A Pilot Study Examining the Severity and Outcome of the Post–Cardiac Arrest Syndrome

Abstract

Background— Cardiac arrest occurs in >400 000 patients in the United States per year, and mortality rates vary across the country. Whether variations in cardiac arrest outcome are the result of differences in hospital or patient characteristics remains understudied. We tested whether hospital-independent factors would account for the difference in outcome between 2 geographically distinct hospitals. Methods and Results— Consecutive adult (age >18 years) out-of-hospital cardiac arrests were considered for analysis. The primary outcome was in-hospital mortality. Predictor variables were classified according to whether they were hospital-independent or whether they could be related to the hospital's quality of care. Only hospital-independent variables were considered for the analysis. Sequential logistic modeling was used to assess outcome. A propensity score was derived and was used in subsequent multivariate logistic regression to predict hospital outcome. A total of 208 subjects were included. Overall mortality in the Detroit cohort was 87% in comparison with 61% in the Boston cohort (odds ratio: 4.4; 95% confidence interval: 2.2–8.8). After sequential adjustments for baseline covariates, out-of-hospital cardiac arrest score and propensity score, city was not significantly associated with mortality (odds ratio: 1.16; 95% confidence interval: 0.45–2.97). After propensity matching there was no significant difference in the odds ratio for death between the 2 cities (odds ratio: 1.15; 95% confidence interval: 0.51–2.61). Conclusions— In this pilot study, we found that pre- and intra-arrest conditions contribute substantially to the severity of the postarrest syndrome and on outcomes. Postarrest quality-of-care evaluations should include inherent differences in the presenting syndrome rather than a crude mortality rate.