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

Abstract

BACKGROUND: The factors influencing hospital readmissions are debated. We assessed whether readmissions could be predicted using routinely collected hospital data. METHODS: All emergency admissions to a single institution over 12years (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. RESULTS: 66,933 admissions were recorded in 36,271 patients. The readmission rates at 1, 3, 6 and 9years were 29.5%, 38.9%, 42.9% and 44.1%. Early readmissions represented 14.1%. In the multivariable model, an admission in the previous 6months 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 4weeks. CONCLUSION: Readmissions increase as a function of time; illness severity, chronic disabling disease score and a recent admission are the strongest predictors of readmission.