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Kidney Week

Abstract: TH-PO411

Estimating Residual Kidney Function in Dialysis Patients Without Urine Collection

Session Information

Category: Dialysis

  • 703 Dialysis: Peritoneal Dialysis


  • Steubl, Dominik, Tufts Medical Center, Boston, United States
  • Fan, Li, Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University; Key Laboratory of Nephrology, Ministry of Health; Guangdong Provincial Key Laboratory of Nephrology, , Guangzhou, China
  • Inker, Lesley, Tufts Medical Center, Boston, Massachusetts, United States
  • Tighiouart, Hocine, Tufts Medical Center, Boston, Massachusetts, United States
  • Dekker, Friedo W., Leiden University Medical Center, Leiden, Netherlands
  • Karger, Amy B., University of Minnesota, Minneapolis, Minnesota, United States
  • Eckfeldt, John H., University of Minnesota Medical School, Minneapolis, Minnesota, United States
  • Zhang, Hao, The Third Xiangya Hospital of Central South University, Changsha, HUnan, China
  • Hu, Jing, The third Xiangya hospital of Central South Univercity, Changsha, China
  • Liao, Yunhua, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
  • Shafi, Tariq, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
  • Chen, Wei, The First Affiliated Hospital, Sun Yat-sen University,, Guangzhou, China
  • Yu, Xueqing, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
  • Levey, Andrew S., Tufts Medical Center, Boston, Massachusetts, United States

Measurement of RKF is recommended for adjustment of the dialysis prescription, but timed urine collections are difficult and prone to errors. Few equations to estimate RKF in dialysis patients using serum concentrations of low molecular weight proteins (LMWP) have been externally validated (Shafi T et al, Kidney Int 2016).


We developed RKF estimating equations using linear regression analysis in 823 peritoneal dialysis patients in the Guangzhou PD Study. The reference tests were measured clearance of urea nitrogen (UN) (mClUN, ml/min) and average clearance of UN and creatinine (mClUN-cr, ml/min/1.73 m2). The index tests were estimated clearance (eCl) using UN and creatinine (eClUN-cr), beta-trace-protein (eClBTP), beta-2-microglobulin (eClB2M), cystatin C (eClcys) and combinations. Equations were then externally validated in 826 hemo- and peritoneal dialysis patients in the NECOSAD study and also compared to published validated equations.


In external validation, bias was within ±1.0 (Table). Precision and accuracy were significantly better for eClBTP, eClB2M and eClBTP-B2M than eClUN-cr. The area-under-the-curve for predicting mClUN >2.0 ml/min for eClB2M and eClBTP-B2M was 0.853 and 0.848, respectively (Figure). Results were similar to other validated equations.


These results confirm the validity and extend the generalizability of estimation of RKF from serum concentrations of LMWPs without urine collection.


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