Nurse-patient ratios: a systematic review on the effects of nurse staffing on patient, nurse employee, and hospital outcomes.

Objective: To determine whether the peer-reviewed literature supports specific, minimum nurse-patient ratios for acute care hospitals and whether nurse staffing is associated with patient, nurse employee, or hospital outcomes.

Background: Hospital care may be compromised by forces that have increased patient acuity, reduced the ratio of caregivers to patients, and lowered the level of training of these caregivers.

Methods: We systematically reviewed studies of the effects of nurse staffing on patient, nurse employee, and hospital outcomes published between 1980 and 2003 to determine whether they could guide the setting of minimum licensed nurse-patient ratios in acute care hospitals.

Results: Of 2897 titles and abstracts of interest, 490 articles were retrieved, and 43 met the inclusion criteria. Although all adjusted for case mix and skill mix, only one recent study addressed minimum nurse staffing ratios. Patient outcomes were limited to in-hospital, adverse events. Evidence suggests that richer nurse staffing is associated with lower failure-to-rescue rates, lower inpatient mortality rates, and shorter hospital stays.

Conclusion: The literature offers no support for specific, minimum nurse-patient ratios for acute care hospitals, especially in the absence of adjustments for skill and patient mix, although total nursing hours and skill mix do appear to affect some important patient outcomes.