The recently delivered Queen’s speech set out the government’s plan for “a 7-day NHS”. This vision is a reaction to alarming statistics that mortality rates are increased by 11% for patients admitted to hospital on a Saturday, and 16% if admitted on a Sunday, compared to patients admitted during the week. In a recent paper, I (along with my co-authors) examine the evidence base being used to support this policy move in more detail, and estimate the economic consequences in terms of the potential costs and benefits. The paper focuses on emergency hospital admissions, as this is the area in which the majority of these deaths occur and has been the focus of much of the policy debate.
The evidence base for seven day services
The highly quoted figure of a 16% increase in the risk of mortality is in fact a relative risk, which we all know too well can be misleading. When interpreting risk statistics the key piece of information is the baseline level of risk; figures which are omitted from the case for seven-day services. The most recent figures from England put the elevated mortality risk experienced by patients admitted to hospital in an emergency during the weekend at 0.3 percentage points. Whilst by no means trivial, it is doubtful that this alternative interpretation of the statistics would have summoned quite the same passion for a reorganisation of the entire English healthcare system.
The classic confusion between correlation and causation is the next mistake made when interpreting the ‘weekend effect’ literature. The association between reduced staffing levels in hospitals at weekends and elevated mortality has been cited as the root of the problem, despite a lack of causal evidence to this effect. In spite of this absence of supportive evidence, making routine services available seven days a week has been declared as the solution to tackling the observed weekend effect. The crucial question then, is what are the likely costs and benefits of such service extensions?
As economists we are familiar with the concept of opportunity cost, yet sadly it appears that politicians and policy makers have yet to grasp this key notion. Regardless of whether seven-day services are funded through a redistribution of current NHS budgets or an injection of new cash, this decision implicitly diverts potential resources away from patients admitted during the week. The average daily volume of patients admitted to hospital in an emergency is significantly higher on weekdays than during weekends. This means that staff would be diverted away from working at times of high patient volumes to times when there are fewer patients needing treatment. Yet these patients from whom resources are diverted away are never mentioned in arguments of fairness or equity. If, as the government suggest, staffing levels really are the key to reducing mortality, then the introduction of seven-day services may well narrow the gap between weekday and weekend mortality rates. However, it could easily do so by causing the weekday death rate to rise.
Potential benefits and costs of seven-day services
As healthcare policies such as seven-day services are funded from the same NHS budget as new treatments, they should be subject to the same cost-effectiveness evaluation as technologies seeking NICE approval. This requires rigorous evaluation of hard evidence, something seemingly neglected in favour of headline-hitting policy promises. In the paper we use the available evidence, albeit somewhat rudimentary, on the costs and benefits of introducing seven-day services in this setting to assess whether the policy change would likely pass a NICE assessment. We do so under the most optimistic assumption that this service change has the potential to completely eradicate the weekend effect.
Using methods described in detail in the paper, we estimate that reducing the mortality rate experienced by patients admitted in an emergency at the weekends to that observed during the week would result in an annual reduction of between 4,355 and 5,353 deaths occurring nationally (ceteris paribus, of course). This translates into a potential health gain of 29,727 – 36,539 QALYs per year if all of these deaths could be averted. Using the NICE threshold of £20,000 per QALY, the NHS should spend no more than £595m – £731m to achieve a health gain of this size.
Whilst the potential benefits of extending services appear large, they must be compared with the additional costs of doing so. Although caution was emphasised when producing the figures, the best available estimates of the costs of implementing seven-day services are those published by the NHS Seven Days a Week Forum. They estimate this to be 1.5% to 2% of total hospital income, equivalent to a 5% to 6% increase in the cost of emergency admissions. This translates to an annual cost of between £1.07bn and £1.43bn, exceeding our estimates of the maximum amount that the NHS should spend to eradicate the weekend effect by a factor of 1.5 to 2.4, or between £339m and £831m. To make matters worse, all of these calculations take place under the rather optimistic assumption that benefits to patients admitted at the weekend could be achieved without any detrimental effect on outcomes for those admitted during the week.
The way forward
Although alarming, the statistics on elevated weekend mortality are insufficient by themselves to justify a policy change towards extending normal hours of operation into the weekend. There is as yet no clear evidence: that seven-day working will, in isolation, reduce the weekend death rate; that lower weekend mortality rates can be achieved without increasing weekday death rates; or that such reorganisation is cost-effective.
A move towards a fully operational NHS service seven days a week has the potential to have impacts beyond reducing mortality, but these must be evidenced if the policy is to be supported. Mere suggestions that it may reduce factors such as readmission rates and hospital length of stay are not enough to justify a policy change, just as the verbal reassurance of a drug manufacturer that their product was able to cure cancer would not alone secure them NICE approval. Rigorous evidence and evaluation is needed in the policy sphere if we are truly to get the best use from our limited NHS resources. Evaluations of the implementation of seven-day services in the thirteen early adopters should be performed before national implementation is considered, just as any potential new treatment would be trialled before approval.
Disclaimer: The views and opinions expressed are those of the author and do not necessarily reflect those of the HS&DR programme, NIHR, NHS or the Department of Health.
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I think you are right to question whether the observed increases in mortality are a causal effect. The argument is that quality is reduced at the weekend leading to an increase in preventable mortality (if they weren’t preventable then there would be no case for 7 day NHS on this basis) resulting from an increase in preventable errors. However, research on preventable mortality and preventable adverse events and errors suggest that perhaps 8% of patients experience a preventable adverse event, of whom around 5% die. To account for the size of the change in mortality observed at the weekend, there would have to be an increase in the risk of experiencing an error or adverse event of almost 100% at the weekend, which would seem to me to be almost implausibly high. Certainly there are other arguments for a 7-day NHS (as pointed out in the comment above), but I’m not sure that the mortality argument is one.
Hard to argue with anything in this post, although it seems the key argument for 7 day working is not emergency care but the cost economy for elective care. The modernisation agency, years ago, demonstrated that elective care, with its man made variability, fluctuates much more than emergency care, and the daily variability in capacity is one barrier to patient flow.
A second unexamined argument is that the fixed cost of any given infrastructure can support greater volume of production if the assets are sweat over 7 days rather than 5. Hence many factories work 7 days across 4 shifts. Thus 7 day working has potential to reduce the unit costs of care (although staff will not be thrilled to hear that the best cost advantage comes if weekend working premia are also eliminated)
A third point relates to emergency care particularly: The rate that people become in need of treatment is in most cases unlikely to be correlated to the day of the week. Those low weekend volumes are likely to be related in part to less available GP services – hence Monday being the busiest day in primary care. So a truly 7 day primary care may even out this flow which, other things being equal, would then mean 7 day acute working was realigning both capacity AND demand, thus the impact on weekday patient staffing is addressed.
There is, however, one significant flaw in the last argument, which is key to the overall costs and benefits of 7 day working. When there is a bank holiday in England and primary care closes for an extra day, elective referral volumes go down, and are not compensated in thst week or month by higher referrals on the surrounding days. The reason supermarkets were keen to open on sundays was not only about smoothing consumer demand acctoss the week. They understood that they could see a growth in spend from the extra availability and convenience. What is unknown is how much additional treatment will take place as a result of the greater access that 7 day service provides. How many patients will be sent to hospital where watchful waiting might have been the best treatment? If there is a cobsequent reduction in treatment levels as the service access constraints on demand are lifted, that may be a significant addition to the costs of the policy.