No difference in mortality between men and women after out-of-hospital cardiac arrest

AIM: Comparing the outcome after out-of-hospital cardiac arrest (OHCA) in men and women and to determine whether sex modifies the effect of targeted temperature management (TTM) at 33 or 36°C.

METHODS: The TTM trial randomized 950 patients to TTM at 33 or 36°C for 24h. This predefined sub-study of the TTM trial assessed survival and neurological outcome defined as Cerebral Performance Category (CPC) and modified Rankin Scale (mRS) using female sex as main predictor of outcome, in relation to level of TTM and other confounding factors.

RESULTS: Compared to men, women more often had OHCA at home, p=0.04 and less often had bystander defibrillation, p=0.01. No other differences in arrest circumstances were found. Coronary angiography (CAG) and percutaneous coronary intervention (PCI) <24h after ROSC was less often performed in women, both: p=0.02. Female sex was associated with higher mortality in univariate analysis, hazard ratio (HR)=1.29, CI=1.04-1.61, p=0.02 compared to men. Adjusting for demographic factors (age and comorbidity), arrest circumstances, pre-hospital findings, inclusion sites, treatments and status at admission reduced this: HR=1.11, CI=0. 87-1.41, p=0.42, and sex was no longer an independent risk factor for death. The effect of sex did not modify the effect of TTM at 33 and 36°C, pinteraction=0.73.

CONCLUSION: Female sex seems associated with adverse outcome, but this association is largely explained by differences in arrest circumstances and in-hospital treatment. Our data shows no interaction between sex and the effect of targeting 33 vs. 36°C.