The first time inclusion of cardiac arrest in the latest version of the ACTION Registry-Get With the Guidelines (GWTG) in-hospital mortality risk model following myocardial infarction, increases the efficacy of this tool for assessing death risk among hospitalized patients, researchers reported.

The updated model replaces an earlier version of the in-hospital mortality risk prediction tool, and it was based on data from MI patients hospitalized over a 2-year period from 2012 through 2013.

In an analysis, researcher Robert L. McNamara, MD, of Yale University School of Medicine, New Haven, Connecticut, and colleagues, wrote that the revised model should "enable improved assessment of hospital quality and enhance research into best practices to further reduce morality in patients with acute MI." The new model and analysis were published online August 1 in the Journal of the American College of Cardiology.

"The addition of risk adjustment for patients presenting after cardiac arrest is critically important and enables a fairer assessment across hospitals with varied case mix," they wrote.

In addition to cardiac arrest, other independent predictors of outcome included in the risk assessment model are patient age, presenting systolic blood pressure, heart rate at presentation, cardiogenic shock or heart failure at presentation, type of heart attack, creatinine clearance, and troponin ratio.

The analysis of data on 243,440 MI patients treated at 655 hospitals across the nation between January of 2012 and December of 2013 revealed an in-hospital mortality rate of 4.6%.



Risk scores varied significantly based on patient characteristics and clinical presentation. Younger heart patients without many other risk factors who did not present with cardiac arrest had a less than 1% risk of dying while hospitalized, while the death risk was close to 50% among older patients presenting with cardiac arrest and other risk factors.

"Observed mortality rates varied substantially across risk groups, ranging from 0.4% in the lowest group (score <30) to 49.5% in the highest group (score >59%)," the researchers wrote.

The revised model was found to perform well in subgroups based on age, sex, race, and transfer status; as well as the presence of diabetes, renal dysfunction, cardiac arrest, cardiogenic shock, and ST-segment elevation MI.

The researchers wrote that the revised model "represents a robust, parsimonious approach to contemporary risk adjustment methodology for in-hospital mortality after acute MI." But they also cited several potential limitations, including the voluntary nature of the registry.

"The contributing hospitals tend to be larger referral centers and are more likely to have PCI capabilities than the average U.S. hospital," they wrote, adding that in-hospital outcomes may not be generalizable to smaller hospitals. They noted that the inclusion of additional information on patient baseline health status, such as frailty or other noncardiac conditions, could increase the robustness of the model.

In an editorial published with the study, Peter Wilson, MD, of Emory University School of Medicine in Atlanta, Georgia and Ralph D'Agostino Sr., PhD, of Boston University, wrote that research is needed comparing the growing number of risk algorithms for in-hospital MI outcomes, which now include TIMI, GRACE, ACTION-GWTG, HEART, and DAPT.

"Until now, clinicians and researchers have generally used either the TIMI or GRACE score to guide therapeutic decisions," they wrote. "With the advent of the ACTION score, which appears to be more helpful for patients with moderate-to-severe disease, and the HEART score, which targets care for patients with minimal-to-mild disease, there are other options." They noted that a comprehensive, cross validation and comparison of TIMI, GRACE, HEART, DAPT, AND ACTION could provide valuable information.

"It is likely that one score does not fit all," they wrote. "Each algorithm provides a useful summary of risk to help guide decision-making for patients with ischemic symptoms depending on the severity of the signs and symptoms at presentation and the duration of the follow-up interval. Consensus building would help to move this field forward for hospital-based management of patients evaluated for cardiac ischemia."