Impact of Intensivist and Nursing Staff on Critically Ill Patient Mortality: A Retrospective Analysis of the Korean NHIS Cohort Data, 2011-2015

Abstract

Purpose: Critical care medicine continues to evolve. However, critical care cases require increasing amount of medical resources. Intensive care unit (ICU) mortality significantly impacts the overall efficiency of healthcare resources within a system of limitedmedical resources. This study investigated the factors related to ICU mortality using long-term nationwide cohort data in SouthKorea. Materials and Methods: This retrospective cohort study used data of 14905721 patients who submitted reimbursement claims tothe Korean Health Insurance Service between January 1, 2011 and December 31, 2015. A total of 1498102 patients who were admittedto all ICU types, except neonatal and long-term acute care hospitals, were enrolled. Results: Of the total 1498102 participants, 861397 (57.5%) were male and 636705 (42.5%) were female. The mean age at admissionwas 63.4±18.2 years; most of the subjects were aged over 60 years. During the 5-year period, in-hospital mortality rate was 12.9%. In Cox analysis, both in-hospital and 28-day mortality rates were significantly higher in male patients and those of lower socioeconomicstatus. As age increased and the number of nursing staff decreased, the mortality risk increased significantly by two or threetimes. The mortality risk was lower in patients admitted to an ICU of a tertiary university hospital and an ICU where intensivistsworked. Conclusion: The number of nursing staff and the presence of an intensivist in ICU were associated with the ICU mortality rate. Also, increasing the number of nursing staff and the presence of intensivist might reduce the mortality rate among ICU patients.