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Abstract: PO0539

Association of Combined Urinary Fractional Excretion of Phosphate and Serum FGF-23 with Adverse Events in Moderate and Advanced CKD: An Analysis from the CRIC Study

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Mendonça, Luís Carlos, Centro Hospitalar Universitario de Sao Joao, Porto, Porto, Portugal
  • Bigotte Vieira, Miguel, Nephrology Department, Hospital Curry Cabral, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
  • Neves, João Sérgio, Centro Hospitalar Universitario de Sao Joao, Porto, Porto, Portugal
Background

High levels of FGF23 are associated with adverse events in CKD. The urinary fractional excretion of phosphate (FePi) might modify this association, although data are limited in moderate and advanced CKD. We investigated the association of combined FePi and serum FGF23 with mortality, renal and cardiovascular events in patients with prevalent CKD 2-4.

Methods

Patients from the Chronic Renal Insufficiency Cohort (CRIC) were divided into four groups according to the median of FePi and FGF23: 1) low-FePi/low-FGF23, reference group; 2) high-FePi/low-FGF23; 3) low-FePi/high-FGF23; 4) high-FePi/high-FGF23. Primary outcomes were: incident heart failure; a composite atherosclerotic cardiovascular disease (ASCVD) outcome of myocardial infarction, ischemic stroke or peripheral artery disease; CKD progression; and all-cause mortality. The association of groups with the longitudinal outcomes was assessed through unadjusted and adjusted Cox proportional hazards models.

Results

We analyzed 3684 patients with a mean age of 58±11 years, 45% were male, and 42% were Black. Baseline mean eGFR was 44.3 ± 14.9 ml/min/1.73 m2. Median FePi and FGF23 were 26.5% (IQR, 19.5-36.8) and 145 (IQR, 95.6-238.3) RU/ml, respectively. The median time of follow-up was 12 (IQR, 7-13) years. The total number of events was 796 for incident heart failure, 717 for composite ASCVD, 1233 for CKD progression and 1328 for all-cause mortality. The adjusted relative risk of incident heart failure was higher in the low-FePi/high-FGF23 group (HR, 1.31; 95%CI, 1.03 to 1.67) and higher in the high-FePi/high-FGF23 group (HR, 1.58; 95%CI, 1.23 to 2.02), comparing to the low-FePi/low-FGF23 group. Composite ASCVD was higher in the high-FePi/high-FGF23 group (HR, 1.42; 95%CI, 1.11 to 1.80), but not in the low-FePi/high-FGF23 group (HR, 1.25; 95%CI, 0.98 to 1.59). All-cause mortality was higher in the low-FePi/high-FGF23 group (HR, 1.56; 95%CI, 1.30 to 1.89) and higher in the high-FePi/high-FGF23 group (HR, 1.57; 95%CI, 1.29 to 1.90). The adjusted risk of CKD progression was not different between groups.

Conclusion

In contrast to previous reports in patients with mild renal disease, the combination of high FePi and high FGF23 was associated with the highest risk of heart failure and ASVCD events in moderate and advanced CKD.