Increasing wait times predict increasing mortality for emergency medical admissions.

Background: The actual impact of emergency department (ED) 'wait' time on hospital mortality in patients admitted as a medical emergency has often been debated. We have evaluated the impact of such waits on 30-day mortality, for all medical patients over a 7-year period.

Methods: All patients admitted as medical emergencies by the ED between 2002 and 2008 were studied; we looked at the impact of time to medical referral and subsequent time to a ward bed on any inhospital death within 30 days. Significant univariate predictors of outcome, including Charlson's comorbidity and acute illness severity score, were entered into a multivariate regression model, adjusting the univariate estimates of the readmission status on mortality.

Results: We studied 23 114 consecutive acute medical admissions between 2002 and 2008. The triage category in the ED was highly predictive of subsequent 30-day mortality ranging from 4.8 (category 5) to 46.1% (category 1). After adjustment for all outcome predictors, including comorbidity and illness severity, both door-to-team and team-to-ward times were independent predictors of death within 30 days with respective odds ratios of 1.13 (95% confidence interval 1.07-1.18), and 1.07 (95% confidence interval 1.02-1.13).

Conclusion: Delay to admission have been shown to be independently adversely related to mortality outcome. We recommend maximal target limits of 4 and 6 h for referrals and admissions, respectively, based on these mortality observations.