Performance of clinical risk scores to predict mortality and neurological outcome in cardiac arrest patients

Aim: Several scores are available to predict mortality and neurological outcome in cardiac arrest patients admitted to the intensive care unit (ICU). The aim of the study was to externally validate the prognostic value of four previously published risk scores.

Methods: For this observational, single-center study, we prospectively included 349 consecutive adult cardiac arrest patients upon ICU admission. We calculated two cardiac arrest specific risk scores (OHCA and CAHP) and two general severity of illness scores (APACHE II and SAPS II). The primary endpoint was in-hospital mortality. Secondary endpoints were neurological outcome at hospital discharge and 30-day mortality.

Results: 170 patients (49%) died until hospital discharge. All scores were independently associated with outcomes in logistic regression analysis and showed acceptable discrimination for in-hospital mortality with highest AUCs of the cardiac arrest specific risk scores (OHCA: 0.80 (95%CI 0.75-0.85) and CAHP: 0.84 (95%CI 0.79-0.88) compared to the severity of illness scores (APACHE II: 0.78 (95%CI 0.73-0.83) and SAPS II: 0.77 (95%CI 0.72-0.82). Results were robust in subgroup analysis except for worse performance in elderly patients (>75 years) and patients with respiratory cause of cardiac arrest. Results were similar for 30-days mortality and slightly higher for neurological outcome.

Conclusions: This study confirms the good prognostic performance of cardiac arrest specific scores to predict mortality and neurological outcomes in cardiac arrest patients. Routine use of OHCA or CAHP score helps to objectively risk stratify these vulnerable patients and thereby may improve therapeutic decisions.