The pros and cons of creatinine-based equations for estimating GFR in chronic kidney disease

Chronic kidney disease (CKD) is a growing clinical disorder manifested by structural and functional abnormalities, progressing to gradual kidney failure and end-stage renal disease (ESRD). CKD is characterized by decreased glomerular filtration rate, below 60 mL/min/1.73 m² that endure for over three months, and persistently increased albuminuria. Estimation of GFR is considered to be the most pertinent method for evaluating chronic kidney disease. Accurate assessment of GFR is therefore, essential for diagnosing and monitoring the progression of kidney disease. There have been several estimated glomerular filtration rate (eGFR) equations developed, and each one has unique properties. Clinical laboratories provide eGFR with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation or the Modification of Diet in Renal Disease (MDRD) study equation using serum creatinine according to the recommendation of the National Kidney Foundation (NKF) and American Society of Nephrology (ASN) Task Force. However, serum creatinine, is influenced by various factors including muscle mass, body weight, and gender. Since the impacts of the demographic factors, and extra-renal elimination, these equations may either underestimate or overestimate the true GFR and hence altered the clinical practice. To enable timely intervention and minimize the risk of complications, it is suggested to discover novel endogenous markers that can complement existing ones, thereby enhancing the accuracy of GFR estimation and facilitating early detection of CKD. This review highlights the need for further investigations across diverse population to improve the accuracy of GFR estimation.