Red blood cell distribution width predicts gastrointestinal bleeding after coronary artery bypass grafting

Background Red blood cell distribution width (RDW) is highly associated with adverse clinical outcomes in many diseases. The present study aimed to evaluate the relationship between RDW and gastrointestinal bleeding (GIB) after isolated coronary artery bypass grafting (CABG). Methods This was a retrospective observational study that included 4473 patients who received CABG, and all the data were extracted from the Medical Information Mart for Intensive Care III database. Data collected included patient demographics, associated comorbid illnesses, laboratory parameters, and medications. The receiver operating characteristic (ROC) curve was used to determine the best cutoff value of RDW for the diagnosis of GIB. Multivariable logistic regression analysis was used to analyze the relationship between RDW and GIB. Results The incidence of GIB in patients receiving CABG was 1.1%. Quartile analyses showed a significant increase in GIB incidence at the fourth RDW quartile (> 14.3%; P < 0.001). The ROC curve analysis revealed that an RDW level > 14.1% measured on admission had 59.6% sensitivity and 69.4% specificity in predicting GIB after CABG. After adjustment for confounders, high RDW was still associated with an increased risk of GIB in patients with CABG (odds ratio = 2.83, 95% confidence interval 1.46-5.51, P = 0.002). Conclusions Our study indicates that the elevated RDW level is associated with an increased risk of GIB after CABG, and it can be an independent predictor of GIB. The introduction of RDW to study GIB enriches the diagnosis method of GIB and ensures the rapid and accurate diagnosis of GIB. Keywords: Red blood cell distribution width, Gastrointestinal bleeding, Coronary artery bypass grafting