Estimating GFR by serum creatinine, cystatin C, and β2-microglobulin in older adults: results from the Canadian Study of Longevity in Type 1 diabetes

Glomerular filtration rate (GFR) is a test used to determine how well the kidneys are working. It estimates how much blood passes through the glomeruli (tiny filters in the kidneys that remove waste from blood) every minute. However, the accuracy of GFR testing in older adults is uncertain. This study evaluated the accuracy of the standard GFR tests using the amount of creatinine in the blood, and GFR tests done with new methods using the protein cystatin C and the molecule β2-microglobulin. All participants in the study were older adults with longstanding type 1 diabetes or older adults without diabetes, none of whom had kidney disease. The study found that estimated GFR tested by these three methods was not a precise enough tool for measuring GFR in older adults without kidney disease. Better estimates of GFR in older adults are needed, as this subgroup of the population has an increased risk of developing chronic kidney disease and, because of this, testing requires greater accuracy.