Sex-based disparities in bystander CPR for out-of-hospital cardiac arrest related to non-prescription drug use

Background: Non-prescription drug toxicity accounts for up to 10% of out-of-hospital cardiac arrests (OHCAs). Bystander cardiopulmonary resuscitation (CPR) improves OHCA outcomes but may be influenced by the patient's sex and the bystander's perceptions of non-prescription drug use. We examined differences in bystander CPR for OHCA of female and male cases with evidence of recent non-prescription drug use. Methods: We used the BC Cardiac Arrest Registry to identify emergency medical system-treated non-traumatic adult OHCAs (2019-2024) with evidence of recent non-prescription drug use. We assessed the association between patient sex and the primary outcome of bystander CPR, and secondary outcomes of bystander naloxone administration, automated external defibrillator (AED) application, and CPR technique, using multivariable logistic regression. Results: Among 3012 included cases, the median age was 40 years (Quartile 1 = 31, Quartile 3 = 50) and 826 (27%) were female. Female sex (compared to male) was associated with a higher odds of receiving bystander CPR (adjusted odds ratio [aOR] 1.2; 95% CI: 1.0-1.5). Female sex was not associated with bystander naloxone administration (aOR 1.0; 95% CI: 0.81-1.3) or AED application (aOR 0.82; 95% CI: 0.48-1.4). Female sex was associated with a higher odds of receiving compression-plus-ventilation CPR versus compression-only CPR (aOR 1.8; 95% CI: 1.0-3.0), although CPR type was frequently not noted. Conclusion: In OHCA cases with evidence of recent non-prescription drug use, female sex was associated with a higher odds of receiving bystander CPR and compression-plus-ventilation CPR. We did not detect an association between sex and bystander naloxone or AED application.