Relationship between serum FGF-23 and osteocalcin in patients with type 2 diabetes mellitus complicated with lower extremity arterial disease

Abstract

Objective To investigate the relationship between serum fibroblast growth factor-23 (FGF-23) and osteocalcin level in patients with type 2 diabetes mellitus (T2DM) complicated with lower extremity arterial disease (LEAD). Methods A total of 178 patients with T2DM admitted to the Department of Endocrinology in the First Affiliated Hospital of Harbin Medical University from November 2017 to May 2018 were selected. Atherosclerotic plaque in lower extremity was evaluated by color Doppler ultrasound. All patients were divided into simple diabetes mellitus group (n=98) and diabetes complicated with LEAD group (n=80) according to the status of LEAD. According to the severity of vascular disease, diabetes complicated with LEAD group were further divided into non-occlusion group (n=55) and occlusion group (n=25). The general data of all patients were collected, and the biochemical indicators including glycated hemoglobin, blood lipid, urea nitrogen, creatinine and fasting C peptide were measured. Serum FGF-23 and serum osteocalcin levels were measured by ELISA. Logistic regression analysis was used to investigate the risk factors of LEAD. Results Compared with simple diabetes group, age, blood urea nitrogen, creatinine, uric acid, cholesterol, triglyceride, fasting C peptide, and FGF-23 were increased (t=2.036-6.249, all P<0.01) in diabetes complicated with LEAD group. The positive rate of hypertension (χ2=11.193, P=0.001), neuropathy (χ2=10.382, P=0.001), drinking history(χ2=4.589, P=0.032), and abnormal carotid color ultrasound (χ2=33.386, P<0.001) were also higher but osteocalcin level was lower (χ2=4.189, P<0.001) in diabetes complicated with LEAD group. Compared with non-occlusion group, osteocalcin level was decreased (t=3.001, P<0.05), whereas FGF-23 level was elevated (t=2.233, P<0.05) in occlusion group. Logistic regression analysis found that age (OR=1.112, 95% CI: 1.041-1.188, P<0.05), drinking history (OR=3.415, 95% CI: 1.116-10.452, P<0.05), FGF-23 (OR=9.128, 95% CI: 3.610-23.080, P<0.05), osteocalcin (OR=0.369, 95% CI: 0.223-0.612, P<0.05) and carotid atherosclerosis (OR=4.801, 95% CI: 1.552-14.855, P<0.05) were independent influencing factors of LEAD. The level of FGF-23 was positively related with osteocalcin level in all patients diabetes as well as in diabetes complicated with LEAD group (r=0.327, 0.585, all P<0.001). Conclusions The level of serum osteocalcin is lower while the level of serum FGF-23 is higher in patients with T2DM and LEAD. Both osteocalcin and FGF-23 are associated with the severity of LEAD. Serum FGF-23 level is positively correlated with serum osteocalcin level in patients with T2DM and LEAD. Key words: Type 2 diabetes mellitus; Lower extremity arterial disease; Bone metabolism; Fibroblast growth factor-23; Osteocalcin