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Patients Undergoing Major Surgery in Hospitals with Limited Nursing Staffs Suffer More Complications

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Press Release Date: December 4, 1998

Patients who have surgery done in hospitals that have fewer registered nurses per patient than other hospitals run a higher risk of developing avoidable complications following their operations, according to a new study by researchers at the U.S. Agency for Health Care Policy and Research (AHCPR) published in the nursing journal, Image.

The study found hospitals that provided 1 more hour of nursing care per patient day (than the average nursing care hours per patient day) had almost 10 percent fewer patients with urinary tract infections and 8 percent fewer patients with pneumonia. One hour more per day of nursing care is about a 17 percent increase in nurse staffing levels.

After analyzing data from 506 hospitals in 10 states, Christine Kovner, Ph.D., R.N., an associate professor with New York University, and AHCPR researcher Peter Gergen, M.D., M.P.H., found that the fewer full-time equivalent registered nurses per inpatient day a hospital has, the greater is its incidence of urinary tract infection, pneumonia, thrombosis—formation of blood clots—pulmonary congestion and other lung-related problems following major surgery.

These are complications that nurses can often prevent by getting patients out of bed and walking after surgery, by monitoring them closely and through other hands-on nursing skills.

"Studies like this demonstrate that it is critical to study the outcomes and effectiveness of changes in the organization and delivery of health care services," said AHCPR Administrator John M. Eisenberg, M.D. "This information is as important to improved health care quality as is information about the outcomes and effectiveness of medical treatments. AHCPR is dedicated to providing the scientific evidence that clinicians, health care systems leaders and policymakers need to correct quality problems, such as avoidable complications and medication errors."

According to Dr. Kovner, who at the time of the study served as a Senior Nurse Scholar with AHCPR, the finding of a strong inverse relationship between registered nurse staffing and adverse patient events should be considered when developing strategies to reduce costs. Dr. Kovner said that about 1.2 million registered nurses work in hospitals, where they make up nearly a quarter of hospital staff and constitute their single largest labor cost.

Among the study's other findings were that large hospitals have significantly lower urinary tract infection rates than smaller ones; large and medium-sized hospitals have higher rates of lung-related disorders than smaller facilities; and both public and not-for-profit hospitals have significantly lower urinary tract infection rates than do for-profit hospitals.

The researchers based their findings on 1993 discharge data from AHCPR's Nationwide Inpatient Sample—a component of the agency's Healthcare Cost and Utilization Project (HCUP)— which they linked to data on hospital characteristics from the American Hospital Association's 1993 Annual Survey of Hospitals. The investigators also used AHCPR's HCUP Quality Indicators—software that provides information about outcomes of patient care, utilization of inpatient services and access to care in a community—to identify the procedures they wanted to examine.

Details are in "The Relationship Between Nurse Staffing Level and Adverse Events Following Surgery in Acute Care Hospitals," which appears in the Fourth Quarter 1998 issue of the nursing journal, Image.

For more information on AHCPR studies and research resources such as the Nationwide Inpatient Sample and HCUP Quality Indicators, visit the agency's Web site at

Note to Editors: For interviews with Dr. Kovner, call David Caruba, director of communications for NYU's Division of Nursing: (212) 998-5612 (office); (917) 897-9521 (beeper).

For additional information, contact AHCPR Public Affairs: Karen Migdail, (301) 427-1855 (

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