Are vital sign abnormalities associated with poor outcomes after emergency department discharge?

To examine association between vital sign abnormalities in the emergency department (ED) and early death after ED discharge, we performed a matched case-control study. Conditional logistic regression showed that presence of any vital sign abnormality at ED discharge was significantly associated with over three-fold increase in likelihood of death within 15 days of ED discharge (OR: 3.06, 95%CI: 2.81-4.48). Even small changes were associated with increased risk: every additional beat increase in heart rate conferred additional risk (OR: 1.04, 95%CI: 1.02-1.06), while every additional oxygen saturation percentage point was protective (0.89, 0.80-0.98). However, none of these vital sign abnormalities was a good predictor of early death; there was poor discrimination and substantial overlap in values between cases and controls.