Vega Jorge, Huidobro E Juan Pablo, Sepúlveda Rodrigo Andrés
Servicio de Medicina Interna, Hospital Naval Almirante Nef, Viña del Mar, Chile.
Departamento de Nefrología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Rev Med Chil. 2021 Feb;149(2):187-195. doi: 10.4067/s0034-98872021000200187.
Glomerular filtration rate (GFR) estimation in older adults using a creatinine clearance/24-hour (CrCl) or an equation based on serum creatinine, are often considered equivalent by clinicians.
To compare GFR estimated (eGFR) with the available equations and measured CrCl in patients ≥ 70 years. A secondary aim was to know the differences in chronic kidney disease (CKD) classification, when using the different eGFR formulas.
In 144 patients aged 77 ± 5 years (58% men), CrCl was measured and GFR was estimated using MDRD, CKD-EPI, BIS-1 and FAS formulas. The eGFR and the stage of CKD were compared according to the different equations used.
GFR estimated by MDRD and CKD-EPI equations was 7.8 and 8.4 mL/min/1.73 m2 lower than 24-hour ClCr, respectively. This difference was even greater using the BIS-1 and FAS equations. Twenty-four-hour CrCl classified 47.2% of the patients in a category of renal function > 60 mL/min/1.73 m2, while MDRD and CKD-EPI equations classified just over a third, and BIS-1 and FAS formulas around 20% of the patients.
The practice of considering equivalent the GFR estimation using the creatinine-based equations with measured creatinine clearance in older adults should be reconsidered, because their results differ markedly.
