Abstract Body: Background: Outcomes and susceptibility to out-of-hospital cardiac arrest (OHCA) are known to differ by sex, yet little is known about changes in sex hormones after OHCA. We sought to determine the trajectory of sex hormones after OHCA and their association to survival and neurological outcome.

Methods: Plasma samples were collected from those that survived to hospital admission at four time points (1, 6, 24, and 48 hours) and estrone, estradiol, progesterone, and testosterone concentrations were quantified via liquid chromatography-mass spectrometry. Trends in hormones were plotted over time by sex and outcomes. The association between sex and hormone levels with survival and neurological outcome (cerebral performance category 1-2 indicating good outcome and 3-5 for poor outcome) were determined using Generalized Estimating Equation models.

Results: Of the 94 patients, 50 were males and 44 females. The mean age was 61.3 (+15.7) years and was comparable in males and females (p=0.38). Testosterone was the only hormone that resulted in significant differences in concentration between males and females. Over the 48 hours, estrone increased, testosterone decreased, and estradiol and progesterone remained flat. Survivors had lower levels of all hormones at all time points. Lower estrone level predicted survival at discharge, even after adjusting for sex and age (β=-3.38, 95% CI= -5.72, -0.85). Females had better neurological recovery compared to males after adjusting for estrone (β=1.27, 95% CI= 0.01, 2.53) and estradiol (β=2.92, 95% CI= 1.13, 4.70).

Conclusions: Survivors and those with favorable neurological outcome had lower trends in estrone, estradiol, progesterone and testosterone. In adjusted analysis, females had a better neurological recovery compared to males.