Early Detection of Diabetic Nephropathy Based on Urinary and Serum Biomarkers: An Updated Systematic Review

Diabetic nephropathy (DN) is a leading cause of chronic kidney disease (CKD) and end-stage renal disease worldwide, particularly among individuals with type 2 diabetes mellitus (T2DM). Early detection and intervention are crucial in slowing the progression of DN and improving patient outcomes. Traditional diagnostic methods, such as the measurement of albuminuria and serum creatinine, often fail to detect early renal damage because structural kidney damage may occur before albumin excretion. This systematic review aims to evaluate the diagnostic value of various urinary and serum biomarkers in the early detection of DN in patients with T2DM. A comprehensive literature search was conducted using databases such as PubMed, Scopus, and Web of Science. We only considered studies involving human populations for inclusion in our analysis. Animal and in vitro studies were excluded from our review. Our analysis of 17 observational studies identified several key serum biomarkers, such as netrin-1, osteopontin, adiponectin, and specific cytokines (e.g., IL-6, IL-8), which show significant promise for early detection of DN. Urinary biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), transferrin, N-acetyl-β-D-glucosaminidase (NAG), and various cytokines, have also proven to be reliable indicators. The combination of both serum and urinary biomarkers may enhance diagnostic accuracy and enable earlier intervention. Additionally, incorporating genetic and mRNA markers could provide a more comprehensive approach to early DN detection. Implementing these biomarkers in clinical practice could significantly improve outcomes for patients with DN by facilitating early diagnosis and timely management.