Ranking Hospitals on Preventable Deaths – an Article that Everyone Should Read

The UK government plans to rank hospitals on avoidable mortality based on case reviews of 2,000 deaths in English hospitals each year. They plan to use the method developed by Hogan et al.,[1] which designates a death as preventable when the reviewer concludes that the probability that the death could have been prevented exceeds 50% (P>0.5).

A recent article [2] criticises the use of a single threshold of preventability (e.g. P< or >=0.5) to determine whether or not a death was preventable. CLAHRC WM, in collaboration with Tim Hofer of University of Michigan, has advocated the use of a six-point Likert or a sliding scale to overcome the loss of information from dichotomising preventability.[3]

While preventable mortality rates provide real information on hospital performance, reviewer reliability is rather low (i.e. inter-observer variability is high).[3] This means that the signal can easily be obscured by noise.[4] Further modelling work may shed light on the extent to which this reduces the accuracy of league table approaches to identify outliers.Meanwhile, it is clear that while measuring preventable deaths overcomes some of the problems associated with measuring all deaths,[5] it nevertheless is no panacea. Measurement of preventability should probably be used as a learning tool, rather than as a performance metric.

— Richard Lilford, CLAHRC WM Director


  1. Hogan H, Healey F, Neale G, et al. Preventable deaths due to problems in care in English acute hospitals: a retrospective case record review study. BMJ Qual Saf. 2012; 21(9): 737-45.
  2. Abel G, Lyratzopoulos G. Ranking hospitals on avoidable death rates derived from retrospective case record review: methodological observations and limitations. BMJ Qual Saf. 2015; 24: 554-7.
  3. Manaseki-Holland S, Lilford RJ, Bishop J, et al. Reviewing deaths in British and US hospitals: a study of case-note reviews. 2015. [Submitted].
  4. Girling AJ, Hofer TP, Wu J, et al. Case-mix adjusted hospital mortality is a poor proxy for preventable mortality: a modelling study. BMJ Qual Saf. 2012; 21(12): 1052-6.
  5. Lilford R & Pronovost P. Using hospital mortality rates to judge hospital performance: a bad idea that just won’t go away. BMJ. 2010; 340: c2016.

One thought on “Ranking Hospitals on Preventable Deaths – an Article that Everyone Should Read”

  1. I was moved by the final sentence of this article to leave a reply. In an era where National Government, DoH and the NHS advocate transparency and patient safety, I would agree with this statement. One must always consider the effect when a new outcome measure is introduced. However good the intentions might be to measure measurable deaths, is it really going to change practice? Or will something else change? Having a learning tool built within the process acts as a feedback, which closes the loop and will inevitably increase patient safety.

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