Usefulness of the neutrophil gelatinase-associated lipocalin/inflammation index ratio for assessing diabetic nephropathy in patients with type 2 diabetes

Kidney function and inflammatory conditions can affect plasma neutrophil gelatinase-associated lipocalin (NGAL) levels. This study aimed to investigate the usefulness of the NGAL-to-inflammation index ratio (NGAL/Inf ratio) for assessing diabetic nephropathy in patients with type 2 diabetes mellitus (T2DM). A total of 195 patients with T2DM were evaluated by measuring plasma NGAL levels, the NGAL/Inf ratio, urine albumin excretion (UAE), glycemic parameters, and inflammatory parameters. The concentration of plasma NGAL was significantly higher in patients with T2DM than in healthy individuals (130.5 ng/mL versus 71.0 ng/mL, P < 0.001). The NGAL/Inf ratio of patients with microalbuminuria was greater than that of patients with normoalbuminuria. UAE was more closely associated with the NGAL/Inf ratio than plasma NGAL. After adjusting for potential confounders, an elevated NGAL/Inf ratio was significantly associated with an increased risk for microalbuminuria (odds ratio = 1.34, 95% CI = 1.09-2.54, P = 0.012). In comparison with plasma NGAL (area under the curve = 0.599, 95% CI = 0.517-0.681), the NGAL/Inf ratio (area under the curve = 0.742, 95% CI = 0.671-0.814) demonstrated significantly better diagnostic efficacy for identifying microalbuminuria (P < 0.001). Moreover, the NGAL/Inf ratio significantly improved risk prediction for diabetic nephropathy compared with predictions made using the NGAL. In conclusion, the corrected plasma NGAL level (NGAL/Inf ratio) could provide more accurate information than the uncorrected plasma NGAL level for assessing diabetic nephropathy in patients with T2DM.