Associations of fibroblast growth factor 23 with urate metabolism in patients with chronic kidney disease

Objective In patients with preserved kidney function, a positive association of fibroblast growth factor 23 (FGF23) with serum uric acid (SUA) has been reported; however, the relationship in overall chronic kidney disease (CKD) patients has not been investigated. No report has examined the relationship between FGF23 and uric acid clearance (CUA). The aim of the present study was to determine whether FGF23 is independently associated with urate metabolism in patients with CKD stages 1–5. Materials and methods In this cross-sectional study, 537 CKD patients were enrolled. SUA, CUA, FGF23, parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D (1,25(OH)₂D) were measured. Multivariable linear regression analysis was applied to determine independent factors associated with SUA or CUA. Results In all patients, both SUA and CUA were independently associated with male sex, use of diuretics, use of uric acid-lowering agents, estimated glomerular filtration rate, and log FGF23 (β = 0.29, P < 0.01 for SUA; β = − 0.11, P < 0.01 for CUA), but not with log PTH or log 1,25(OH)₂D. Dyslipidemia and diabetes were also independent factors for SUA and CUA, respectively. In multivariable analyses by sex, log FGF23 was associated with SUA in both sexes (β = 0.32, P < 0.01 in males vs. β = 0.20, P = 0.02 in females). Conversely, log FGF23 was independently associated with CUA in males (β = − 0.15, P < 0.01), but not in females (β = − 0.09, P = 0.17). Conclusions FGF23 was independently associated with urate metabolism in this population of CKD patients. FGF23 might also have a stronger association with urate metabolism in males compared with females.