Effectiveness of acute medical units in hospitals: a systematic review

To assess the effectiveness of acute medical units (AMUs) in hospitals. (i) Controlled and observational studies in peer-reviewed journals retrieved from PubMed, EPOC, CINAHL and ERIC databases published between January 1990 and July 2008; and (ii) reports from non-peer-reviewed websites combined with Google search. Articles reporting effects of the introduction of an AMU on mortality, length of stay, discharge disposition, readmissions, resource use and patient and/or staff satisfaction. Data on unit operations and outcome measures were extracted by a single author and confirmed by a second author, with disagreement settled by consensus. Nine peer-reviewed reports of before-after analyses of seven units introduced into the UK and Ireland were analysed. Two studies, one prospective, reported significant reductions in in-patient mortality between 0.6 and 5.6% points following commencement of AMU. Four studies reported significant reductions in the length of stay between 1.5 and 2.5 days. Waiting times for patient transfer from emergency departments to medical beds decreased by 30% in one study. In three studies, the proportion of medical patients discharged directly home from the AMU increased by 8-25% points. Three studies noted no increase in 30-day readmission rates following unit commencement. Two studies described significant improvements in patient and staff satisfaction with care. Eight non-peer-reviewed reports relating to 48 units confirmed reductions in the length of stay. Limited observational data suggest AMUs reduce in-patient mortality, length of stay and emergency department access block without increasing readmission rates, and improve patient and staff satisfaction.