Evidence of the Association between Nurse Staffing Levels and Patient and Nurses' Outcomes in Acute Care Hospitals across Japan: A Scoping Review.

We aimed to summarize the evidence of an association between nurse staffing and nursing sensitivity outcomes in Japanese hospitals. A scoping review was conducted and reported following the PRISMA-SR 2020 statement. The ICHUSHI and CiNii databases were searched for published articles written in Japanese and PubMed and CINAHL for those written in English. Out of the 15 included studies, all observational studies, 3 were written in Japanese and the others in English. The nurse staffing level measures were grouped into three categories: patient-to-nurse ratio, nursing hours per patient day, and nurse-to-bed ratio. The outcome measures were grouped into three categories: patient outcome, nursing care quality reported by nurses, and nurse outcome/nursing care quality. Some studies reported that the nursing staff increasingly favored positive patient outcome. Conversely, the findings regarding failure to rescue, in-hospital fracture, and post-operative complications were inconsistent. Although some studies indicated that more nurse staffing was favored toward better patient and nurse outcomes, due to the sparse accumulation of studies and heterogeneity among the findings, it is difficult to draw robust conclusions between nurse staffing level and outcomes in Japanese acute care hospitals.