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New analysis confirms a direct link between nurse staffing and patient complications and deaths in hospitals

Analysis of data on nurse staffing levels confirms that there is a direct link between the number of registered nurses (RNs) and the hours they spend with patients and whether patients develop a number of serious complications or die while in the hospital.

For the study, which was supported in part by the Agency for Healthcare Research and Quality (HS09958), investigators reexamined and refined their previous analysis released by the Health Resources and Services Administration (HRSA) in April 2001 as part of an ongoing collaboration within the Department of Health and Human Services to improve nursing care in American hospitals. The partnership also included AHRQ, the Centers for Medicare and Medicaid Services, and the National Institute for Nursing Research.

The research described in the original HRSA report and the new analysis were conducted by Jack Needleman, Ph.D., of the Harvard School of Public Health, and Peter Buerhaus, Ph.D., R.N., F.A.A.N., of the Vanderbilt University School of Nursing. Along with their colleagues, Drs. Needleman and Buerhaus reviewed their original discharge and staffing data from 799 hospitals in 11 States—California, New York, Maryland, Virginia, West Virginia, Arizona, Massachusetts, Missouri, Nevada, South Carolina, and Wisconsin—to estimate nurse staffing levels for RNs, licensed practical nurses (LPNs), and aides, as well as the frequency of a wide range of complications that patients developed during their hospital stay. These data cover 6 million patients discharged from hospitals in 1997.

Specifically, they confirmed their initial findings that low levels of RNs among a hospital's nurses were associated with higher rates of serious complications such as pneumonia, upper gastrointestinal bleeding, shock, and cardiac arrest, including deaths among patients with these three complications, as well as sepsis or deep vein thrombosis. These complications occurred 3 percent to 9 percent more often in hospitals with lower RN staffing levels than in hospitals with higher levels of RN staffing.

Both studies also found that rates for urinary tract infections, a less serious but common infection among hospital patients, and length of time spent in the hospital were also higher in hospitals with lower RN staffing. When comparing hospitals, the study controlled for how ill patients were in different hospitals and differences across hospitals in how likely patients were to suffer these complications.

Researchers again found an association between nurse staffing and deaths from more serious complications, but they found no evidence of an association between nurse staffing and overall deaths among medical or surgical patients. Low RN staffing at hospitals makes it more likely that some patients will suffer pneumonia, shock and cardiac arrest, and gastrointestinal bleeding, and that some patients may die as a result, according to the researchers. They conclude that more and better-educated nurses are needed to ensure that hospital patients don't suffer needlessly from complications. They also call for more research to identify the factors influencing nurse staffing levels and the mix of different types of nurses working in a particular hospital.

See "Nurse-staffing levels and the quality of care in hospitals," by Drs. Needleman and Buerhaus, Soeren Mattke, M.D., M.P.H., and others, in the May 30, 2002, New England Journal of Medicine 346(22), pp. 1715-1722.

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