The study comes at a sensitive time. Across Europe debate is raging over austerity policies and public spending cuts, including cuts in hospital funding. The study may also fuel debate on the role of nursing in modern health care. Training and employing university-qualified nurses is a high-cost option and runs counter to established practice in German-speaking and Eastern European countries, where hierarchical systems look to nurses mainly to carry out the physical tasks of hospital care.
The study, by a consortium of European and American researchers, looked at patient files and nurses’ qualifications at 300 hospitals across nine European countries. After adjusting for factors unrelated to the nursing staff — for example, the severity of patients’ illnesses — it found that each 10 percent increase in the percentile of the nursing staff with a bachelor’s degree (for example, from 50 percent to 55 percent) was associated with a 7 percent decrease of mortality among the associated patient group.
Patients covered by the study were aged 50 or older and admitted to a hospital for at least two days for common general, orthopedic or vascular surgery.
The researchers also found that for every one-patient increase in the number of patients per nurse there was an associated 7 percent increase in patient death rates. The mean ratio for the hospitals in the study was 8.3 patients per nurse, with national variations around the mean ranging from 5.2 patients per nurse in Norway to 12.7 in Spain.
The mean mortality rate in the patient target group across the nine countries was 1.3 percent. At the low end, participating hospitals in Sweden had a 1.0 percent mortality rate among the defined patients, while the institutions that participated in the Netherlands, Ireland, Norway and Switzerland had mortality rates closer to 1.5 percent.
The study mined data for 422,730 patients — nearly everybody in the target age group admitted for surgery at participating hospitals in the Netherlands, Belgium, England, Ireland, Norway, Spain, Sweden and Switzerland.
Nurses were asked specifically for their highest level of nursing education. Other academic degrees and qualifications were ignored.
While nursing education varies from country to country, a current European guideline stipulates that nurses should have a minimum of 4,600 hours of relevant training, spread over three years, of which half should be spent training in a clinical setting.
Because of this guideline, formalized in a European Union directive, and the similarity of university-level nursing degree courses across Europe, the study’s authors said they were confident in the comparability across national frontiers of the data they examined.
“Despite variations in health system design and difference in education, these trends hold true,” said Mathew McHugh, one the study’s authors and a professor at the University of Pennsylvania School of Nursing.
Dr. McHugh said great care was taken to find a metric that could compare hospital outcomes across different healthcare systems: Some major countries, among them Germany, were excluded from the Lancet study because data on comorbidity — deaths in hospital resulting from causes such as long-term disorders or diseases for which a patient was not admitted nor expressly treated — was not sufficiently complete.
Why the difference between university-educated and vocationally trained nurses should influence patient death rates is a matter of debate. Some experts say that bachelor-level nurses are better at monitoring and documenting changes in patients.
“We know that nursing matters, and it is a ripe place to look if you want to drive quality of care,” Dr. McHugh said.
Half a century ago, nurses were mostly seen as basic caregivers; but increasingly European health care systems have come to rely on university-trained nurses to understand patients’ medical problems, coordinate care and participate actively in the professional discussions of the medical care team.
Unlike hospitals in Norway or Spain, which are completely staffed by university-trained nurses, hospitals in the Netherlands are staffed with nurses who have both types of educational background.
“Once you know whether they are vocational or have a bachelor’s, you do notice the difference,” said Ilona Douwes, a neonatal intensive care nurse in the group at the Radboud hospital.
The theoretical medical knowledge of nurses with bachelor’s degrees and their willingness to question the chain of authority over possible errors could contribute to the higher success rate of hospitals employing them, said Dr. Marieke Schuurmans, a professor at the University Medical Center Utrecht and the University of Applied Sciences Utrecht in the Netherlands who teaches both vocational and bachelor-level nurses.
Theo van Achterberg, the Dutch country coordinator of the study, agrees that university-trained nurses might simply be better at catching mistakes: “They might more easily question what physicians say,” he said.