A new review of NHS data led by a University Hospitals Birmingham NHS Foundation Trust (UHB) professor shows that patients admitted to hospitals at weekends are more likely to die within 30 days.

However, the likelihood of patients dying in hospital is less at the weekend than during the week.

These are the results of large-scale research published today (Friday 3 February 2012) in the Journal of the Royal Society of Medicine (JRSM).

The research team, led by Professor Domenico Pagano of the Quality and Outcomes Research Unit at UHB, analysed all 14.2 million admissions to NHS hospitals in England during the 12 months from April 2009 to March 2010.

For every 100 deaths among patients admitted to hospital on a Wednesday, 116 similar patients admitted on a Sunday would die. However, for every 100 deaths among patients in hospital on a Wednesday, 92 deaths would occur among similar patients already in hospital on a Sunday. The researchers believe that the scaling down of hospital services at the weekend may lead to fewer opportunities for patients to receive interventions and experience the adverse risks associated with these. The findings are consistent for both emergency and elective admissions.

Prof Pagano said: “These results offer conclusive evidence that confirms previous reports of increased 30-day mortality risk for patients admitted to hospital with emergency conditions at the weekend compared with the rest of the week. Previous reports, however, have not accounted for differences in patient characteristics associated with admissions on different days.”

The results of the analysis are also consistent with data from 254 not-for-profit hospitals in the United States, despite differences in the organisation and delivery of care between English and US hospitals.

Professor Pagano described several factors that might be associated with the increased risk of death for patients admitted with emergency conditions. Some may be more seriously ill, and had they been less ill would have had their admissions postponed until a weekday. He also speculated that there may be aspects of care at the weekend that disadvantage patients, such as reduced or altered staffing and skill mix; reduced availability of diagnostics; and less availability of senior staff to review cases and to be readily available for escalation.

The study also demonstrated an increased mortality risk over the 30 days' follow-up for patients admitted electively at weekends compared with similar patients admitted during the week. Professor Pagano said: “This could be because patients planned to have higher risk elective procedures at the beginning of the week are admitted over the previous weekend. Consequently the risk profile of elective patients admitted at weekends may be different and possibly higher from those admitted during the week.” The study analysed all deaths within 30 days from admissions, whether in or out of hospital. For emergency cases the ratio of in-hospital to out-of-hospital deaths is approximately 2:1, similar for admissions at weekends and during weekdays. For elective patients the ratio is 2:1 for those admitted at weekends but is almost reversed to 1:2 for those admitted during the week.

The researchers observed lower rates of in-hospital and out of hospital deaths during the weekend compared with during the week. Professor Pagano said: “This phenomenon must be due to the way services are organised since, all things being equal, we would expect a similar number of deaths on each day of the week.”

He concludes: “It may be that reorganised services providing seven-day access to all aspects of care could improve outcomes for higher risk patients currently admitted at the weekend. However, the economies for such a change need further evaluation to ensure that such reorganisation represents an efficient use of scarce resources.”