Predicting augmented renal clearance using estimated glomerular filtration rate in critically-ill children

Aims: Measured glomerular filtration rate (mGFR) is often used to identify augmented renal clearance (ARC). However, in the clinical setting, estimated GFR (eGFR) is obtained more quickly and inexpensively. We aimed to determine whether eGFR can identify ARC by evaluating the correlation between the eGFR and vancomycin trough level (VTL). Materials and methods: We retrospectively reviewed the records of patients aged ≤ 18 years who underwent vancomycin therapeutic drug monitoring at our tertiary hospital from July 2009 to June 2014. VTL, serum creatinine concentration, eGFR, and clinical factors affecting VTL were analyzed. Results: Of 101 patients, 76 (75.25%) had a subtherapeutic VTL. Patient age (p = 0.006), the daily vancomycin dose (p = 0.041) and dosing interval (p = 0.006), and eGFR (p < 0.001) affected the VTL. Multivariate analysis showed a significant relationship between eGFR and VTL (adjusted R², 0.812; p < 0.001). An increased eGFR (odds ratio, 1.002; 95% confidence interval, 1.001 - 1.003; p = 0.001) was a risk factor for a subtherapeutic vancomycin level. The cutoff eGFR value predicting a subtherapeutic vancomycin level was 110.51 mL/ min/1.73m² (area under the curve, 0.753). Conclusions: The eGFR correlates with the VTL, and the eGFR cutoff value can predict a subtherapeutic vancomycin level. eGFR is a reliable and efficient alternative to mGFR for identifying ARC.