Association between Nurse Staffing and In-Hospital Bone Fractures: A Retrospective Cohort Study.

OBJECTIVE: To determine if sufficient nurse staffing reduced in-hospital fractures in acute care hospitals.

DATA SOURCES/STUDY SETTING: The Japanese Diagnosis Procedure Combination inpatient (DPC) database from July 2010 to March 2014 linked with the Surveys for Medical Institutions.

STUDY DESIGN: We conducted a retrospective cohort study to examine the association of inpatient nurse-to-occupied bed ratio (NBR) with in-hospital fractures. Multivariable logistic regression with generalized estimating equations was performed, adjusting for patient characteristics and hospital characteristics.

DATA COLLECTION/EXTRACTION METHODS: We identified 770,373 patients aged 50 years or older who underwent planned major surgery for some forms of cancer or cardiovascular diseases. We used ICD-10 codes and postoperative procedure codes to identify patients with in-hospital fractures. Hospital characteristics were obtained from the "Survey of Medical Institutions and Hospital Report" and "Annual Report for Functions of Medical Institutions."

PRINCIPAL FINDINGS: Overall, 662 (0.09 percent) in-hospital fractures were identified. Logistic regression analysis showed that the proportion of in-hospital fractures in the group with the highest NBR was significantly lower than that in the group with the lowest NBR (adjusted odd ratios, 0.67; 95 percent confidence interval, 0.44-0.99; p = .048).

CONCLUSIONS: Sufficient nurse staffing may be important to reduce postsurgical in-hospital fractures in acute care hospitals.