B-po03-166 nighttime sudden death in women

We recently reported that women are at increased risk for sudden cardiac arrest (SCA) at night. Especially since women tend to be older, social settings could contribute to these differences but have not been evaluated. We performed a sex-specific analysis of the circumstances and outcomes of SCA resuscitation at night to evaluate the potential role of differences in social settings. We studied adult out-of-hospital SCA cases from an ongoing prospective population-based study in the US Northwest (catchment population approx. 1 million, 2002-2016). SCA was defined as sudden collapse with loss of pulse likely due to a cardiac etiology that occurred during nighttime hours (9PM - 6AM). We performed a comprehensive analysis of circumstances, emergency medical response data and clinical records. Survivors of SCA and deceased patients were included. Of 4126 total SCA cases, 1076 occurred during nighttime hours, and 405 (37.7%) of these were women. Women with SCA at night were older than men (65.8±18.3 vs 63.6±17.5, p<0.001), were less likely to be witnessed (47.9% vs 54.2%, p=0.02), were more likely to be in a care facility (p<0.001), and were more likely to have Do Not Resuscitate (DNR) orders (13.1% vs 8.7%, p=0.04). Bystander CPR, response times, and survival to hospital discharge were not significantly different between men and women with SCA at night. Women with SCA at night are older, are more likely to have a DNR order, and have less witnessed cardiac arrest, possibly due to higher rates of living alone. In addition to sex-specific pathophysiology, social determinants of higher nighttime rates of SCA in women warrant further investigation.