Simultaneous prognostic score validation in patients with out-of-hospital cardiac arrest by a post-hoc analysis based on national multicenter registry

Abstract

Using a nationwide multicenter prospective registry in Japan's data, we calculated prognostic and predictive scores, including the Out-of-Hospital Cardiac Arrest (OHCA); Cardiac Arrest Hospital Prognosis (CAHP); Nonshockable rhythm, Unwitnessed arrest, Long no-flow or Long low-flow period, blood PH < 7.2, Lactate > 7.0 mmol/L, End-stage chronic kidney disease on dialysis, Age ≥ 85 years, Still resuscitation, and Extracardiac cause (NULL-PLEASE); revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST); and MIRACLE2 scores, for adult patients with cardiac arrest. The MIRACLE2 score was validated with the modified MIRACLE2 score, which excludes information of pupillary reflexes. Each score was calculated only for the cases with no missing data for the variables used. These scores' accuracies were compared using neurological outcomes 30 days after out-of-hospital cardiac arrest (OOHCA). Patients with a cerebral performance category scale of 1 or 2 were designated as having favorable neurological outcomes. Each score's discrimination ability was evaluated by the receiver operating characteristic curve's area under the curve (AUC). To assess in detail in areas of high specificity and high sensitivity, which are areas of interest to clinicians, partial AUCs were also used. The analysis included 11,924 hospitalized adult patients. The AUCs of the OHCA, MIRACLE2, CAHP, rCAST, and NULL-PLEASE scores for favorable neurological outcomes were 0.713, 0.727, 0.785, 0.761, and 0.831, respectively. The CAHP and NULL-PLEASE scores were significantly more accurate than the rest. Accuracies did not differ significantly between the CAHP and NULL-PLEASE scores. The NULL-PLEASE score was significantly better at discriminating favorable neurological prognoses at 30 days in patients with OOHCA compared to other scoring systems.

Figure 1

Flow chart of the study population. The patient groups surrounded by thick lines are those included in the present analysis. CPC: cerebral performance category scale, ECG: electrocardiogram, EMS: emergency medical services, ER: emergency room, OOHCA: out-of-hospital cardiac arrest, ROSC: return of spontaneous circulation.

Figure 2

Distributions of patients for each score and the predicted and actual rates of favorable neurological outcomes in each category. Right vertical axis, number of patients; left vertical axis, percentage; horizontal axis, classification of each score. The NULL-PLEASE and mMIRACLE2 scores are the measured values; while the OHCA, rCAST, and CAHP scores are shown in tenths of the range of scores obtained in this validation. NULL-PLEASE: Nonshockable rhythm, Unwitnessed arrest, Long no-flow or Long low-flow period, blood PH < 7.2, Lactate > 7.0 mmol/L, End-stage chronic kidney disease on dialysis, Age ≥ 85 years, Still resuscitation, and Extracardiac cause; OHCA: Out-of-Hospital Cardiac Arrest; rCAST: revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia; CAHP: Cardiac Arrest Hospital Prognosis.

Figure 3

Comparison of receiver operating characteristic (ROC) curves for each score. ^aP value < 0.05 compared with OHCA score. ^bP value < 0.05 compared with mMIRACLE2 score. ^cP value < 0.05 compared with rCAST score. AUC: area under the curve, ROC: receiver operating characteristic, CI: confidence interval, NULL-PLEASE: Nonshockable rhythm, Unwitnessed arrest, Long no-flow or Long low-flow period, blood PH < 7.2, Lactate > 7.0 mmol/L, End-stage chronic kidney disease on dialysis, Age ≥ 85 years, Still resuscitation, and Extracardiac cause; OHCA: Out-of-Hospital Cardiac Arrest; rCAST: revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia; CAHP: Cardiac Arrest Hospital Prognosis.