Patients' lives may be at risk if they are cared for in hospitals where nurses are poorly qualified or have heavier workloads, a major study in nine European countries has found.
Nursing cutbacks are directly linked to higher patient death rates in hospitals, researchers found.
Every extra patient added to a nurse's workload increases the risk of death within a month of surgery by 7 per cent, according to data from 300 European hospitals.
The highest risk of death after surgery was found in hospitals where nurses with lower levels of education cared for the most patients, researchers said.
A 10 per cent increase in the proportion of nurses holding a bachelor degree was associated with 7 per cent lower surgical death rates, according to the study published in the Lancet journal.
The study analysed information on more than 420,000 patients admitted to hospitals in Belgium, England, Finland, the Irish Republic, the Netherlands, Norway, Spain, Sweden, and Switzerland.
Data from English hospitals showed that on average every one of their nurses looked after around nine patients.
In some other countries the patient-to-nurse ratio was significantly smaller. Norway had a ratio of 5.2 to one, the Irish Republic 6.9, the Netherlands 7 and Finland and Sweden 7.6, 'The Guardian' quoted Press Association as reporting.
Spain appeared to have the most overworked staff, with an average 12.7 patients per nurse. But in Spain every nurse had a bachelor degree, compared with only 28 per cent in England at the time the data were collected in 2009-10.
"Our findings emphasise the risk to patients that could emerge in response to nurse staffing cuts under recent austerity measures, and suggest that an increased emphasis on bachelor's education for nurses could reduce hospital deaths," said US expert Professor Linda Aiken, from the University of Pennsylvania School of Nursing, who led the research.
Researchers compared hospitals where every nurse cared for an average of six patients and the proportion of degree-educated staff was at least 60 per cent, and those where nurses looked after eight patients each and just 30 per cent had bachelor degrees.
The hospitals with lighter workloads and more qualified nurses were expected to have 30 per cent lower surgical death rates, the study found.
"Our data suggest that a safe level of hospital nursing staff might help to reduce surgical mortality, and challenge the widely held view that nurses' experience is more important than their education," Aiken said.
