Evaluation of serum neutrophils gelatinase-associated lipocalin as a marker of diabetic nephropathy

Background. One of the most prevalent and serious microvascular complications of diabetes mellitus is diabetic nephropathy (DN). To optimize outcomes, it is crucial to identify DN early and accurately. Recently, tubulointerstitial indicators have gained attention as potential tools in the fight against diabetic kidney disease (DKD) in its early stages. One potential marker for renal function evaluation in diabetes mellitus cases is neutrophil gelatinase-associated lipocalin (NGAL). Objective. This study aims to evaluate the diagnostic effectiveness of serum neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker for the early detection of nephropathy in persons with both type 1 and type 2 diabetes mellitus. Methods. A case-control study was conducted at Faihaa Teaching Hospital (Faihaa Specialist Diabetes, Endocrine, and Metabolism Center) between January 2019 and December 2019. A total of 160 diabetic cases were categorized into three groups based on their urine albumin-to-creatinine ratio (ACR) levels: 61 with normoalbuminuria, 69 with microalbuminuria, and 40 with macroalbuminuria. The study also included 35 control subjects without diabetes. Every participant underwent a comprehensive medical assessment. Neutrophil gelatinase-associated lipocalin (NGAL), fasting serum glucose (FSG), urea, serum creatinine, serum albumin, and HbA1c levels were assessed. The urinary ACR and estimated glomerular filtration rate (eGFR) were computed. Results. Levels of serum NGAL were significantly elevated in diabetic cases compared to controls. Both macroalbuminuric and microalbuminuric cases exhibited significantly higher NGAL levels than normoalbuminuric cases. Out of 160 diabetic cases, 61 had normoalbuminuria, 69 had microalbuminuria, and 40 had macroalbuminuria, classified by their urine ACR ratios. The study also included 35 control subjects without diabetes. The ROC analysis revealed that a serum NGAL threshold of 223.06 ng/mL exhibited a sensitivity of 90.9%, specificity of 78.3%, and an area under the curve (AUC) of 0.938. Moreover, when predicting the presence of nephropathy, an ACR of 30.24 mg/g exhibited a sensitivity of 98%, specificity of 100%, and an AUC of 0.999. Conclusion. Diabetic patients, whether they have albuminuria or not, have substantially elevated serum neutrophil gelatinase-associated lipocalin, which suggests early tubular injury. Albuminuria is a strong predictor of nephropathy. NGAL testing has the potential to be a valuable technique for assessing diabetic renal involvement and detecting nephropathy at an early stage.