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

To determine the associations between insulin resistance, fibroblast growth factor 23 (FGF-23), and coronary artery calcification (CAC) in chronic kidney disease (CKD) patients.

FGF-23 is associated with atherosclerosis and cardiovascular disease, but its association with insulin resistance in CKD has not been explored.

Cross sectional study of 72 stage 3-5 CKD patients receiving care in Ontario, Canada.

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.

Median HOMA-IR was 2.19μU/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).

Insulin resistant CKD patients demonstrated higher FGF-23 levels, and increased CAC, while PO4 levels remained normal, suggesting a potential link between insulin resistance and PO4 homeostasis in CKD.