Can biochemical analyses risk stratify acutely admitted medical patients: an external validation of two existing systems

Methods The study was completed as a prospective observational cohort study at a regional teaching hospital. The discriminatory power (ability to discriminate between survivors and non-survivors) of the models was estimated using the area under the receiver-operating characteristics curve (AUROC). Values above 0.8 represent good discriminatory power. Calibration (accuracy of the prediction) was assessed using Hosmer-Lemeshow c goodness of fit test with a p-value above 0.05 indicating acceptable calibration. The blood tests used for calculation were drawn upon admission, and always within 2 hours of arrival at the department. As this was an observational study, only analyses ordered by the treating physician were included.