The weekend effect—how strong is the evidence?
BMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i2781 (Published 19 May 2016) Cite this as: BMJ 2016;353:i2781
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I read that the data is open to varying interpretation and note confusion from the prime minister down in respect of 'seven day working'. The requirements of scheduled and unscheduled care are the same only in terms of the quality of service that should be offered to patients and the former self-evidently does not have to be provided 'out of hours'. The need to ensure a consistent high standard of unscheduled care 24/7 across the NHS is bleeding obvious and should be a given. We need to ensure this by effecting a rejjig and reclassification of medical care and think a little outside the box in terms of how we might use other health professionals.
Competing interests: No competing interests
We wonder if a large part of what is missing in this debate is the interplay between social care, primary care and hospitals out of hours.
Those who experience a social care crisis out of hours can be admitted to hospital inappropriately. The popular assumption is that the government have underfunded social care to the point where there is no room for alternatives.
This is especially relevant in a speciality like psychiatry where placement breakdowns may result in people coming into emergency departments.
We need to include social care and primary care in the debate about what a 7 day service would or should look like.
Preventing admissions by increasing out of hospital options may be a better way of reducing pressures in hospital.
Competing interests: No competing interests
In the pursuit of definitive evidence for or against the weekend effect we must guard against seeking a precise answer to the wrong question as opposed to an approximate answer to the right question.. In my view the crucial question is whether or not a seven day service is compliant with the core values of the profession, which include a compassionate recognition of the distress that patients experience when the availability of NHS services such as emergency endoscopy or imaging modalities is demonstrably not the same at weekends as it is on weekdays.
Consequences of suboptimal availability include an unnecessarily longer hospital stay, with resulting risk of complications such as hospital acquired infections, falls, and delirium for elderly patients (who now constitute the majority of hospital inpatients), as opposed to the hard point of mortality risk. If, however, the precise answer we want is the end point of mortality risk we run the risk of seeking a precise answer to the wrong question.
Competing interests: No competing interests
Unfortunately I have been misquoted in the article. The inability of administrative data (Hospital Episode Statistics) to be used to make meaningful comparisons of outcomes by day of the week is not because "There is nothing in the coding about comorbidity” but due to the absence of any data on the severity of the condition for which the patient was admitted. Comorbidity data present a different shortcoming - they are included but are probably wrong (eg patients at weekends are reported as suffering less comorbidity than those admitted during the week).
Competing interests: No competing interests
Why are weekend emergency admissions lower than weekdays?
If we are to understand the ‘week-end effect’ this question could be the most important question to answer, yet it does not seem to have been adequately addressed by current research. Do patients really get to choose on which day they have an emergency? Why is there this difference in admission rates?
Consider the following two scenarios: a patient develops a dense hemiplegia affecting the right arm and face compared with a patient developing tingling in the face and right arm. Which of these two patients is most likely to present to hospital on the day the symptoms arise?
Any GP will tell you there are a proportion of patients who will develop symptoms at a weekend and not present to their GP until the Monday or Tuesday. This is far more likely if the symptoms are at the mild end of the spectrum when the patient interprets them as being less serious.
There are two points that arise from this. The first is that mild symptoms are associated with longer survival and these long survivors are in effect being shifted from the weekend statistics to the week days. This increases mortality rates for the weekends and decreases it for the weekdays. Is there any evidence for this sort of shift? The PLOS one paper [1], one of the few that gives a daily breakdown of admission, shows that admissions for strokes on a weekend are 16% lower than average, yet on a Monday and Tuesday they are 11% higher - although this does not characterise the types of patients being shifted.
The second point is that a few studies have claimed they have controlled for case-mix differences in their respective models [2,3]. This usually takes the form of including covariates that capture co-morbidities such as hypertension or diabetes, demographic factors such as age, numbers of previous admissions, deprivation scores, and so on. Such data are often well coded; however, the difference between the 2 scenarios described lies in the presenting symptomatology. It is very unlikely that presenting symptoms will be captured in the hospital coding. Thus, the models so far are unable to distinguish between cases such as the ones described. This is important, particularly if this could potentially affect the day the patient presents.
To their credit Meacock et al [4] have considered the question of why there may be difference between admission rates. They examined the differences between patients attending A&E and those being admitted for the weekend and weekdays and concluded that there was higher threshold for admission on a weekend. This would act as relative filter where patients presenting with mild symptoms on a weekend would be less likely to be admitted.
This would suggest that there are at least two mechanisms that would lead to a difference in admission rates. These need to be explored more extensively before the sort of strong assertions that have been made on the existence of a ‘weekend effect’ should have been made. It may end up being a statistical artefact.
The BMJ should bear some of the responsibility on this. The journal has published several articles in support of a ‘weekend effect’ one in which the statistical reviewer was asked to review on no fewer than three occasions despite expressing reservations on the analysis (the reviews are available on-line) [5]. The editor in an editorial said the evidence ‘sent a consistent message: an association between admission to hospital at weekends and a higher risk of death’ implying a ‘weekend effect’ [6]. It is incredible therefore that it did not publish the article by Meacock et al which offers a reasonable counter to the ‘weekend effect’ [4] and raises suspicions of an editorial policy that is in favour of the ‘effect’. This has been a politically charged issue which has received widespread coverage in the press and the journal editors need to re-examine whether they have prioritised sensationalism over objectivity.
Reference
1. : Roberts SE, Thorne K, Akbari A, Samuel DG, Williams JG (2015) Mortality following Stroke, the Weekend Effect and Related Factors: Record Linkage Study. PLoS ONE 10(6): e0131836. doi:10.1371/journal.pone.0131836
2. Freemantle N, Ray D, McNulty D, Rosser D, Bennett S, Keogh BE, Pagano D. Increased mortality associated with weekend hospital admission: a case for expanded seven day services? BMJ. 2015 Sep 5;351:h4596. doi: 10.1136/bmj.h4596
3. Aldridge C, Bion J, Boyal A, Chen YF, Clancy M, Evans T, et al. Weekend specialist intensity and admission mortality in acute hospital trusts in England: a cross-sectional study. Lancet. 2016 May 10. pii: S0140-6736(16)30442-1.
4. Meacock R, Anselmi L, Kristensen SR, Doran T, Sutton M. Higher mortality rates amongst emergency patients admitted to hospital at weekends reflect a lower probability of admission. J Health Serv Res Policy OnlineFirst, published on May 6, 2016 as doi:10.1177/1355819616649630
5. Palmer W, Bottle A, Aylin P. Association between day of delivery and obstetric outcomes: observational study. BMJ 2015;351:h5774
6. Godlee F. How Jeremy Hunt derailed clinician led progress towards a seven day NHS. BMJ. 2016 Jan 13;352:i187. doi: 10.1136/bmj.i187.
Competing interests: No competing interests