Inpatient mortality goes up significantly when a hospital has greater patient turnover and when it fails to meet its own nurse staffing targets by at least eight hours, says a report that strongly suggests hospitals measure and adjust nurse staffing to patient needs.
"We estimate that the risk of death increased by 2% for each below-target (8-hour) shift and 4% for each high turnover shift to which a patient was exposed," said the report, by first author Jack Needleman, professor of health services at UCLA School of Public Health, and colleagues at the University of California Los Angeles, Vanderbilt University, the Mayo Clinic and Duke University Medical Center.
The mortality risk for patients exposed to three nursing shifts that fell below target levels was 6% higher than for patients on units that were fully staffed.
"Staffing projection models rarely account for the effect on workload of admissions, discharges and transfers," the report said, which greatly increase the amount of time required for each patient.
The reportis published Thursday's New England Journal of Medicine.
The team looked at 197,961 electronic rather than administrative records for patients across 43 patient care units at an unnamed large academic U.S. tertiary hospital for the period between 2003 and 2006, comparing a hospital against itself.
In an interview, Needleman says that previous studies that evaluated mortality and nursing staff compared hospitals with high staffing ratios against ones with low staffing.
"People pushed back on that," Needleman says. "They said well, maybe it's not the staffing, maybe something else about the hospitals: the doctors and nurses aren't as good or the equipment wasn't good or hospital management doesn't have the same commitment to quality. And this is just an artifact of data. Or you can't do enough risk adjustment across the hospitals."