Tag Archives: Hospital deaths

Declining Readmission Rates – Are They Associated with Increased Mortality?

I have always been a bit nihilistic about reducing readmission rates to hospitals.[1][2] However, I may have been overly pessimistic. A new study confirms that it is possible to reduce readmission rates by imposing financial incentives.[3] Importantly, this does not seem to have caused an increase in mortality – as might occur if hospitals were biased against re-admitting sick patients in order to avoid a financial penalty. “False null result” (type two error), do I hear you ask? Probably not, since the data are based on nearly seven million admissions. In fact, 30 day mortality rates were slightly lower among hospitals that reduced readmission rates.

— Richard Lilford, CLAHRC WM Director


  1. Lilford RJ. If Not Preventable Deaths, Then What About Preventable Admissions? NIHR CLAHRC West Midlands News Blog. 6 May 2016.
  2. Lilford RJ. Unintended Consequences of Pay-For-Performance Based on Readmissions. NIHR CLAHRC West Midlands News Blog. 13 January 2017.
  3. Joynt KE, & Maddox TM. Readmissions Have Declined, and Mortality Has Not Increased. The Importance of Evaluating Unintended Consequences. JAMA. 2017; 318(3): 243-4.

Yet Again, Low Proportion of Hospital Deaths Judged Preventable

Hogan and colleagues have reported another study on preventable mortality based on case-note review among 34 hospitals.[1] Only 3.6% of deaths were thought to have been preventable on the balance of probability. Preventability rates did not vary widely between hospitals.

Of course, this might be something of an underestimate because deaths where the probability of preventability was less than 50% are not included. The CLAHRC WM Director calculates preventability as the sum of all cases that may have been preventable, weighted by the probability that they were preventable. He also likes to adjust for the reviewer effect to minimise the influence of unusually ‘hawkish’ reviewers.

Despite these precautions, preventability is “in the eye of the reviewer,”[2] and may be over-estimated because of hindsight bias, or under-estimated because some practices that may increase the risk of death cannot be discerned from case-notes.

— Richard Lilford, CLAHRC WM Director


  1. Hogan H, Zipfel R, Neuburger J, Hutchings A, Darzi A, Black N. Avoidability of hospital deaths and association with hospital-wide mortality ratios: retrospective case record review and regression analysis. BMJ. 2015; 351: h3239.
  2. Hayward RA, Hofer TP. Estimating hospital deaths due to medical errors: preventability is in the eye of the reviewer. JAMA. 2001; 286(4): 415-20.

Measuring Quality of Care

McGlynn and Adams [1] repeat a point frequently made by the CLAHRC WM Director – before using outcomes to judge the quality of care, first model plausible effects.[2] [3] Only a small fraction of an outcome may be amenable to improved care.

The rate of hospital deaths in the UK is about 3%. Allowing a generous 20% of those to be preventable sets an upper headroom for improvement of 0.6%. So don’t expect quality of care to show up in mortality statistics. Or, to take another example, about 1% of hospital patients suffer a preventable medication related adverse event.[4] So don’t expect improved medicine management to show up in quality of life scores among the hospital population.

— Richard Lilford, CLAHRC WM Director


  1. McGlynn EA, Adams JL. What makes a good quality measure? JAMA. 2014; 312(15): 1517-8.
  2. Yao GL, Novielli N, Manaseki-Holland S,Chen YF, van der Klink M, Barach P, Chilton PJ, Lilford RJ. Evaluation of a predevelopment service delivery intervention: an application to improve clinical handovers. BMJ Qual Saf. 2012; 21(s1): i29-38.
  3. Girling AJ, Hofer TP, Wu J, Chilton PJ, Nicholl JP, Mohammed MA, Lilford RJ. Case-mix adjusted hospital mortality is a poor proxy for preventable mortality: a modelling study. BMJ Quality & Safety. 2012; 21: 1052-6.
  4. de Vries EN, Ramrattan MA, Smorenburg SM, Gouma DJ, Boermeester MA. The incidence and nature of in-hospital adverse events: a systematic review. Qual Saf Health Care. 2008; 17(3): 216-23.

Preventable hospital deaths and other measures of safety

Readers of this blog may well know the views of the CLAHRC WM Director on using hospital mortality to compare hospital safety.[1] [2] Following the recommendations in the Keogh review, published in 2013, there was greater interest in looking at preventable hospital deaths in order to improve the NHS.

Helen Hogan and colleagues have recently published findings of a retrospective case record review that looked for relationships between preventable hospital deaths and eight other measures of safety in ten English acute hospital trusts.[3] Of the eight measures of safety they looked at, only MRSA bacteraemia rate had a significant association with proportion of preventable deaths (P<0.02). Hospital Standardised Mortality Ratios (HSMRs), widely used in the UK to measure safety, was not significantly associated (P=0.97). Additionally, the difference in the proportion of preventable deaths between hospitals was not statistically significant (P=0.94), varying from 3–8%. The authors are planning a larger study in order to establish these findings, with 24 additional UK hospitals.

— Richard Lilford, Director CLAHRC WM


  1. Girling AJ, Hofer TP, Wu J, Chilton PJ, Nicholl JP, Mohammed MA, Lilford RJ. Case-mix adjusted hospital mortality is a poor proxy for preventable mortality: a modelling study. BMJ Qual Saf. 2012; 21(12): 1052-6.
  2. Lilford RJ, Pronovost P. Using hospital mortality rates to judge hospital performance: a bad idea that just won’t go away. BMJ. 2010; 340: c2016.
  3. Hogan H, Healey F, Neale G, Thomson R, Vincent C, Black N. Relationship between preventable hospital deaths and other measures of safety: an exploratory study. Int J Qual Health Care. 2014; 26(3): 298-307.