Findings cast doubt on whether 7-day working week will curb excess deaths on Saturdays and Sundays in the UK.
The introduction of four priority standards for emergency care in hospitals in England has not made any difference to curbing excess deaths on Saturdays and Sundays, known as the 'weekend effect,' reveals the first study of its kind, published online in Emergency Medicine Journal.
The clinical standards, which are based on existing recommendations for best practice from national and international bodies, were introduced in 2015 to reduce the 'weekend effect.'
They focus on the speed and frequency with which patients are seen by senior doctors and their access to diagnostic tests and treatment on seven days of the week. They apply to between nine and 14 specialties.
Compliance with the standards by 2020 is mandatory for all hospitals in England, as part of the move to seven day working, with financial penalties threatened for those unable to meet them.
To find out if the adoption of these standards has lowered weekend death rates, and monitor the progress of seven day working, the researchers looked at the performance of 123 hospital trusts in England.
They used publicly available data on deaths within 30 days of admission to hospital against the four standards in 2015, as well as weekend death rates for the three years from 2013-14 to 2015-16.
Trust performance varied considerably: an average of eight out of nine eligible specialties met the consultant directed intervention standard (90 per cent), and just under five out of 10 (49 per cent) met the consultant review standard.
An average of seven out of 13 (54 per cent) specialties met the ongoing review standard, while nearly 11 out of 14 (76 per cent) met the access to diagnostic services standard.
Analysis of the figures showed that adoption of the four clinical standards wasn't associated with numbers of excess deaths among patients admitted on Saturdays and Sundays.
Nor was there any association between hospital trust performance against any of the four standards and the numbers of excess deaths on weekends or any changes in the weekend effect throughout the three years of the study.
The findings held true even after taking account of potentially influential factors, such as primary and secondary diagnoses, age, sex, level of deprivation, time of year, admission source (usual place of residence or other) or method (emergency or planned) and admissions over the previous year.
This is an observational study so no firm conclusions can be drawn about cause and effect, added to which the researchers analysed the number of specialties that met the standards, rather than which ones did so, and meeting these standards might be more important in some specialties than in others.
But they offer three possible explanations for the lack of associations they found between the standards and excess deaths at weekends.
These include poor quality data supplied by the hospital trusts; that the standards don't reduce excess weekend deaths; or that the weekend effect may be the wrong measure by which to judge the benefits of seven day services.
"These findings cast doubt on whether adoption of seven days clinical standards in the delivery of emergency hospital services will be successful in reducing the weekend effect," write the researchers, who go on to say that they "add to the increasing body of evidence questioning the link between levels of service provision and weekend death rates."
Complying with the standards may also divert care away from the most needy patients, and may not be the best way of using scarce NHS resources or of increasing the quality of care, they suggest.
They conclude, "The lack of association between the stated aims of the seven day services policy and the clinical standards being introduced to meet these aims suggests that the four priority clinical standards should be reviewed before compliance for all NHS hospitals is mandated in 2020."