Nurse staffing and patient care costs in acute inpatient nursing units.

OBJECTIVE: Studies suggest that a business case for improving nurse staffing can be made to increase registered nurse (RN) skill mix without changing total licensed nursing hours. It is unclear whether a business case for increasing RN skill mix can be justified equally among patients of varying health needs. This study evaluated whether nursing hours per patient day (HPPD) and skill mix are associated with higher inpatient care costs within acute medical/surgical inpatient units using data from the Veterans Health Administration. METHODS: Retrospective cross-sectional study, including 139,360 inpatient admissions to 292 acute medical/surgical units at 125 Veterans Health Administration medical centers between February and June 2003, was conducted. Dependent variables were inpatient costs per admission and costs per patient day. RESULTS: The average costs per surgical and medical admission were $18,624 and $6,636, respectively. Costs per admission were positively associated with total nursing HPPD among medical admissions ($164.49 per additional HPPD, P<0.001), but not among surgical admissions. Total nursing HPPD and RN skill mix were associated with higher costs per hospital day for both medical admissions ($79.02 per additional HPPD and $5.64 per 1% point increase in nursing skill mix, both P<0.001) and surgical admissions ($112.47 per additional HPPD and $13.31 per 1% point increase in nursing skill mix, both P<0.001). Patients experiencing complications or transferring to an intensive care unit had higher inpatient costs than other patients. CONCLUSIONS: The association of nurse staffing level with costs per admission differed for medical versus surgical admissions.