How Do Equations for Estimating Glomerular Filtration Rates Perform in Older Adults?

Laboratories use estimating equations when they report glomerular filtration rates (GFRs), but the accuracy of these equations in older adults has been questioned. In this cross-sectional, retrospective study, researchers in France identified 2250 patients (mean age, 72) who underwent inulin clearance testing (a reference standard for GFR measurement) from 2003 through 2017; insulin clearance results were compared with GFR estimates using four plasma creatinine–based equations: Chronic Kidney Disease–Epidemiology Collaboration (CKD-EPI; the most commonly used), Full Age Spectrum (FAS), Lund-Malmo Revised (LMR), and Berlin Initiative Study (BIS).

Mean GFR estimated by inulin clearance was ≈45 mL/minute/1.73 m². Each of the four equations prod…