Association between registered nurse staffing levels and in-hospital mortality in craniotomy patients using Korean National Health Insurance data

Background: The level of registered nurse (RN) staffing is a fundamental factor influencing patient safety. Craniotomy patients need intensive care after surgery, the majority of which is provided by RNs. Methods: This study was conducted to investigate the relationship of the RN staffing level of general wards and intensive care units (ICUs) with in-hospital mortality after craniotomy using Korean National Health Insurance claim data. The RN staffing level was categorized based on the bed-to-RN ratio. Results: The in-hospital mortality rate of craniotomy patients was elevated at hospitals with a high bed-to-RN ratio in general wards, ICUs, and hospitals overall. It was determined that in-hospital mortality of craniotomy patients could be decreased by more than 50% by reducing the bed-to-RN ratio from 4.5 or more to less than 3.5 in general wards, from 1.25 or more to less than 0.88 in ICUs, and from 2.5 or more to less than 1.67 in hospitals overall. Conclusions: Since the RN staffing level is related to the in-hospital mortality rate of craniotomy patients, a sufficient staffing level of RNs should be ensured to reduce the mortality of craniotomy patients.