Emergency readmissions are substantially determined by acute illness severity and chronic debilitating illness: A single centre cohort study

•Readmissions are common in acute general medical patients.•Factors including illness severity, chronic disability, and health service pressures influence readmissions.•Acute illness severity is the strongest predictor of an early readmission.

BackgroundThe factors influencing hospital readmissions are debated. We assessed whether readmissions could be predicted using routinely collected hospital data.MethodsAll emergency admissions to a single institution over 12 years (2002–2013) were included. The predictor variables, of acute illness severity, Manchester Triage Category, chronic disabling disease and Charlson co-morbidity scores, were studied univariably and entered into a multivariable logistic regression model to predict the bivariate of any readmission or none. A zero truncated Poisson regression model assessed the predictors against the readmission count and incidence rate ratios were calculated. Factors reflecting the clinical load on the emergency department were examined.Results66,933 admissions were recorded in 36,271 patients. The readmission rates at 1, 3, 6 and 9 years were 29.5%, 38.9%, 42.9% and 44.1%. Early readmissions represented 14.1%. In the multivariable model, an admission in the previous 6 months was the strongest predictor of readmission, OR of 5.02 (95% CI: 4.86, 5.18). Acute illness severity — OR of 2.68 (95% CI: 2.33, 3.09) for group VI vs group I, and chronic disabling score — OR of 2.08 (95% CI: 1.87, 2.32) for a score of 4 + vs 0 were significant predictors of readmission in the multivariable model. Both of these predictors demonstrated a linear relationship. Illness severity was the strongest predictor of an early readmission within 4 weeks.ConclusionReadmissions increase as a function of time; illness severity, chronic disabling disease score and a recent admission are the strongest predictors of readmission.