Nursing skill mix in European hospitals: cross-sectional study of the association with mortality, patient ratings, and quality of care

In BMJ Quality & Safety, Linda Aiken and colleagues, including Matthew McHugh examine the association of hospital nursing skill mix with patient mortality, patient ratings of care, and indicators of quality care among European hospitals. As policymakers around the world seek to reduce health spending, a popular target in Europe has been to transition from more professional nurses to fewer high-cost nurses supported by more lower-wage assistants. The authors analyzed how nursing skill mix affects indicators of quality patient care. The authors utilized cross-sectional patient discharge data, hospital characteristics, and nurse and patient survey data from adult hospitals in six European countries – Belgium, England, Finland, Ireland, Spain, and Switzerland. Survey data were collected from 13,077 nurses in 243 hospitals, and 18,828 patients in 182 of those same hospitals.

The authors find that a richer nursing skill mix is associated with lower odds of mortality, lower odds of low hospital ratings from nurses, and lower odds of poor quality and safety grades. Furthermore, each 10 percentage point reduction in the proportion of professional nurses is associated with an 11 percent increase in the odds of death. Substituting one nurse assistant for a professional nurse for every 25 patients is associated with a 21 percent increase in the odds of death. The authors conclude that a bedside care workforce with a greater proportion of professional nurses is associated with better outcomes for patients and nurses. Reducing nursing skill mix by adding nursing assistants without professional qualifications may contribute to preventable deaths and erode quality and safety of hospital care.