Stroke patients are more likely to die in units with lower nurse staffing levels at weekends, according to latest UK research.

It is the first time that researchers have looked specifically at the effect of staffing levels on patient mortality in stroke units.

Introducing seven day working across the acute sector has been identified as a policy priority by the government and NHS England due to evidence of poorer patient outcomes at weekends.

The researchers said observational studies had reported higher mortality for stroke patients admitted on weekends, but it was not previously known whether this “weekend effect” was influenced by clinical staffing levels.

Using data from the Royal College of Physician’s stroke programme, they analysed data from 56,666 patients admitted to 103 stroke units in England between June 2011 and December 2012. 

They found that patients admitted to hospitals with the lowest weekend ratios of registered nurses to patient beds had the highest mortality risk.

Patients admitted to a stroke unit with 1.5 registered nurses per 10 beds had an estimated adjusted 30-day mortality risk of 15.2 per cent, compared to 11.2 per cent for those in units with three nurses per 10 beds – equivalent to one excess death per 25 admissions.

A “very similar” association regarding weekend nursing levels was observed for patients admitted on weekdays, said the study authors in the journal PLOS Medicine.

However, the impact of doctors was less clear, as patient mortality risk did not differ whether stroke specialist physician rounds were seven days per week or fewer than seven days.

The study authors, led by researchers from King’s College London, said: “Weekend nursing ratios were strongly associated with mortality outcomes, not only for patients admitted on a weekend but also for those admitted on a weekday.

“These data support the provision of higher weekend registered nurse/bed ratios in [stroke units],” they said.

The results add to a growing body of recent evidence demonstrating the impact on care of variations in nurse staffing levels, including the seminal RN4CAST study into Europe’s nursing workforce.

The Royal College of Nursing said the new study was “further evidence of the vital importance of having proper nurse staffing levels to ensure good patient care”.

Peter Carter, RCN chief executive and general secretary, said: “These findings reinforce what we already know – only with the right number of nurses, with the right skills, can we ensure patients are properly looked after with dignity and compassion.

“The reports of Sir Robert Francis and Sir Bruce Keogh, among others, also demonstrated that unsafe staffing levels jeopardise patient safety,” he added.