Study links the 'weekend effect' of increased hospital mortality to junior doctors admitting a lower proportion of healthy patients at the weekend compared to weekdays.
It's clear that the admitting behaviour of junior doctors changes at the weekend
Stefan Scholtes
The "weekend effect" of increased hospital mortality has been well documented, including a 2015 study linking this to 11,000 extra UK deaths annually, which led to controversial contract changes for junior doctors as the UK government sought a "seven-day" National Health Service.
But the underlying causes have been poorly understood: are hospitals less safe on weekends or do other factors lead to a comparison-skewing weekday reduction of the risk of mortality?
A new study led by University of Cambridge researchers, based on nearly 425,000 emergency room attendances over seven years at Addenbrooke's Hospital in Cambridge, confirms the weekend effect and finds that hospital admitting practices by junior doctors may be driving it. The results are reported in the Emergency Medicine Journal.
The research found that junior doctors (qualified doctors still in training) based in the emergency department admitted relatively healthy patients (those deemed as "standard" or non-urgent cases) at half the rate at weekends compared to weekdays, diluting the risk pool of weekday admissions and contributing to the weekend effect.
The study suggests one reason junior doctors may over-admit low-risk patients on weekdays is a feeling that higher Monday-to-Friday resource availability can handle the extra patient load.
In contrast, the admitting behaviour of senior doctors was the same on weekends and weekdays, and the data did not provide evidence of a weekend effect among patients admitted by senior doctors.
The researchers found that the weekend effect was associated with seniority of the emergency department physician, that the case-mix of patients at the weekend was more ill, and that junior doctors admitted fewer standard patients at the weekend than on weekdays.
In light of the study's findings, the authors recommend that the admitting behaviour of both junior and senior doctors be assessed to determine if hospital services are being used appropriately.
"There has been previous research on how physician-level factors influence patient care, but our study instead focuses specifically on how seniority affects admitting behaviour and in turn how this relates to the weekend effect," said co-author Stefan Scholtes, Dennis Gillings Professor of Health Management at Cambridge Judge Business School. "It's clear that the admitting behaviour of junior doctors changes at the weekend."
In a commentary about the new study, also published in Emergency Medicine Journal, the President of the Royal College of Emergency Medicine, Dr Katherine Henderson, said the study had "given us a lot to think about" - describing as "surprising" the finding about junior doctors admitting more relatively well patients on weekdays.
"The NHS needs to use its resources as effectively as possible," she wrote. "We should only admit patients who need to be admitted. This paper suggests it would be a good idea to make sure we are using our senior decision makers where they can be most valuable - seeing sick patients and actively evaluating all borderline admission/discharge decisions."
The study examined detailed records of Cambridge University Hospitals between 2007 and 2013, in which 229,401 patients made 424,845 emergency department visits - of which 158,396 were admitted to the hospital.
The case mix of admitted patients was more ill at weekends, with 6.4 per cent requiring immediate resuscitation compared to 5.4 per cent on a weekday; such a seemingly small difference played an outsized role in the weekend effect, as 11.1 per cent of patients requiring immediate resuscitation died within 30 days of arrival at the emergency department. Of all patients admitted on a weekend, 3.7 per cent died within 30 days, compared to 3.3 per cent of patients admitted on a weekday.
While senior doctors admitted about the same proportion of their patients on weekdays and weekends (24.8 per cent and 24.0 per cent, respectively), junior doctors admitted 61.7 per cent of patients on weekdays and 44.2 per cent at weekends.
Crude mortality rates for admitted patients were not statistically different for junior doctors (3.5 per cent) or senior doctors (3.3 per cent). While the crude mortality rate for patients treated by senior doctors on weekends and weekdays was identical at 3.3 per cent, the rate for junior doctors was 4.0 per cent on weekends and 3.3 per cent on weekdays.
The study is co-authored by Larry Han of Cambridge Judge Business School and Harvard University's Department of Biostatistics; Jason Fine of the University of North Carolina; Susan M. Robinson and Adrian A. Boyle of the Emergency Department at Cambridge University Hospitals NHS Foundation Trust; Michael Freeman of Cambridge Judge Business School and INSEAD Singapore; and Stefan Scholtes of Cambridge Judge Business School.
Reference:
Larry Han et al. 'Is seniority of emergency physician associated with the weekend mortality effect? An exploratory analysis of electronic health records in the UK.' Emergency Medicine Journal (2019). DOI: 10.1136/emermed-2018-208114
