Journal of General Internal Medicine

, Volume 32, Issue 6, pp 686–696 | Cite as

The Association Between Hospital Capacity Strain and Inpatient Outcomes in Highly Developed Countries: A Systematic Review

  • Carl O. Eriksson
  • Ryan C. Stoner
  • Karen B. Eden
  • Craig D. Newgard
  • Jeanne-Marie Guise
Review Paper



Increases in patient needs can strain hospital resources, which may worsen care quality and outcomes. This systematic literature review sought to understand whether hospital capacity strain is associated with worse health outcomes for hospitalized patients and to evaluate benefits and harms of health system interventions to improve care quality during times of hospital capacity strain.


Parallel searches were conducted in MEDLINE, CINAHL, the Cochrane Library, and reference lists from 1999-2015. Two reviewers assessed study eligibility. We included English-language studies describing the association between capacity strain (high census, acuity, turnover, or an indirect measure of strain such as delayed admission) and health outcomes or intermediate outcomes for children and adults hospitalized in highly developed countries. We also included studies of health system interventions to improve care during times of capacity strain. Two reviewers extracted data and assessed risk of bias using the Newcastle-Ottawa Score for observational studies and the Cochrane Collaboration Risk of Bias Assessment Tool for experimental studies.


Of 5,702 potentially relevant studies, we included 44 observational and 8 experimental studies. There was marked heterogeneity in the metrics used to define capacity strain, hospital settings, and overall study quality. Mortality increased during times of capacity strain in 18 of 30 studies and in 9 of 12 studies in intensive care unit settings. No experimental studies were randomized, and none demonstrated an improvement in health outcomes after implementing the intervention. The pediatric literature is very limited; only six observational studies included children. There was insufficient study homogeneity to perform meta-analyses.


In highly developed countries, hospital capacity strain is associated with increased mortality and worsened health outcomes. Evidence-based solutions to improve outcomes during times of capacity strain are needed.


Hospital medicine Patient safety Systematic reviews Quality assessment Variations 



We are indebted to reference librarians Andrew Hamilton, MS, and Robyn Painter, MA-LIS, for their assistance creating search strategies, and to Marian McDonough, PharmD, Benjamin Sun, MD, MPP, and K. John McConnell, PhD, for general guidance.

Compliance with Ethical Standards

Conflict of Interest

Carl Eriksson and Craig Newgard received funding from the US Agency for Healthcare Research and Quality (AHRQ) during the conduct of the study. All other authors declare no conflicts of interest.

Funding Source

US Agency for Healthcare Research and Quality, 1 K12 HS022981 01. The funding agency played no role in the design or conduct of this research.

Supplementary material

11606_2016_3936_MOESM1_ESM.docx (80 kb)
ESM 1(DOCX 80 kb)


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Copyright information

© Society of General Internal Medicine 2016

Authors and Affiliations

  • Carl O. Eriksson
    • 1
  • Ryan C. Stoner
    • 2
  • Karen B. Eden
    • 2
  • Craig D. Newgard
    • 3
  • Jeanne-Marie Guise
    • 2
    • 3
    • 4
    • 5
  1. 1.Division of Pediatric Critical Care, Department of PediatricsOregon Health and Science UniversityPortlandUSA
  2. 2.Department of Medical Informatics and Clinical EpidemiologyOregon Health and Science UniversityPortlandUSA
  3. 3.Department of Emergency MedicineOregon Health and Science UniversityPortlandUSA
  4. 4.Department of Obstetrics and GynecologyOregon Health and Science UniversityPortlandUSA
  5. 5.OHSU-Portland State University School of Public HealthPortlandUSA

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