Nurse staffing and patient outcomes.

OBJECTIVE: This study described the relationship between 6 adverse patient outcomes (medication errors, patient falls, urinary and respiratory tract infections, skin breakdown, patient complaints, and mortality), total hours of nursing care, and the proportion of those hours of care delivered by registered nurses (RNs).
METHODS: With use of hospital records, data from every unit of a large university hospital for fiscal year 1993 were analyzed. Correlations among staffing variables and outcome measures were determined, and multivariate analyses were completed, controlling for patient acuity.
RESULTS: Units with patients who had higher acuity had lower rates of medication errors and falls and higher rates of the other adverse outcomes. When patient acuity was controlled, an inverse relationship between RN hours of care and rates of medication errors, decubiti, and patient complaints was found. A direct relationship existed between total hours of care from all nursing personnel and rates of decubiti, complaints, and mortality. Interestingly, as the RN proportion of care rose to an 87.5% level, it related to a lower incidence of negative outcomes; however, when the RN proportion of care went beyond that level, the adverse outcome rates also increased.