Extended weekend working is being introduced by the National Health Service in a bid to save lives. But, as Matt Sutton and Rachel Meacock explain, new research casts serious doubt on the premise that more hospital staff on Saturday and Sunday will mean fewer patient deaths.

As the raft of recent media coverage has highlighted, hospital services at the weekend are being extended. Why? Because it is believed that patients are at higher risk of dying if they seek emergency care at the weekend.

This policy is based on research showing that the rate of mortality is higher amongst the patients who are admitted to hospital at the weekend, compared to those who are admitted during the week.

And it has been assumed – although, crucially, not demonstrated – that this is due to reduced availability of senior staff and diagnostic services in hospitals at weekends.

But findings from our latest research cast significant doubt over whether this is the case.

We have found that patients who attend A&E on weekends are at no higher mortality risk than patients who attend A&E on weekdays.

Our research reveals that smaller numbers of patients are admitted at the weekend, due to higher admission thresholds in A&E departments and reduced availability of primary care services.

A higher level of severity is needed to be admitted to hospital at weekends. Patients with non-serious illnesses are not admitted. Those who are admitted at the weekend are on average sicker than during the week and more likely to die, regardless of the quality of care they receive.

For our study we looked at all patients attending Accident and Emergency departments across England between April 2013 and February 2014 – whereas previous studies have considered only those patients who were admitted to hospital.

By examining deaths in hospital within 30 days of admission, we have found the death rate following a hospital admission at the weekend is higher only because the number of patients admitted to hospital at the weekend is lower.

Although similar numbers of patients attended A&E each day at weekends and weekdays, we found that hospitals admitted seven per cent fewer patients at the weekend.

As a result, the figures used to compare death rates at weekends and weekdays are skewed.

So the NHS has rushed to fix a perceived problem that our further research has shown simply does not exist. Patients attending A&E at the weekend are no more likely to die than patients attending A&E during the week.

The so-called ‘weekend effect’ is a statistical artefact and extending services is unlikely to reduce the number of deaths. Instead, the most likely impact of the planned service extensions will be an increase in the number of less severely ill patients who are admitted at the weekend, further pushing up NHS costs.

Extending services in hospitals and in the community at weekends may increase the number of emergency admissions, particularly for patients with less severe illness, and this could have the desired effect of securing lower hospital mortality rates.

But this would be a statistical phenomenon rather than a clinically meaningful improvement; it would be achieved by admitting more low severity patients rather than by reducing the absolute number of deaths.

• The full research paper, ‘Higher mortality rates amongst emergency patients admitted to hospital at weekends reflect a lower probability of admission’, is published in The Journal of Health Services Research and Policy. The research was conducted by The University of Manchester’s Centre for Health Economics.
• The project was funded by The National Institute for Health Research Health Services and Delivery Research (NIHR HS&DR) programme (project number 12/128/48). The views and opinions expressed are those of the authors and do not necessarily reflect those of the HS&DR programme, NIHR, NHS or the Department of Health.