Brigham investigators looked at 1,783 inpatients and outpatients who had 24-hour cystatin C and creatinine levels drawn between January 1, 2018, and September 9, 2020. They evaluated how cystatin C eGFR correlates with creatinine eGFR aging.
They found that cystatin C-based eGFR was strongly correlated with creatinine-based eGFR, and that 27 percent of patients would be classified as having more severe chronic kidney disease based on cystatin C test results; Patients with borderline renal function between stages were more likely to change stage.
Cystatin C as a marker for GFR
The researchers also found that Black patients were less likely to be classified into a more severe stage than White patients, but there were limitations in self-reported race data. These results are important because Black, Hispanic, and Native American patients have been shown to have less frequent visits to nephrology, access to transplants, home dialysis treatment, and increased rates of progression to kidney failure.
“Nationally, attention must be paid to making this important test affordable and accessible to a wide, diverse patient population,” said Mallika Mendu, MD, chief physician of BWH’s Division of Nephrology, associate professor, and senior author of the study. .