Prediction of heart failure mortality in emergent care: a cohort study
Lee DS, Stitt A, Austin PC, Stukel TA, Schull MJ, Chong A, Newton GE, Lee JS, Tu JV. Ann Intern Med. 2012; 56(11):767-75. Epub Jun 5 2012.
Background — Heart failure contributes to millions of emergency department (ED) visits, but hospitalization-versus-discharge decisions are often not accompanied by prognostic risk quantification.
Objective — To derive and validate a model for acute heart failure mortality applicable in the ED.
Design — Clinical data abstraction with development of a broadly applicable multivariate risk index for 7-day death using initial vital signs, clinical and presentation features, and readily available laboratory tests.
Setting — Multicenter study of 86 hospitals in Ontario, Canada.
Patients — Population-based random sample of 12,591 patients presenting to the ED from 2004 to 2007.
Measurements — Death within 7 days of presentation.
Results — In the derivation cohort (n = 7433; mean age, 75.4 years [SD, 11.4]; 51.5% men), mortality risk increased with higher triage heart rate (adjusted odds ratio [OR], 1.15 [95% CI, 1.03 to 1.30] per 10 beats/min) and creatinine concentration (OR, 1.35 [CI, 1.14 to 1.60] per 1 mg/dL [88.4 μmol/L]), lower triage systolic blood pressure (OR, 1.52 [CI, 1.31 to 1.77] per 20 mm Hg) and initial oxygen saturation (OR, 1.16 [CI, 1.01 to 1.33] per 5%). Non-normal serum troponin levels (OR, 2.75 [CI, 1.86 to 4.07]) were associated with increased mortality risk. Areas under the receiver-operating characteristic curves of the multivariate model were 0.805 for the derivation data set (bootstrap-corrected, 0.811) and 0.826 for validation data set (n = 5158; mean age, 75.7 years [SD, 11.4]; 51.6% men). In the derivation cohort, a multivariate index score stratified 7-day mortality with rates of 0.3%, 0.3%, 0.7%, and 1.9% in quintiles 1 to 4, respectively. Mortality rates in the 2 highest risk groups were 3.5% and 8.2% in deciles 9 and 10, respectively.
Limitation — Left ventricular ejection fraction was not included in the model.
Conclusion — A multivariate index composed of routinely collected variables stratified mortality risk with high discrimination in a broad group of patients with acute heart failure presenting to the ED.
Emergency medical services