Kidney Week

Abstract: FR-PO776

FGF23 Is Associated With Cardiovascular Functional Capacity Before and After Kidney Transplantation

Session Information

• Transplantation: Clinical - Biomarkers
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Halim, Arvin, Indiana University School of Medicine, Indianapolis, Indiana, United States

Arvin Halim,

• Burney, Heather, Indiana University School of Medicine, Indianapolis, Indiana, United States

Heather Burney,

• Li, Xiaochun, Indiana University School of Medicine, Indianapolis, Indiana, United States

Xiaochun Li,

• Li, Yang, Indiana University School of Medicine, Indianapolis, Indiana, United States

Yang Li,

• Lu, Tzongshi, Brigham and Women's Hospital, Boston, Massachusetts, United States

Tzongshi Lu,

• Hiemstra, Thomas, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

Thomas Hiemstra,

• Zehnder, Daniel, North Cumbria Integrated Care NHS Foundation Trust, Whitehaven, Cumbria, United Kingdom

Daniel Zehnder,

• Lim, Kenneth, Indiana University School of Medicine, Indianapolis, Indiana, United States

Kenneth Lim,

Background

Impaired cardiovascular functional capacity is a major complication in CKD and associated with mortality. Fibroblast Growth Factor 23 (FGF23) is a bone-derived phosphaturic hormone that is involved in cardiac remodelling in CKD. To-date, it is unknown whether FGF23 has a role in regulating cardiovascular functional capacity in CKD. Herein, we sought to examine the relationship between FGF23 and exercise ventilatory response variables of cardiovascular functional capacity.

Methods

We analyzed a total of 235 patients from the Cardiopulmonary Exercise Testing in Renal Failure and After Kidney Transplantation (CAPER) cohort: 87 advanced chronic kidney disease (CKD) stage 5 patients who underwent kidney transplantation, 65 non-transplanted waitlisted CKD patients, and 83 hypertensive controls. 186 patients were followed longitudinally for 1-year. All patients underwent cardiopulmonary exercise testing (CPET).

Results

Patients in higher FGF23 quartiles had significantly lower mean arterial pressure (p<0.001) and lower BMI (p=0.004) compared to patients with lower levels of FGF23. There was no significant difference in sex (p=0.5) or age (p=0.08) across quartiles. Patients with high FGF23 levels exhibited impaired VO₂Max (p<0.001) as well as VO₂AT (p<0.001), peak exercise heart rate (p<0.001), max workload (p<0.001), and endurance time (p<0.001) compared to patients with low FGF23 levels. There was no significant difference in oxygen pulse (p=0.2). Patients in all quartiles achieved a mean respiratory exchange ratio ≥1.0. Among patients who underwent kidney transplantation, FGF23 significantly decreased at 2 months post-transplant (p<0.001), followed by significant improvement in VO₂Max (p<0.001) and max workload (p<0.001) at 1-year. Multivariable regression modelling revealed significant association between FGF23 and VO₂Max before and after kidney transplantation after adjusting for age, sex, systolic blood pressure, smoking status, dyslipidemia, and albumin and hemoglobin levels.

Conclusion

FGF23 levels are inversely associated with cardiovascular functional capacity before and after kidney transplantation. Our study suggests that FGF23 may be a regulator of alterations in cardiovascular functional capacity in CKD.

Funding

• Other NIH Support