Hospital Mortality: Association With Nurses’ Work Load and Education

Professor Linda H Aiken PhD, FAAN, FRCN, RN Claire M. Fagin Leadership Professor in Nursing, Professor of Sociology Director of the Center for Health Outcomes and Policy Research Center for Health Outcomes and Policy Research University of Pennsylvania School of Interview with:
Professor Linda H Aiken PhD, FAAN, FRCN, RN
Claire M. Fagin Leadership Professor in Nursing, Professor of Sociology
Director of the Center for Health Outcomes and Policy Research
Center for Health Outcomes and Policy Research
University of Pennsylvania School of Nursing Austerity measures and health-system redesign to minimise hospital expenditures risk adversely affecting patient outcomes. Against that backdrop, can you start by letting us know the background of the study?

 Prof. Aiken: European Surgical Outcomes Study in 28 countries showed higher than necessary deaths after surgery.

A comparable study in the US showed that despite the nation spending hundreds of millions of dollars on improving patient safety, there were no improvements in adverse outcomes after surgery in US hospitals between 2000 and 2009.  Clearly it is time to consider new solutions to improving hospital care for surgical patients, who make up a large proportion of all hospital admissions.  Our study was designed to determine whether there are risks for patients of reducing hospital nurse staffing, and what, if any, are the benefits to patients of moving to a more educated nurse workforce. Could you tell us a little about what the average workload of nurses were in the countries you studied is?

Prof. Aiken: The average patient to nurse ratio in hospitals in the 9 countries is 8.3 patients per nurse (which compares to about 5.5 in the USA) but these ratios varied from hospitals in which nurses care for 3 patients each to others where nurses care for 18 patients each.  On average nurses’ workloads are lowest in Norway and highest in Spain but within every country there is substantial variation in hospital nurse staffing.  In England with a national health service where standardization might be expected, the workloads of nurses in some hospitals were double those of others, ranging from 5 patients per nurse to over 11 patients per nurse.  It is this difference in nurse staffing levels across hospitals within every country that contributes to what we found to be a 7-fold difference in death rates after surgery for similar kinds of patients.   We found every one patient increase in a nurses work load was associated with a 7% increase in the risk of death for patients– which illustrates the hazards of increasing nurses’ workloads in attempts to save money.  These findings in Europe mirror the findings of papers we have published on nurses and mortality in the USA. Can you tell us a little more about your findings with regard to nurses’ education?

Prof. Aiken: Generally we think of educational attainment as a characteristic of an individual.  But the educational composition of a hospital’s nursing staff is also an attribute of an institution.  In Norway and Spain, all nurses must have a bachelor’s degree but in other countries, hospitals may employ nurses with and without university education.  There has been a contentious debate within the European Union on standardization of nursing education, and whether the goal of standardization should be the bachelor’s degree as in other professions.  Currently two very different levels of education for nurses are recognized within the EU:  nurses with 12 years of general schooling plus university education and nurses with only 10 years of general schooling followed by vocational training.  Like nurse staffing, the educational composition of nurses in hospitals varies substantially with some hospitals having no nurses with bachelor’s qualifications and some hospitals having 100% bachelor’s qualified nurses.  In England, for example, the NHS hospitals studied varied from 10% of bachelor’s educated nurses to 49%.  That hospital-level variation in the proportion of nurses with bachelor’s education was significantly associated with patient deaths, after taking into account other possible explanations including nurses’ workloads and how sick the patients were before surgery.  We found that every 10% increase in the proportion of nurses in a hospital with bachelor’s qualifications was associated with a 7% decline in patient deaths.  The Institute of Medicine of the National Academy of Sciences has acted upon our similar findings in the USA and has proposed that by 2020, at least 80% of USA nurses should hold the bachelor’s degree in nursing. Were there any unusual findings you’d like to comment on?

Prof. Aiken: Patients have the highest risk of death after surgery in hospitals where nurses with lower education care for more patients each.

Our most important finding for policymakers and consumers is that there is an unjustifiable difference in death rates following common surgery across hospitals in every country, and differences in nursing resources are a contributing factor to high death rates in many hospitals.

In every country there are well performing hospitals suggesting that even under less than optimal economic circumstances it is possible to achieve a high quality of hospital care.  A reasonable strategy to proceed in reducing preventable hospital deaths would appear to be improving nurse staffing in the hospitals in every country where nurses’ workloads are high, and transitioning to bachelor’s education for nurses.

Some might say that university education for nurses is not feasible for a variety of reasons.  The fact that both Norway, a well-resourced country, and Spain, a country struggling more to contain spending, could have successfully transitioned to an all university educated nurse workforce suggests that all countries in Europe could make the transition, and our results suggest that such a transition is in the public interest. What conclusions can be drawn from your results, and what are the implications for the future?

Prof. Aiken: While our study was immensely complicated to conduct, the conclusions and recommendations are remarkably simple.  Modern hospitals exist to provide 24 hour professional nursing care to people too sick to recover at home.  Thus it is foolish at best, and fatal at worst to under invest in nursing which is the primary service provided by hospitals.  Health reform initiatives and austerity measures, both of which tend to focus on reducing hospital nurses, put patients at serious risk of unnecessary death and other adverse outcomes.

Given the aging of Europe (and the USA), more nurses will be needed in the future.  It is unrealistic to expect the best and brightest of next generations to enter careers that do not provide a university education.  There won’t be enough talented and committed professional nurses to take on impossible burdens of unreasonable workloads and unsafe patient care.  Improving quality of hospital care now and for the future requires serious investments in professional nurses.


Aiken LH, Sloane DM, Bruyneel L, Van den Heede K, Griffiths P, Busse R, Diomidous M, Kinnunen J, Kozka M, Lesaffre E, McHugh M, Moreno-Casbas MT, Rafferty AM, Schwendimann R, Tishelman C, van Achterberg T, Sermeus W.  2014.  Association of nurse staffing and education with hospital mortality in 9 European countries.  The Lancet.  http// February 26, 2014.


Last Updated on March 19, 2014 by Marie Benz MD FAAD