Intended for healthcare professionals

Rapid response to:


Medical error—the third leading cause of death in the US

BMJ 2016; 353 doi: (Published 03 May 2016) Cite this as: BMJ 2016;353:i2139

Rapid Response:

Unrealistic extrapolations discredit an important message

Most patients who die in hospital have had good care, but some have not. Most patients who have had poor quality care do not die, although some do. So, while it is superficially attractive for patient safety advocates to use numbers of “preventable deaths” to gain public attention, it is a self-defeating strategy if they produce a number which lacks face validity to most clinicians and is based on unrealistic extrapolations and invalid assumptions.

On the basis of the analysis by Makary and Daniel of hospital deaths in the US, The Guardian has reported that 9.5% of deaths are due to medical error (1); the Times says it’s 10% (2). Yet we know from robust case-note review studies (3) that in the UK 3.6% of inpatient deaths are related to adverse events and probably preventable.

Makary and Daniel’s analysis has misrepresented the true situation in 2 respects. Firstly, their extrapolations from the literature are unrealistic, based on flawed assumptions; secondly the single case study which they cite is unrepresentative of the majority of preventable hospital deaths.

Their figure of around 250,000 preventable deaths in the US is based on 4 studies. Two of these were in Medicare patients (4,5) who, being mostly elderly, would be expected to have a higher adverse event rate with more preventable deaths than the general hospital population; one (6) was in tertiary care centres which had a high rate of deaths due to adverse events (almost certainly due to a more complex case-mix) . All 9 deaths in these hospitals were also deemed preventable (most studies find 40-60% “preventable” deaths) but on the basis of these 9 cases the authors concluded that 400,000 deaths occurred across the US, which lacks credibility.

It is invalid to extrapolate, as the authors have done, from these selective populations to the general hospital population. (We could not find the reviewers comments on the BMJ website, but we are surprised that these methodological problems were not picked up at the review stage).

The single case study cited is also not representative and is potentially misleading. The mean age of those who die in hospital in England is 82 years (7); over 60% of preventable hospital deaths are in frail elderly patients with multiple co-morbidities (8) not young patients undergoing procedures, and decisions around “preventability” are much less clear cut than in the example given.

It is important to study hospital deaths so we can detect problems in care, learn from these and rectify deficiencies in order to improve. Systematic case record review of hospital deaths using a standardised qualitative methodology is the most useful way of doing this. The Royal College of Physicians has been commissioned by the Healthcare Quality Improvement Partnership on behalf of the NHS in England and Scotland to undertake such a programme, which will be launched later this year. There are also plans to extend the national Medical Examiner scheme to cover all areas of England and Wales (9). We would be surprised if either of these pieces of work find anything like the scale of problems described by these authors.

We are quick to object when politicians make unrealistic claims based on selective interpretation of statistics (10); we should be equally vocal when patient safety advocates do the same, no matter how well intentioned they are. It discredits our message amongst clinicians and diverts attention from the real aim of improving care for patients.


3.Hogan H et al. BMJ 2015;351:h3239 doi: 10.1136/bmj.h3239
4.Heathgrades quality study. Patient Safety in American Hospitals. 2004.
5.Department of Health and Human Services. Adverse events in hospitals; national incidence amongst Medicare beneficiaries. 2010.
6.Calssen et al. Health Affairs 30,No.4 (2011) 581-589
8.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 2012:21:737 41-45

Competing interests: KS and RB lead the Clinical Effectiveness & Evaluation Unit at the RCP which will be leading a national mortality case record review programme in England and Scotland.

05 May 2016
Kevin Stewart
Clinical Director
Rhona Buckingham, Mohsin Choudry
Clinical Effectiveness & Evaluation Unit
Royal College of Physicians, London NW1 4LE