Objective To investigate the relationships of serum angiopoietin-like protein 4 (ANGPTL4) and fibroblast growth factor-23 (FGF-23) levels with the severity and prognosis of patients with diabetic nephropathy.

Methods A total of 120 patients (diabetic nephropathy group) with diabetic nephropathy were selected from July 2018 to July 2020 and divided into mild group (n=62) and severe group (n=58) according to the staging criteria of diabetic nephropathy; based on the prognosis within 3 years, they were also divided into good prognosis group (n=94) and poor prognosis group (n=26). Additionally, 102 diabetic patients were enrolled as diabetic group, and 81 healthy volunteers were selected as control group. The serum levels of ANGPTL4 and FGF-23 in diabetic nephropathy patients were detected by enzyme-linked immunosorbent assay (ELISA). Logistic regression analysis was used to analyze the influencing factors of prognosis, and receiver operating characteristic (ROC) curves were drawn to analyze the values of ANGPTL4, FGF-23 and their combination in assessing the severity and prognosis of diabetic nephropathy.

Results The levels of ANGPTL4 and FGF-23 in the diabetic nephropathy group and simple diabetic group were significantly higher than those in the control group (P < 0.05); compared with the simple diabetic group, the levels of ANGPTL4 and FGF-23 in the diabetic nephropathy group were significantly increased (P < 0.05); the levels of ANGPTL4 and FGF-23 in the severe group were significantly higher than those in the mild group (P < 0.05); the ROC curve analysis revealed that the areas under the curve (AUCs) for assessing disease severity of ANGPTL4, FGF-23 and their combination were 0.748, 0.781 and 0.858 respectively, and the combined diagnosis was significantly better than FGF-23 (Z=2.149, P=0.032) and ANGPTL4 (Z=2.886, P=0.004) alone; the levels of ANGPTL4 and FGF-23 in the good prognosis group were significantly lower than those in the poor prognosis group (P < 0.05); significant differences were observed in diabetes duration, blood urea nitrogen (BUN), serum creatinine (Scr), fasting blood glucose (FBG), glycated hemoglobin (HbA1C), hypertension, ANGPTL4 and FGF-23 levels between diabetic nephropathy patients with different prognoses (P < 0.05); the Scr, ANGPTL4 and FGF-23 levels were all risk factors affecting the prognosis of diabetic nephropathy (P < 0.05); the ROC curve analysis for prognosis assessment showed that the AUCs of ANGPTL4, FGF-23 and their combination were 0.774, 0.795 and 0.874 respectively; the combined diagnosis was significantly better than FGF-23 (Z=2.385, P=0.171) and ANGPTL4 (Z=2.317, P=0.021) alone.

Conclusion The serum levels of ANGPTL4 and FGF-23 are significantly increased in diabetic nephropathy patients, and they have certain reference value for the clinical diagnosis and prognosis assessment of diabetic nephropathy patients.