Insulin resistance is associated with Fibroblast Growth Factor-23 in stage 3-5 chronic kidney disease patients.

Abstract Aim To determine the associations between insulin resistance, fibroblast growth factor 23 (FGF-23), and coronary artery calcification (CAC) in chronic kidney disease (CKD) patients. Introduction FGF-23 is associated with atherosclerosis and cardiovascular disease, but its association with insulin resistance in CKD has not been explored. Subjects Cross sectional study of 72 stage 3–5 CKD patients receiving care in Ontario, Canada. Materials and Methods Insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR), FGF-23 was measured by carboxyl terminal enzyme linked immunoassay (ctFGF-23) and CAC was measured by multi-slice computed tomography. Results Median HOMA-IR was 2.19 μU/ml (interquartile range 1.19 to 3.94). Patients with HOMA-IR > 2.2 had greater ctFGF-23 (179.7 vs 109.6; P = 0.03), and 40% higher log CAC scores (2.09 ± 0.87 vs 1.58 ± 1.26; P = 0.049). Multivariable linear regression adjusted for 1,25 dihydroxyvitamin D, kidney function, and parathyroid hormone revealed insulin resistance was a risk factor for greater log ctFGF-23 levels (log HOMA IR β = 0.37; 95% confidence interval 0.14 to 0.59; P = 0.002). Conclusions Insulin resistant CKD patients demonstrated higher FGF-23 levels, and increased CAC, while PO 4 levels remained normal, suggesting a potential link between insulin resistance and PO 4 homeostasis in CKD.