Effectiveness of acute medical units in hospitals: a systematic review

Int J Qual Health Care. 2009 Dec;21(6):397-407. doi: 10.1093/intqhc/mzp045.


Purpose: To assess the effectiveness of acute medical units (AMUs) in hospitals.

Data sources: (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.

Study selection: 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 extraction Data on unit operations and outcome measures were extracted by a single author and confirmed by a second author, with disagreement settled by consensus.

Results of data synthesis: 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.

Conclusion: 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.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Efficiency, Organizational*
  • Hospital Mortality
  • Hospital Units / organization & administration*
  • Hospital Units / statistics & numerical data*
  • Humans
  • Length of Stay / statistics & numerical data
  • Patient Care Team / organization & administration
  • Patient Readmission / statistics & numerical data
  • Patient Satisfaction