Study Examines Association between Nurse Staffing Levels and Patient Mortality in VA Hospitals
- RN staffing was not significantly associated with in-hospital mortality for veterans with an ICU stay; however, increased RN staffing was significantly associated with decreased mortality among non-ICU patients.
- RN hours per patient day appear very differently distributed when analyzed at the hospital level compared with the unit level. At the hospital level, there is little difference in RN hours per patient day between patients who have an ICU stay compared with those who do not (6.8 vs. 6.4 RN hours per patient day); however, at the unit level the difference is 18.5 vs. 4.9 RN hours per patient day.
- Authors suggest that it is possible to evaluate the effect of nurse staffing factors on patient outcomes, but with more comprehensive data, such as data that link patients directly with the nursing care they receive. Continuing to estimate the effect of RN staffing and skill mix on patient outcomes using hospital-level data will provide poor estimates of outcome associations, such as in-hospital mortality.
NOTE: This article demonstrates the substantial, as yet unrealized potential, for utilizing nursing level data to evaluate and improve quality of care.
Nurse staffing is not the same across all units in a hospital, and intensity of care differs across unit types – from general inpatient acute care to intensive care. This retrospective observational study evaluated the association between in-hospital patient mortality and registered nurse staffing and skill mix (e.g., proportion of total nursing hours provided by RNs). Using VA data, investigators assessed in-hospital mortality for 129,579 veterans who were treated on 453 nursing units (171 ICU and 282 non-ICU) in 123 VA hospitals. This study also assessed whether the association between nursing factors and in-hospital mortality is affected by analyzing at the hospital or unit level.
- For veterans with an ICU stay, investigators weren’t able to obtain physiological data to control for severity of illness that is critical for risk-adjustment in this population.
- Some veterans in this study moved from one unit to another, usually between non-ICU and ICU. Assigning them unit characteristics of the ICU they stayed in may mask the effect of nursing variables on all of the units they were treated on.
This study was funded by HSR&D. At the time of this study, Dr. Sales was part of HSR&D’s Northwest Center for Outcomes Research in Older Adults. Drs. Sharp, Li, Lowy, Greiner, and Liu are part of the VA Puget Sound Health Care System; Dr. Alt-White and Ms. Rick are part of the Office of Nursing Services, VA Central Office; Dr. Rosenthal is with the Iowa City VA Medical Center.
Sales A, Sharp N, Li Y, Lowy E, Greiner G, Liu C, Alt-White A, Rick C, Sochalski J, Mitchell P, Rosenthal G, Stetler C, Cournoyer P, Needleman J. The association between nursing factors and patient mortality in the Veterans Health Administration: the view from the nursing unit level. Medical Care 2008 Sep;46(9):938-45.