Is Hospital Nurse Staffing Legislation in the Public's Interest?: An Observational Study in New York State

Abstract

Background: The Safe Staffing for Quality Care Act under consideration in the New York (NY) state assembly would require hospitals to staff enough nurses to safely care for patients. The impact of regulated minimum patient-to-nurse staffing ratios in acute care hospitals in NY is unknown. Objectives: To examine variation in patient-to-nurse staffing in NY hospitals and its association with adverse outcomes (ie, mortality and avoidable costs). Research Design: Cross-sectional data on nurse staffing in 116 acute care general hospitals in NY are linked with Medicare claims data. Subjects: A total of 417,861 Medicare medical and surgical patients. Measures: Patient-to-nurse staffing is the primary predictor variable. Outcomes include in-hospital mortality, length of stay, 30-day readmission, and estimated costs using Medicare-specific cost-to-charge ratios. Results: Hospital staffing ranged from 4.3 to 10.5 patients per nurse (P/N), and averaged 6.3 P/N. After adjusting for potential confounders each additional patient per nurse, for surgical and medical patients, respectively, was associated with higher odds of in-hospital mortality [odds ratio (OR)=1.13, P=0.0262; OR=1.13, P=0.0019], longer lengths of stay (incidence rate ratio=1.09, P=0.0008; incidence rate ratio=1.05, P=0.0023), and higher odds of 30-day readmission (OR=1.08, P=0.0002; OR=1.06, P=0.0003). Were hospitals staffed at the 4:1 P/N ratio proposed in the legislation, we conservatively estimated 4370 lives saved and $720 million saved over the 2-year study period in shorter lengths of stay and avoided readmissions. Conclusions: Patient-to-nurse staffing varies substantially across NY hospitals and higher ratios adversely affect patients. Our estimates of potential lives and costs saved substantially underestimate potential benefits of improved hospital nurse staffing.