The dynamics of the emergency medical readmission - The underlying fundamentals

Hospital readmissions are a perennial problem. We reviewed readmissions to one institution (2002-2015) and investigated their dynamics.

96,474 emergency admissions (in 50,701 patients) to an Irish hospital over a 15-year period were studied, and patterns surrounding early (<28days) and late (any other) readmissions determined. Univariate and logistic or truncated Poisson regression methods were employed.

Early readmission rate averaged 9.6% (95% CI: 9.4, 9.8) with a low/high of 8.4% (95% CI: 7.8, 9.1) and 10.3% (95% CI: 9.6, 11.0) respectively with no overall time trend. Early readmissions represented 20.1% (95% CI: 19.8, 20.5) of emergency medical readmissions. Median time to first readmission was 55weeks (95% CI: 13, 159), time to second was 35weeks (95% CI: 9, 98); by the 7th/8th readmissions, intervals were 13weeks (95% CI: 4, 36) and 11weeks (95% CI: 4, 30). Readmissions were older 67.1years (95% CI: 48.3, 79.2) vs. single admissions 53.9years (34.3, 72.4) and stayed longer - 5.8days (2.7, 10.6) vs. 3.9days (1.5, 8.0). Readmissions had more Acute Illness Severity, Charlson Co-Morbidity and Chronic Disabling Disease. Between 2002 and 2015 the logistic adjusted model of 30-day in-hospital mortality reduced from 6.1% (95% CI: 5.7, 6.5) to 4.4% (95% CI: 4.1, 4.7) (RRR 30.4%).

Early hospital readmission rate did not change over 15years despite improvements in hospital mortality outcomes. Readmissions have a consistent pattern related to patient illness and social characteristics; the fundamentals are driven by disease progression over time.