The utility of eGFR difference (eGFRCystatin C - eGFRCreatinine) in the diagnosis, prognosis, and management of chronic kidney disease: a comprehensive review.

INTRODUCTION: The estimated glomerular filtration rate (eGFR) calculated from serum creatinine has limitations in accurately reflecting kidney function due to its dependence on muscle mass and non-GFR determinants. The eGFR difference (eGFR diff = eGFR Cystatin C - eGFR Creatinine) has emerged as a novel biomarker that may provide additional clinical information beyond that provided by traditional eGFR measurements.

METHODOLOGY AND RESULTS: A comprehensive literature review of peer-reviewed studies investigating eGFR diff in CKD populations, focusing on diagnostic accuracy, prognostic value, and clinical applications was conducted. The eGFR diff reflects the differential effects of non-GFR determinants on creatinine and cystatin C. A positive eGFR diff (eGFRCys eGFRCr) is associated with reduced muscle mass, inflammation, and increased cardiovascular and mortality risks. Conversely, a negative eGFR diff may indicate preserved muscle mass or creatinine elevation due to non-GFR factors. Medical literature reveals that eGFR diff improves the risk prediction for CKD progression, cardiovascular events, and mortality beyond that of traditional risk factors. The eGFR diff is an invaluable clinical tool that enhances CKD risk stratification and provides insights into patient phenotypes beyond kidney function alone.

CONCLUSION: The integration of eGFR diff into clinical practice may improve personalized CKD management and clinical outcomes.