Objective: To evaluate the impact of an acute assessment unit (AAU) on length of hospital stay (LOS), emergency department (ED) waiting times, direct discharge rate, unplanned readmission rate and all‐cause hospital mortality of general medical patients. Design and setting: Retrospective comparison of data for general medical patients admitted to a tertiary teaching hospital in Adelaide, South Australia, before and after the establishment of an AAU (reference years, 2003 [before] and 2006 [after]). Main outcome measures: Mean LOS, ED waiting times and all‐cause hospital mortality during calendar years 2003 (pre‐establishment) and 2006 (post‐establishment). Results: Following the establishment of an AAU, the mean LOS shortened (from 6.8 days in 2003 to 5.7 days in 2006; P < 0.001) despite a 50.5% increase in the number of admissions (from 2652 to 3992). The number of admitted patients waiting in the ED more than 8 hours for a hospital bed decreased (from 28.7% to 17.9%; P < 0.001), as did the number waiting more than 12 hours (from 20.2% to 10.4%; P < 0.001). The rates of unplanned readmission within 7 and 28 days did not change. The all‐cause hospital mortality for general medical admissions was 4.6% in 2003 v 3.7% in 2006 (P = 0.056). Conclusion: The establishment of an AAU within the general medical service coincided with decreases in both LOS and ED waiting times, despite a 50% increase in admissions. This structural reform in the process of acute medical care may have contributed to the improvement in these key health care performance indices without compromising the quality of patient care.

Many general medical inpatients (30%) have reduced kidney function at the time of admission. This study provides validation of the Modification of Diet in Renal Disease equation as a predictor of poor outcomes. Reduced renal function was associated with increased hospital LOS and mortality. Mortality rose with AKI and was explicable on the basis of the patients' age and co-morbidities. Renal insufficiency is documented infrequently in discharge summaries.