Substituting nursing assistants for professional nurses in acute care hospitals in Europe is linked to poorer quality of care and increased mortality, according to a report published online November 15 in BMJ Quality & Safety.
Studies based on US hospital populations show that increasing the proportion of less highly trained nursing personnel adversely affects patient care. Data from European hospitals have been sparse, however.
Therefore, Linda H. Aiken, PhD, from the University of Pennsylvania School of Nursing, Center for Health Outcomes and Policy Research, Philadelphia, and colleagues analyzed the effect of increasing the proportion of less extensively trained nurses at 243 acute care hospitals in Belgium, England, Finland, Ireland, Spain, and Switzerland.
The researchers surveyed 13,077 nurses and 18,828 patients who had been in 182 hospitals between 2009 and 2010. They also consulted mortality records for 275,519 patients who had had surgery in 188 of the hospitals between 2007 and 2009.
During the study period, on average, 19 patients died after surgery per investigated hospital. The average hospital mortality rate was 12.8 per 1000 discharges.
The mean nurse skill mix, defined as the number of professional nurses divided by the number of direct care nursing workers of any qualification level during each professional nurse's most recent shift, was approximately 66%, but ranged from 41% to 87%.
Overall, 47% of the professional nurses in the study had bachelor's degrees, although they were unevenly distributed, with some hospitals having none. Nurses at hospitals with more professional nurses were less likely to report job dissatisfaction and burnout.
The average total nurse staffing-to-patient ratio, including professional nurses and nursing assistants, was 6.1 for every 25 patients, with a range of 2.7 to 13.8.
In a hospital that has average nurse staffing levels and skill mix, the researchers estimated that replacing one professional nurse with a lower-skilled worker increased the odds of a patient dying by 21%.
Conversely, each 10% increase in the proportion of nurses with high-level skills was associated with an 11% decrease in the odds of a patient dying postoperatively and a 10% decrease in the odds of a patient giving the hospital a low rating.
On average, 103 patients completed surveys in each hospital, with 54% giving their hospital a low rating. A mean of 54 nurses reported from each hospital, with 34% citing poor safety culture and 18% not recommending the hospital to friends or family. Moreover, job dissatisfaction and burnout overall each affected nearly a third of the participating nurses, at 31% and 30%, respectively.
Overall, the findings paralleled those from the United States. "We find a nursing skill mix in hospitals with a higher proportion of professional nurses is associated with significantly lower mortality, higher patient ratings of their care and fewer adverse care outcomes," the researchers write.
Limitations of the study include the observational, cross-sectional design and the focus on a single time. The study design also linked nurses and patients to the same hospitals, but not to each other.
The researchers conclude that the findings suggest "that caution should be taken in implementing policies to reduce hospital nursing skill mix because the consequences can be life-threatening for patients."
The researchers have disclosed no relevant financial relationships.