Comparison of 24‐hour urinary creatinine clearance and estimated glomerular filtration rate based on a panel of filtration markers in patients with chronic kidney disease

Abstract

Diagnosis and management of chronic kidney disease (CKD) requires accurate assessment of glomerular filtration rate (GFR). In practice, GFR is typically estimated by equations based on creatinine concentration in blood, but creatinine is affected by non‐GFR factors such as age and sex. Alternative filtration markers such as cystatin C, beta‐trace protein (BTP), and beta‐2 microglobulin (B2M) may be less dependent on age and sex, but equations combining these markers have not been investigated in patients with chronic kidney disease (CKD). In this cross‐sectional study of 50 patients with CKD stage 3–4, we compared kidney function estimates based on creatinine, cystatin C, BTP, B2M, or a combination of markers. Compared to the creatinine/cystatin C combination equation, the panel equation yielded a mean difference of only 2.8 ml/min/1.73 m2, indicating that switching to the panel equation would be unlikely to affect management.

Biomarkers of chronic kidney disease in older individuals: navigating complexity in diagnosis

“…Previous studies have shown that increased urinary and plasma BTP concentrations were highly correlated with serum levels of creatinine and cystatin C. Many studies have compared its diagnostic efficacy with conventional CKD biomarkers, such as creatinine, cystatin C and ACR, disclosing that increases in serum and urinary BTP levels correlate strongly with creatinine and cystatin C ( 79–81 ). Although BTP has a lower accuracy in eGFR estimation than cystatin C ( 73 , 82–85 ), it appears to be less influenced by race ( 86 ) and its assessment has been suggested particularly in cases where creatinine does not provide accurate results (e.g., in the creatinine-blind range) ( 85 , 87 ); in this context, lower serum BTP has been recently associated with slower GFR decline in older patients with normoalbuminuric CKD and diabetes ( 74 ). BTP was also associated with ACR and may be an early indicator of diabetic kidney disease (DKD); CKD patients with type 2 diabetes and microalbuminuria were found to have higher serum and urinary BTP levels than patients with normalbuminuria ( 88 ); furthermore, eGFR BTP improved prediction of CKD progression to ESKD and mortality compared to traditional eGFR measurements ( 66 , 67 ).…”