Context: Nurse staffing is not the same across an entire hospital. Nursing care is delivered in geographically-based units, with wide variation in staffing levels. In particular, staffing in intensive care is much richer than in nonintensive care acute units.
Objective: To evaluate the association of in-hospital patient mortality with registered nurse staffing and skill mix comparing hospital and unit level analysis using data from the Veterans Health Administration (VHA).
Design, Settings, and Patients: A retrospective observational study using administrative data from 129,579 patients from 453 nursing units (171 ICU and 282 non-ICU) in 123 VHA hospitals.
Methods: We used hierarchical multilevel regression models to adjust for patient, unit, and hospital characteristics, stratifying by whether or not patients had an ICU stay during admission.
Main Outcome Measure: In-hospital mortality.
Results: Of the 129,579 patients, mortality was 2.9% overall: 6.7% for patients with an ICU stay compared with 1.6% for those without. Whether the analysis was done at the hospital or unit level affected findings. RN staffing was not significantly associated with in-hospital mortality for patients with an ICU stay (OR, 1.02; 95% CI, 0.99–1.03). For non-ICU patients, increased RN staffing was significantly associated with decreased mortality risk (OR, 0.91; 95% CI, 0.86–0.96). RN education was not significantly associated with mortality.
Conclusions: Our findings suggest that the association between RN staffing and skill mix and in-hospital patient mortality depends on whether the analysis is conducted at the hospital or unit level. Variable staffing on non-ICU units may significantly contribute to in-hospital mortality risk.
From the *Faculty of Nursing, University of Alberta; †VA Puget Sound Health Care System; ‡Department of Health Services, University of Washington; §Office of Nursing Services, VA Central Office, Washington, DC; ¶School of Nursing, University of Pennsylvania; ∥Department of Biobehavioral Nursing and Health Systems, University of Washington; **University of Iowa; ††Iowa City VA Medical Center; and ‡‡University of California at Los Angeles.
Supported by the Office of Research and Development, Health Services R&D Service, Department of Veterans Affairs, project number IIR 01-160.
The views expressed are those of the authors and do not reflect the views of the Department of Veterans Affairs.
Dr. Sales was an investigator at the Northwest HSR&D Center of Excellence at VA Puget Sound Health Care System at the time of this study, and had full access to all of the data in the study. She takes responsibility for the integrity of the data and the accuracy of the data analysis.
Reprints: Anne E. Sales, RN, MSN, PhD, Faculty of Nursing, University of Alberta, 3-114 Clinical Sciences Building, Edmonton, AB T6G 2G3, Canada. E-mail: firstname.lastname@example.org.