(1325) ARCTIC Score & ARC Predictor to Identify Augmented Renal Clearance in Critically Ill Trauma Patients

Introduction: The goal of this study was to evaluate the accuracy and predictive ability of two scoring tools to identify augmented renal clearance (ARC) in critically ill trauma patients.

Methods: Patients ≥18 years of age, admitted to the trauma intensive care unit (TICU), referred to the Nutrition Support Service, and undergoing 24-hour urine collection for nitrogen balance (NBAL) and measured creatinine clearance (mCrCl) calculation were eligible for inclusion. Patients were divided into groups by presence or absence of ARC (mCrCl ≥130 mL/min/1.73m2). ARCTIC score ≥6 and ARC Predictor probability threshold >0.5 were considered positive predictions. Descriptive statistics were used for baseline demographics and clinical outcomes. The scoring tools were assessed by determination of sensitivity, specificity, positive (PPV) and negative (NPV) predictive values. Multivariable logistic regression analyses were conducted to determine the performance of the ARCTIC score (Model 1) and ARC Predictor (Model 2) in the presence of other risk factors for ARC.

Results: Two hundred patients were included; 122 (61%) patients had ARC (mCrCl 180 [158-219] mL/min /1.73m2) and 78 patients did not (mCrCl 105 [85-119] mL/min /1.73m2). Sensitivity and specificity for ARCTIC ≥6 were 88.5% and 53.8%, and for ARC Predictor >0.5 were 77.1% and 88.5%, respectively. PPV and NPV for ARCTIC ≥6 were 75.0%, and 75.0%, and for ARC Predictor >0.5 were 91.3%, and 71.1%, respectively. Each regression model included traumatic brain injury, Injury Severity Score, obesity, and NBAL. TBI increased the probability of ARC while obesity and higher NBAL decreased the odds in Models 1 and 2. ARCTIC ≥6 (OR 8.59 [95% CI 3.90-18.92]) and ARC Predictor >0.5 (OR 20.01 [95% CI 8.53-47.19]) remained the most significant predictors of developing ARC in each of their respective models.

Conclusions: The ARC Predictor had the best predictive value at a probability threshold >0.5, but the ARCTIC score ≥6 also performed well. Additional variables such as TBI may play a role in detecting the likelihood of ARC. The pragmatic nature of both the ARCTIC score and the ARC Predictor makes them appealing for use in the trauma population.