UTIs, pneumonia rise when nurses scarce

But HHS study can’t link staffing to mortality

The number and mix of nurses in a hospital makes a difference in whether patients acquire nosocomial urinary tract infections (UTIs) or pneumonia, according to a recent study by the Depart-ment of Health and Human Services (HHS).

While epidemiologists have been pointing out the link between staffing and infection rates for years, the massive study adds considerable clout to the issue at the federal level.

The study, Nurse Staffing and Patient Outcomes in Hospitals, is based on 1997 data from more than 5 million patient discharges from 799 hospitals in 11 states. It found a strong and consistent relationship between nurse staffing and five outcomes in medical patients: urinary tract infection, pneumonia, shock, upper gastrointestinal bleeding, and length of stay.

A higher number of registered nurses was associated with a 3% to 12% reduction in the rates of adverse outcomes, while higher staffing levels for all types of nurses was associated with a decrease in adverse outcomes from 2% to 25%. A multiple regression analysis tested potential indicators of patient outcomes associated with nurse staffing in inpatient acute care hospitals. Researchers found that the evidence was clearest of associations in regressions involving levels of RN staffing, or more commonly, a higher "RN share" in the nurse staffing mix. For example, both RN level and RN share influenced pneumonia rates.

In addition, the study found a link between UTIs in medical patients and staffing variables. Moving from low levels of staffing to high levels of all staffing variables was associated with a 4% to 25% reduction in the UTI rate. However, in somewhat of a surprise, no statistically significant relationship could be drawn between staffing and subsequent mortality or sepsis.

"Given the data limitations that make it hard to observe an association between nurse staffing and patient outcomes, and the difficulty of coding other outcomes of interest from these data sets, the outcomes we identified as associated with nurse staffing should be viewed as indicators or sentinel events, rather than as measures of the full impact of nurse staffing in the hospitals studied," the study said. With that finding, particularly with a national nursing shortage in the forecast, the report may eventually be the foundation for efforts to monitor outcomes of hospital care and levels of nurse staffing on an ongoing basis.

"Feeding this information back to hospitals can help guide efforts to improve the quality of care, modify nurse staffing, or make other changes," the HHS report concluded. "Routinely collecting and disseminating reliable data on patient outcomes also benefits consumers, employers, insurers, government, the media, and other interested parties by helping them make more informed choices and judgments when coming into contact with hospitals."

(Editor’s note: Copies of the study are available on the web at http://bhpr.hrsa.gov/dn/staffstudy.htm.)