Lowering Hospital Bed Occupancy Associated With Reduced Patient Mortality

MedicalResearch.com Interview with:
Dr Daniel Boden

Emergency Medicine Consultant
Derby Hospitals NHS Foundation Trust

Medical Research: What is the background for this study? What are the main findings?

Dr. Boden: The overall objective was to evaluate whether there is an association between an intervention to reduce medical bed occupancy and both performance on the 4-hour target and hospital mortality.

We undertook a before-and-after study in Derby teaching Hospitals NHS Foundation Trust (a large UK District General Hospital) over a 32 month period. A range of interventions were undertaken to reduce medical bed occupancy within the Trust. Performance on the four-hour target and hospital mortality (HSMR, SHMI and Crude Mortality) were compared before, and after, intervention. Daily data on medical bed occupancy and percentage of patients meeting the four-hour target was collected from hospital records. Segmented regression analysis of interrupted time-series method was used to estimate the changes in levels and trends in average medical bed occupancy, monthly performance on the target and monthly mortality measures (HSMR, SHMI and crude mortality) that followed the intervention.

Medical Research: What are the main findings?

Dr. Boden:

  • Mean medical bed occupancy decreased significantly from 93.7% to 90.2% (p=0.02).
  • The trend change in 95% target performance, when comparing pre- and post-intervention, revealed a significant improvement (p=0.019).
    The intervention was associated with a mean reduction in all markers of mortality (range 4.5% – 4.8%). SHMI (p=0.02) and Crude Mortality (p=0.018) showed significant trend changes after intervention.
  • Our conclusion is that lowering medical bed occupancy is associated with reduced patient mortality and improved ability of the acute Trust to achieve the 95% four hour target. Whole system transformation is required to create lower average medical bed occupancy.

Medical Research: What should clinicians and patients take away from your report?

Dr. Boden: There are a number of things we feel should be taken away from this study:

  • There is growing evidence of the harm caused by “crowding” in the Emergency Department and “Exit Block” This study reveals one potential solution to this problem. If medical bed occupancy is reduced then patient “flow” is facilitated in their in-patient journey. This, in conjunction with improved ward-based care, results in less harm to patients (reduced mortality) as well as improvement in performance against the 95% 4 hour target.
  • Whole system transformation is required to facilitate this.
  • Association does not imply causation. It is important to be aware of potential confounding factors.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Boden: I will be seeking further advice on this. A multicentre study (ideally a cluster RCT) would be a big challenge. A more realistic alternative may involve an opportunistic observational study making use of changes in bed occupancy occurring at a number of hospitals that could be compared to controls that make no such intervention.


Lowering levels of bed occupancy is associated with decreased inhospital mortality and improved performance on the 4-hour target in a UK District General Hospital

D G Boden, A Agarwal, T Hussain, S J Martin, N Radford, M S Riyat, K So, Y Su, A Turvey,C I Whale

Emerg Med J emermed-2014-204479Published Online First: 17 September 2015doi:10.1136/emermed-2014-204479[email protected]

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Dr Daniel Boden (2015). Lowering Hospital Bed Occupancy Associated With Reduced Patient Mortality 

Last Updated on September 18, 2015 by Marie Benz MD FAAD