Long-term outcome of an AMAU-a decade's experience

Background: There is interest in emergency medical admissions, the outcomes of major reconfigurations and the development of systems and processes for Acute Medicine. We report on the long-term outcomes of an Acute Medical Admissions Unit, using a database of emergency admissions to St James' Hospital, Dublin, from 2002 to 2012. Methods: All emergency admissions (67 971 episodes in 37 828 patients) were tracked and in-hospital mortality, length of stay and emergency 'wait' numbers and times summarized. We examined outcomes using generalized estimating equations, an extension of generalized linear models that permitted adjustment for correlated observations (readmissions). Margins statistics used adjusted predictions to test for interactions of key predictors while controlling for other variables using computations of the average marginal effect. Results: By episode, the in-hospital mortality averaged 5.8% (95% CI 5.6-5.9%); the relative risk reduction (RRR) was 35.0% between 2002 and 2012, from 7.0% to 4.6% (P = 0.001), with a number needed to treat (NNT) of 40.7. By unique patient the in-hospital mortality averaged 10.3% (95% CI 10.0-10.6%) with a RRR of 60.0% from 14.5% to 5.7% (P = 0.001), with an NNT of 11.4. Emergency Department 'wait' numbers decreased by 43%. The main mortality outcome predictors were Illness Severity, Charlson Comorbidity, Manchester Triage Category, O-2 saturation, blood culture results, transfusion requirement and a primary respiratory or neurological diagnosis; the model had a high AUROC of 0.88 (95% CI 0.87, 0.88). Conclusion: Institution reform can result in substantial outcome and process measure benefits, improving care delivery to emergency medical admissions.