The Norton scoring system was found to be a powerful predictor of both short- and long-term outcomes in patients with acute heart failure, according to a retrospective, single center study published in the Journal of Cardiology.
Patients (n=4388) with acute heart failure admitted to the Sheba Medical Center in Israel between 2008 and 2017 were recruited. Norton scores were evaluated by a nurse upon admission. The most frail patients had Norton scores ≤15, intermediate scores were between 16 and 18, and the most fit patients had scores ≥19. Short-term outcomes were defined as 30- and 90-days and long-term outcomes were defined as 1 year.
The study participants had evenly distributed Norton scores, with 32% classified as low, 28% as intermediate, and 40% as high scores. The patient characteristics were not consistent within Norton score categories. Patients in the low vs intermediate and high score groups were significantly older (P <.001), were predominantly women (P <.001), had higher ejection fraction (), and had greater prevalence of some comorbidities (eg, hypertension, atrial fibrillation, chronic renal failure, anemia; P <.001 for all) and lower prevalence of other comorbidities (eg, cardiomyopathy)
At 30-days, a significantly higher percentage of patients with low vs high Norton scores had died (16.1% vs 2.6%, respectively; P <.001). This trend was similar after 90 days (23.2% vs 5.2%, respectively; P <.001) and 1 year (23.2% vs 10.2%, respectively; P <.001).
Norton scores were found to be an independent predictor of mortality regardless of age, sex, or heart failure etiology. Patients in the low vs high scoring group had an increased risk for all-cause mortality at 30 days (hazard ratio [HR], 4.17; 95% CI, 3.16-5.05; P <.001) and at 1 year (HR, 3.11; 95% CI, 2.53-3.82; P <.001). Patients with intermediate vs high Norton scores had increased risk for mortality and hospitalization for heart failure at 30 days (HR, 2.01; 95% CI, 1.49-2.72; P <.001) and 1 year (HR, 1.99; 95% CI, 1.61-2.48; P <.001).
Combining Norton scores with standard prognostic factors (ie, age, gender, diabetes mellitus, anemia, chronic kidney disease, chronic obstructive pulmonary disease, and left ventricular ejection fraction) resulted in a 21.5% improvement in reclassification for predicting long-term mortality (95% CI, 18.3%-25.1%).
Study limitations include the fact that Norton scores are not specific to heart failure, but assesses patient frailty.
“The Norton admission score can be used to identify patients [with heart failure] prone to adverse outcomes. Frailty is a major predictor of short and long-term mortality and should be incorporated in the general assessment of patients [with heart failure],” concluded the study authors.
Natanzon S S, Maor E, Klempfner R, et al. Norton score and clinical outcomes following acute decompensated heart failure hospitalization. J Cardiol. 2020;S0914-5087(20)30178-7. doi:10.1016/j.jjcc.2020.05.016