Press Releases

2002 Releases

Nurse Staffing Levels Directly Impact Patient Health and Survival

Boston MA — The size and mix of nurse staffing in US hospitals has a direct impact on the outcome of patient health. The finding comes from the most comprehensive study to date on the topic and was led by Jack Needleman of the Harvard School of Public Health in Boston and Peter Buerhaus of Vanderbilt University’s School of Nursing in Nashville, Tennessee. The results appear in the May 30 issue of the New England Journal of Medicine.

Hospital discharge data for more than 6 million patients, financial reports and hospital staffing surveys from 799 hospitals in eleven states, including: California, New York, Maryland, Virginia, West Virginia, Arizona, Massachusetts, Missouri, Nevada, South Carolina, and Wisconsin. These data were analyzed to determine staffing levels of registered nurses (RN), licensed practicing/vocational nurses (LPN/LVN), and aides, and to measure the frequency of a wide range of complications that patients developed during their hospital stay.

Of the hospital inpatient nursing personnel studied, the study found that registered nurse staffing makes the biggest impact on patient outcomes. The researchers found relationships between nurse staffing and six adverse patient outcomes -- urinary tract infections, pneumonia, shock and cardiac arrest, upper gastrointestinal bleeding, "failure to rescue," and length of hospital stay -- in medical and major surgery patients treated in hospitals. They found higher RN staffing was associated with a 3 to 12 percent reduction in these adverse outcomes and higher staffing at all levels of nursing was associated with a 2 to 25 percent reduction in these adverse outcomes. (See table below. "Failure to rescue," as used in this study, is the death of a patient with one of five serious complications -- pneumonia, shock or cardiac arrest, upper gastrointestinal bleeding, sepsis, and deep vein thrombosis — for which early identification by nurses and medical and nursing interventions can influence the risk of death.) While the researchers found an association between nurse staffing and deaths in the failure to rescue category, they found no evidence of an association between nurse staffing and overall mortality among medical or surgical patients.

"The problem of low nurse staffing is serious at many hospitals, and its consequences for patients can be severe. Patient outcomes like hospital-acquired pneumonia, shock and cardiac arrest, and gastrointestinal bleeding have a substantial risk of death associated with them, and hospital-acquired urinary tract infections are far too common," said Jack Needleman, assistant professor at the Harvard School of Public Health and project director for the study, "The goal should be to reduce them to zero, if possible. Our study underscores that nurse staffing is an important element in improving patient safety."

"The study shows that nurse staffing matters considerably to the well-being of hospital patients," said Peter Buerhaus, co-project director for the study and senior associate Dean for research at Vanderbilt University’s School of Nursing. "There is a current shortage of hospital RNs and a much larger shortage is expected over the next ten to twenty years. Policy makers must make sure hospitals and nurses have the resources that will allow nurse staffing at levels that protect patient safety and reduce adverse outcomes. Nurses are the glue that holds the health care system together, and it is time that we invest more resources in the nursing profession"

The study was funded by the US Department of Health and Human Services, the Health Resources and Service Administration, Health Care Financing Administration, the Agency for Healthcare Research and Quality and the National Institute of Nursing Research of the National Institutes of Health.

Summary of association of lower nurse staffing and patient outcomes found by Needleman, Buerhaus, et al.

Patient Pool


Higher rate for outcome is associated with:

Difference in rate between low and high RN hospitals

Lower proportion of RNs


Fewer RN hours per day



Medical Patients

Length of Stay





Urinary tract infection





Upper gastrointestinal bleeding










Shock or cardiac arrest





Failure to rescue





Surgical Patients

Urinary tract infection





Failure to rescue





Source: Summarized from Needleman, Buerhaus, et al., "Nurse Staffing and Quality of Care in Hospitals in the United States," New England Journal of Medicine, May 30, 2002

Vanderbilt University Medical Center has built a strong reputation as a leader in medical education, research and patient care throughout the Southeast and the nation over the course of its history. The Vanderbilt University School of Nursing, founded in 1909, is one of the country's premier nursing schools preparing nursing students for diverse careers in advanced practice nursing.

For further information, please contact:

Robin Herman
Office of Communications
Harvard School of Public Health
677 Huntington Avenue
Boston, MA 02115
Phone: 617-432-4752

John Howser
Vanderbilt University Medical Center
Phone: 615-322-4747