Intended for healthcare professionals

Rapid response to:


Increased mortality associated with weekend hospital admission: a case for expanded seven day services?

BMJ 2015; 351 doi: (Published 05 September 2015) Cite this as: BMJ 2015;351:h4596

Rapid Response:

Statistical absurdity

Dear Editor

There are two key problems relating to both the 2012 and the 2015 studies(1, 2) which should not be ignored. Firstly the original Freemantle study states(2):

“Hospital stays on weekend days were associated with a lower risk of death than midweek days: hazard ratio for being in hospital on Sunday versus Wednesday 0.92 (95% CI 0.91 to 0.94; P < .0001), and for Saturday versus Wednesday 0.95 (95% CI 0.93 to 0.96; P < .0001). “

Thus one is approximately 6.5% less likely to die on a weekend day in hospital than on a midweek day. If one then assumes that all midweek days are like Wednesdays and that one can reduce the risk of death associated with a stay on a midweek day to that of a weekend day, this means that the number in hospital deaths (187,337) could be reduced to about 178,474 per year. By this logic there are approximately 8,863 ‘excess midweek deaths’ per year. This argument is clearly absurd; as absurd as Jeremy Hunt’s ‘11,000 preventable weekend deaths’ argument which is based on the same flawed approach.

Secondly the Freemantle studies describe between 50,000 and 80,000 in hospital deaths on Saturdays and Sundays(1, 2). Thus for the 8,000 ‘excess weekend effect deaths’ described by Pagano et al to be preventable it would make between 10% and 16% of weekend deaths preventable. In the context of the excellent recent research by Hogan et al demonstrating that only around 3% of deaths are actually ‘preventable’(3), it therefore appears that at a minimum the vast majority of the ‘weekend effect’ is as a result of residual confounding and is thus totally unavoidable.

Ignoring the most valid explanations for the ‘weekend effect’ and assuming that the cause is staffing levels appears worse than ‘rash and misleading’, it is both reckless and dangerous(4). Thus the research by Freemantle, Pagano, Keogh et al provides no plausible basis for the future structure of the NHS.


1. Freemantle N, Ray D, McNulty D, et al. Increased mortality associated with weekend hospital admission: a case for expanded seven day services? BMJ (Clinical research ed) 2015; 351.
2. Freemantle N, Richardson M, Wood J, et al. Weekend hospitalization and additional risk of death: an analysis of inpatient data. Journal of the Royal Society of Medicine 2012; 105(2): 74-84.
3. 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 (Clinical research ed) 2015; 351.
4. Weaver M CD. Guardian 2015;

Competing interests: No competing interests

21 October 2015
Benjamin JF Dean
Orthopaedic Registrar
Geraint E Thomas