Prognostic value of hematocrit levels among critically ill patients with acute kidney injury

Abstract

The aim of this study was to investigate the value of hematocrit (HCT) level in predicting the outcomes of critically ill patients with acute kidney injury (AKI). A retrospective study of a total of 14,350 intensive care unit (ICU) patients, who were selected from Beth Israel Deaconess Medical Center (Boston, MA, USA) and met the inclusion criteria, was carried out. And the patient data were extracted from the Multiparameter Intelligent Monitoring in Intensive Care Database III version 1.3 (MIMIC-III v1.3). In our study, HCT quintiles were used to categorize the subjects into groups. The clinical outcomes were 30- and 90-day mortality in the ICU. Cox proportional-hazards models were used to evaluate the association between the HCT and survival. A total of 2827 30-day deaths and 3828 90-day deaths occurred. In univariate analysis, low HCT was significantly associated with increased 30- and 90-day mortality among females, which, however, was not observed in multivariate analysis adjusted for age, ethnicity, dialysate, continuous renal replacement therapy (CRRT), use of insulin, use of ventilator, AKI stages, and report of obesity. In subgroup analysis, an inverse association between HCT levels and risk of mortality for 90-day outcome was observed for female patients by exclusion of dialysate use, receiving CRRT, and obesity reports. Therefore, these findings suggest that lower HCT was associated with an increased risk of mortality in critically ill patients with AKI, and the effect appears to be stronger among women than men. The prognostic value of HCT seems dependent on other factors, for example, dialysate use, CRRT, and obesity. Further multicenter study is in demand to confirm the validity of the results presented in this article.