International validation of the out-of-hospital cardiac arrest score in the United States.
OBJECTIVE
Investigators in France have developed a risk score to predict death or poor neurologic outcome after out-of-hospital cardiac arrest. The aim of this study is to externally validate this score in an independent patient population in the United States.


DESIGN
Retrospective, observational, cohort study.


PATIENTS
Patients being admitted to the intensive care unit after out-of-hospital cardiac arrest.


SETTING
Two geographically distinct tertiary care hospitals in the United States.


INTERVENTIONS
None.


MEASUREMENTS AND MAIN RESULTS
The primary end point was poor outcome, defined as either death or a Cerebral Performance Category score of 3-5. The secondary end point was all-cause mortality. Calibration was assessed by comparing the number of expected outcomes based on the logistic model of the French study with observed outcomes within this study using Hosmer-Lemeshow C test (goodness-of-fit). Discrimination was assessed by calculation of the area under the receiver operating characteristic curve. Of a total of 128 patients, 99 (77%) had a poor outcome, including 91 nonsurvivors (71%). The probability of poor neurologic outcome and mortality increased stepwise with increasing out-of-hospital cardiac arrest score. Graphic display of observed against predicted outcomes and goodness-of-fit test indicated good calibration of the score (p = .4). The score showed good discrimination for poor outcome (area under the receiving operating characteristic curve, 0.85; 95% confidence interval, 0.79-0.92) and for mortality (area under the receiving operating characteristic curve, 0.85; 95% confidence interval, 0.78-0.91). In patients with an out-of-hospital cardiac arrest score >40 points and >60 points, the positive predictive value for poor outcome was 97% and 100%, respectively.


CONCLUSIONS
This study found good calibration and high discrimination of the out-of-hospital cardiac arrest score in two geographically distinct patient populations in the United States. Particularly, this score had a high positive predictive value and performed well in identifying high-risk patients for poor outcomes.