Low nurse and support staffing tied to higher inpatient mortality

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Low nursing assistant staffing is just as much of a risk to the lives of patients as inadequate registered nurse levels, US researchers have found. As well as reinforcing previous findings about the association between registered nurse staffing and patient mortality, the researchers also found a link between death rates and nursing support levels.

In addition, they determined that when patients are on a ward understaffed in both registered nurses and nursing support workers, the risk of them dying may be even more heightened.

The academics, from Columbia University School of Nursing, examined nursing staffing and in-hospital patient death data from 78,303 admissions across three hospitals in the US between 2007 to 2012.

For the purpose of the study, called "Association of registered nurse and nursing support staffing with inpatient hospital mortality" and published in BMJ Quality & Safety, understaffing was defined as levels 75% below what was typical for that unit during a day or night shift.

Associations between mortality and nursing staffing were analysed using Cox proportional hazards regressions models, which took into account patient variables such as age and gender.

The findings show low registered nurse and nursing support staffing were both associated with increased patient mortality.

When looking at the entirety of the patient’s stay, the death risk rate came out at 1.027 for every shift understaffed with registered nurses, and 1.030 for those with low nursing support cover. The rate sat at 1.025 when there were shortages in both professional groups.

During the second to fifth days of the patient’s admission, the mortality risk increased to 1.048 for shifts with low registered nurse staffing, and 1.032 for nurses’ assistants. When a shift had inadequate levels of both groups of staff, the risk rose substantially to 1.136.

The study also looked for links between high patient turnover and mortality but found no association between the two.

The authors said the findings raise questions about why low nursing support staffing was leading to an increased risk of patient death and suggested two possible theories. They said understaffing may inhibit nursing assistants from contributing to patient assessment and monitoring work and spotting when patients may need attention from other staff. It could also cause registered nurses to miss opportunities to assess and monitor patients because they are forced to carry out duties usually completed by their assistant workers.

“This mechanism is suggested by the limited literature examining RN assumption of transferable work, or work that is primarily the support staff’s, such as delivering and retrieving food trays, transporting patients, obtaining supplies and equipment and arranging transportation, and the role of low support staffing in increasing the work load of RNs,” said the study report.

“The impact of assumption of these necessary tasks and potential crowd out of other RN work can be linked to the growing literature on the role of missed care by RNs when staffing is low as a contributor to increased adverse events such as mortality.”

The authors of the study called for further research into these two theories. Commenting on the research, Patricia Stone, centennial professor of health policy at Columbia University School of Nursing, said: “both registered nurses and support staffing are important to ensure patient safety in hospitals, and this should be placed on the agenda of hospital administration executives, as low staffing levels can impact patient mortality.”

"The results should encourage hospital leadership to assure both adequate RN and nursing support staffing," the authors write.