The effectiveness and variation of acute medical units: a systematic review.
OBJECTIVE
To evaluate the evidence for the effectiveness of acute medical units (AMUs) compared with other models of care and compare the components of AMU models.


METHODS
Six electronic databases and grey literature sources searched between 1990 and 2014.


METHODS
Studies reporting on AMUs as an intervention for unplanned medical presentations to hospital with the inclusion of all outcome measures/study designs/comparators.


METHODS
Data on study characteristics/outcomes/AMU components were extracted by one author and confirmed by a second.


RESULTS
Seventeen studies of 12 AMUs across five countries were included. The AMU model was associated with a reduction in-hospital length of stay (LOS) in all analyses ranging from 0.3 to 2.6 days; and a reduction in mortality in 12 of the 14 analyses with the change ranging from a 0.1% increase to a 8.8% reduction. Evidence relating to readmissions and patient/staff satisfaction was less conclusive. There was variation in the following components of AMUs: admission criteria, entry sources, functions and consultant work patterns.


CONCLUSIONS
This review provides evidence that AMUs are associated with reductions in-hospital LOS and, less convincingly, mortality compared with other models of care when implemented in European and Australasian settings. Reported estimates may be affected by residual confounding. This review reports heterogeneity in components of the AMU model. Further work to identify what constitutes the key components of an AMU is needed to improve the quality and effectiveness of acute medical care. This is of particular importance given the escalating demand on acute services.
The Royal College of Physicians of Edinburgh, Quality, Research and Standards Office, 9 Queen Street, EH2 1JQ Edinburgh, UK Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK.
Lindsay E M
LE
Reid
Imperial College London, SW7 2AZ, UK.
Lotte C
LC
Dinesen
The Royal College of Physicians of Edinburgh, Quality, Research and Standards Office, 9 Queen Street, EH2 1JQ Edinburgh, UK.
Michael C
MC
Jones
Business School, University of Aberdeen, UK.
Zoe J
ZJ
Morrison
Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK Edinburgh Clinical Trials Unit, Edinburgh, UK.
Christopher J
CJ
Weir
Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK.
Nazir I
NI
Lone
D017598:Efficiency, Organizational; D004632:Emergency Medical Services / Q000592:standards*; D006801:Humans; D038622:Internationality
acute medical unit; systematic review; variation