Guessing Glomerular Filtration: A Systematic Review of the Validity of EGFR Calculations

JULS Volume 10, Issue 1

Sri Gaveen1,2, Nishant Fozdar2,3, Yanhong Li2

1 Faculty of Arts and Science, University of Toronto, Toronto, Canada
2 Department of Multi-Organ Transplant, University Health Network, Toronto, Canada
3 Faculty of Medicine, University of Toronto, Toronto, Canada

Corresponding Author: Sri Gaveen (iliyanag@uhnresearch.ca)

Abstract

Glomerular Filtration is the fundamental and most frequently employed assay of renal function, quantifying the unit volume of filtration occurring per unit time. Though precise and direct assays of the glomerular filtration rate (GFR) exist, such as inulin or other radiological tests, they are grossly impractical to perform in a typical clinical context, thus equations which estimate GFR are employed using naturally occurring biological markers like creatinine. This reviews sought to identify the best among the variety of equations (namely the Cockroft-Gault, the MDRD, the CKD-EPI and the Mayo Clinic equations) which most closely predicted a patient’s true GFR. Despite exhaustive revision of the published literature, a clear ‘best’ equation is indeterminable. Instead it is evident that equations typically perform best in populations mimicking the samples from which they were derived. Further, customized equations tend to perform ideally for their specific population, but may produce wildly inaccurate estimates elsewhere. This review demonstrates that for diverse, multi-ethnic populations, an effort should be made to determine which equation best estimates GFR in that specific population as no equation hitherto formulated is a panacea.