The Weekend Effect: Fact or Fiction?
9 August 2016
This blog was originally posted as a Centre for Evidence Based Medicine blog
SHOULD WE LAY TO REST THE DAY OF REST?
Jeremy Hunt, the Secretary of State for Health, wishes to introduce a 7 day NHS, such that routine or elective services, not just emergency cover, are available on Saturdays and Sundays as well as the rest of the week. This has spurred discussion about what currently happens in hospitals and, in particular, how the number of deaths on weekdays compares with the number of deaths on weekend days. Hunt has stated that the lack of proper seven day services in hospitals results in 6,000 avoidable deaths each year. He has also said that you are 15% more likely to die if you are admitted to hospital on a Sunday compared to a Wednesday. We can think of some reasons why people who go to hospital at weekends might be more likely to die, but we need to look at the evidence to find out more. Do more peoplereally die in hospital at the weekend?
Where did Hunt get his evidence?
The Department of Health compiled their evidence from eight studies on ‘the weekend effect’. We looked at just the first of these, entitled ‘Increased mortality associated with weekend hospital admission: a case for expanded seven day services’. We wanted to see whether the results support the argument that there is a need to match weekday hospital services at weekends.
This paper is not suitable for bedtime reading. That we found it challenging to get our heads around this paper is an understatement! After several re-reads and much debate, below is our take on the pertinent findings.
Relevant results distilled
- A higher proportion of those admitted at the weekend (50% and 65% on Saturdays and Sundays, respectively) were emergency admissions, compared with those admitted during the week (29%).
- On Saturdays and Sundays, a larger proportion of patients admitted were in the highest risk of death category (25-29%), compared to those admitted on weekdays (under 20%).
Risk to patient according to day of the week
Principal analysis – using the number of deaths on a Wednesday as a benchmark, the risk of death within 30 days of admission was:
- higher by 2% for admission on a Friday
- higher by 10% for admission on Saturday
- higher by 15% for admission on a Sunday
- higher by 5% for admission on a Monday
Secondary outcome – again, using Wednesdays as a benchmark, and accounting for case mix and day of admission, the risk of dying was:
- higher by 2% on a Friday
- lower by 2% on a Saturday (borderline significant)
- lower by 1% on a Sunday (non-significant result)
- higher by 1% on a Monday (borderline significant)
It is unclear to us from reading this paper whether the risk of death within 30 days of admission was adjusted for case mix, that is, accounting for differences in death risk between patients. And if this adjustment was not made, we’d like to know why not. If this adjustment has been made, then Hunt’s statement about 15% increased risk of mortality on a Sunday can be said to hold true.
Interestingly, this paper is an update of a 2012 study performed by Fremantle et al, in which their principal analysis was based on time to in-hospital death. They found that being in hospital at the weekend is associated with reduced risk of dying (similar to the current paper). However, in the current paper, time to in-hospital death was relegated to a secondary outcome, with the authors citing that this outcome is biased by ‘informative censorship.’ We postulate that reporting of deaths/cause of death would be easier to find in the inpatient, compared with the outpatient setting. But that’s just our opinion…
The conflict of interest
The keen eyed among you may have noted that there is an erratum attached to this study, with a link to a conflict of interest statement; one of the authors has been a keen proponent of introducing a 7 day NHS model.
The long and short of it
It seems as though patients admitted at the weekend are more likely to be emergency patients and to have characteristics that place them in a higher risk of dying category (which seems intuitive). Patients already in hospital at the weekend are not at increased risk of death compared with those in hospital during the week, however, risk of death within 30 days of admission (whether this is in or out of hospital) is higher for patients admitted on Saturdays and Sundays (but also Fridays and Mondays) compared to those admitted on a Wednesday.
We feel that the reporting in this study could have been clearer; there were no confidence intervals found within the body of the text, and there was some ambiguity as to how certain analyses were performed. As such, it’s hard to draw any firm conclusions from this paper. We need more information, and a stiff coffee to boot.
Dr Oghenekome Gbinigie; MB BChir, MA (Cantab), MRCGP, DRCOG, DfSRH. Academic GP trainee, Nuffield Department for Primary Care Health Sciences, University of Oxford. Funded by the NIHR School for Primary Care Research.
Dr Elizabeth Spencer; MMedSci, PhD. Epidemiologist, Nuffield Department for Primary Care Health Sciences, University of Oxford.