Augmented Renal Clearance in Chinese Intensive Care Unit Patients After Traumatic Brain Injury: Identifying Estimate Glomerular Filtration Rate Cut-off Value as a Risk Factor

Abstract

BackgroundAugmented renal clearance (ARC) is common in trauma patients and associated with subtherapeutic antimicrobial concentrations. China has more patients with traumatic brain injury (TBI) than most other countries in the world. However, there were no studies that focus on the ARC in Chinese TBI patients. In this study, we report the incidence of ARC in patients with TBI as well as risk factors for ARC. Besides, we evaluated the ability of four commonly used estimate glomerular filtration rate (eGFR) formulas and other covariates to predict the presence of ARC.MethodsThe prospective observational study was conducted in a 24-bed tertiary level, university-affiliated hospital, and 54 TBI patients with normal serum creatinine enrolled. We measured 24-h creatinine clearance after admission, and ARC defined as measured creatinine clearance ≥ 130 ml/min/1.73 m2. Demographic variables were then compared, and multivariate analysis was performed. Receiver operating curve, bias, and precision analyses were conducted to examine eGFR and ARCTIC score accuracy in predicting ARC. Multiple logistic regression analysis was performed to estimate the risk factors contributing to ARC. ResultsThe incidence of ARC was 50%. A moderate correlation was shown between measured Crcl and four eGFR (rs/r was 0.590, 0.499, 0.404, and 0.518, respectively). All of the equations significantly underestimated the measured Crcl, especially in the ARC group. Neither had excellent precision for clinical application in this setting. ARCTIC score can't accurately distinguish ARC either. Multivariable analysis displayed that four factors independently correlated to ARC: male, larger BMI, lower serum creatinine, and without a history of hypertension. Further investigation found eGFR higher than the threshold, without a history of hypertension, and/or bigger BMI were independent risk factors for ARC, and they had good accuracy in predicting the occurrence of ARC.ConclusionsARC was frequently observed in Chinese TBI patients. The estimated methods of GFR and ARCTIC score inaccurate and couldn't be directly used as a screening tool to identify ARC in Chinese TBI patients. But if we take the cut-off values of different formulas into account, the estimated GFR could be used as a decisive risk factor in helping to screen the ARC.