Discrepancies in creatinine clearance in centenarians when calculated by two different mathematical formulas

Extract

Discrepancies in creatinine clearance in centenarians when calculated by two different mathematical formulas

Sir,

It is widely accepted that the glomerular filtration rate (GFR) and the renal blood flow decrease with aging. On the other hand, even after a significant fall in the GFR, the plasma level of creatinine may be normal in elderly patients due to a simultaneous decline in muscle mass. For the estimation of renal function (GFR), the Cockcroft–Gault formula (CG) is routinely used [1]. However, nowadays there are growing doubts about its accuracy, especially in individuals with normal or near normal renal function [2,3]. Recently, Baracskay et al. [4] presented a new formula (CB) for the elderly (CB=1/2[100/PCr]+88−age).

We calculated the creatinine clearance according to both formulas mentioned above in 81 centenarian subjects (71 females and 10 males). The mean age of studied subjects was 101.7±1.7 years (range 100–111 years: females, 101.8±1.9 years; males, 101.8±1.0 years). The study is part of the Polish Centenarians Program (co‐ordinated by the International Institute of Molecular and Cell Biology in Warsaw), that was developed to assess the environmental and genetic factors associated with aging in Poland. The study was based on a questionnaire, physical examination and hematological blood tests. This study included only four subjects with a small increase in plasma creatinine: one male, 1.57 mg/dl (normal values for males, 0.7–1.5 mg/dl) and three females with plasma creatinine between 2.03 and 2.12 mg/dl (normal values for females, 0.6–1.3 mg/dl). All other studied subjects had plasma creatinine within the normal range.