Using the Get With The Guidelines-Stroke risk model as a risk assessment tool can help physicians better predict in-hospital mortality risk after stroke, according to the results of a study published in the Sept. 27 issue of Circulation.
The study’s principal investigator Eric E. Smith, MD, from the University of Calgary in Alberta, Canada, and colleagues assessed data from more than 274,988 hospital stroke admissions from the American Heart Association and American Stroke Association’s Get with the Guidelines stroke registry, which reported stroke admissions between 2001 and 2007.
The authors split patients into a derivation (60 percent) and validation sample (40 percent).
Researchers stratified patients by those who died and those who survived stroke and analyzed characteristics of each of the groups and identified certain characteristics that predicted in-hospital death post-stroke. The authors validated a model of 109,197 patients who had National Institutes of Health Stroke Scale (NIHSS) scores recorded.
"We used these results to make a risk score," Smith said. "One of our findings was that a measure of stroke severity, called the National Institutes of Health Stroke Scale, was a very strong predictor of mortality risk.
The results showed that 5.5 percent of the total patients admitted for stroke experienced in-hospital death. The rate of in-hospital death was 5.2 percent for patients who had a recoded NIHSS score. Using a risk score not included in the NIHSS, researchers found that the risk of death for the lowest risk category was 0.7 percent. In contrast, the results showed that the risk of death was 16.2 percent for the highest category of risk.
When utilizing the NIHSS, the risk of death was 0.4 percent in the lowest category compared to 26.8 percent in the highest risk category.
Additionally the researchers found that patients who were older, who arrived by ambulance and who were diagnosed with atrial fibrillation had a higher risk of dying compared to other patients. The authors noted that previous stroke history, carotid stenosis, high blood pressure, high cholesterol and smoking were not huge in the forecasting of mortality risk.
"We showed that the risk score that included the NIHSS score made more accurate predictions," Smith said. "Clearly, stroke severity is the most important predictor of outcome — even more important than the person's age and medical history."
The researchers said that one limitation of the study stemmed from the fact that they only evaluated patients with ischemic stroke and do not fully yet understand whether the predictions are valid for other stroke type patients.
"Future research will be needed to examine how the risk score is used and its effect on clinical practice, to determine the characteristics associated with differences in observed versus expected mortality at the patient and hospital level, and to determine whether an accurate risk score can be developed for hemorrhagic stroke types," the authors concluded.