flank pain (aOR=6.04, 95% CI 5.48 to 6.65). There was significant variability in opioid provision by ED site (aOR 0.76 to 1.24). Conclusions This population-based study demonstrated high variability in opioid use across different settings. Overall, men and women had similar likelihood of receiving opioids; however men with trauma, flank pain, headache and abdominal pain were much more likely to receive opioids. ED physicians should self-examine their analgesic practices with respect to possible sex biases, and departments should introduce evidence-based, indication-specific analgesic protocols to reduce practice variability and optimise opioid analgesia.