A clinical and biochemical score for mortality prediction in patients with acute dyspnoea: derivation, validation and incorporation into a bedside programme.

Abstract

Risk stratification for patients with acute dyspnoea is a challenging task. No quantitative tool for mortality prediction among patients with acute dyspnoea is available. 595 dyspnoeic subjects were enrolled in an emergency department. Clinical and biochemical factors independently predictive of death by 1 year were used to develop a mortality risk prediction tool. Seven factors comprised the final tool: age (x0.3), heart rate (x0.2), blood urea nitrogen (x0.3), New York Heart Association class (x5), amino-terminal pro-B-type natriuretic peptide (NT-proBNP) >or=986 pg/ml (18 points), systolic blood pressure <100 mm Hg (11 points) and presence of a murmur (11 points). A continuous rise in mortality was seen from 1.7% in the lowest score quintile (n = 118; score <or=48.5) to 43.1% in the highest quintile (n = 116, score >or=85.5; p<0.001 for trend). Receiver operating characteristic curve analysis of the score's accuracy produced an area under the curve (AUC) of 0.82 (95% CI 0.78 to 0.85) with similar AUCs in subjects with acutely destabilised heart failure (AUC = 0.73, 95% CI 0.67 to 0.79) and those without (AUC = 0.83, 95% CI 0.77 to 0.85, p for the comparison = NS). The score was validated in a separate population of dyspnoeic patients (AUC = 0.73, 95% CI 0.64 to 0.82; p<0.001) and was incorporated into a computer program suitable for near-patient calculation. A new risk stratification tool for acutely dyspnoeic patients has been derived and validated.