Abstract: FR-OR077

FGF23 Trajectories Among Patients Undergoing Chronic Hemodialysis in the HEMO Study

Session Information

Category: Mineral Disease

  • 1202 Mineral Disease: Vitamin D, PTH, FGF-23

Authors

  • Jovanovich, Anna Jeanette, Denver VA / University of Colorado, Denver, Colorado, United States
  • You, Zhiying, UC Denver, Aurora, Colorado, United States
  • Nowak, Kristen L., University of Colorado Denver: Anschutz Medical Campus, Aurora, Colorado, United States
  • Cervantes, Lilia, Denver Health, Denver, Colorado, United States
  • Isakova, Tamara, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
  • Wolf, Myles S., Duke University, Durham, North Carolina, United States
  • Chonchol, Michel, University of Colorado, Aurora, Colorado, United States
  • Kendrick, Jessica B., University of Colorado Denver and Denver Health Medical Center, Denver, Colorado, United States
Background

Single measurements of elevated circulating levels of fibroblast growth factor 23 (FGF23) are associated with all-cause mortality in patients with end stage kidney disease (ESKD); however, long-term patterns in FGF23 levels have been poorly characterized. The objective of this study was to identify common FGF23 trajectories in patients with ESKD, and to evaluate predictors and outcomes among trajectories.

Methods

The HEMO Study was a randomized multicenter study evaluating the effects of high-dose versus standard-dose and high-flux versus low-flux hemodialysis. Serum intact FGF23 (iFGF23) levels were measured in stored serum samples obtained at baseline and annually in this cohort. Among 919 HEMO participants with at least two measurements of iFGF23, latent mixture modeling was used to identify trajectories of iFGF23 over time. Logistics regression models were employed to identify demographics, cardiovascular risk factors, markers of mineral metabolism and other variables associated with trajectory group membership. Cox regression models were used to examine the association between trajectory group and all-cause mortality.

Results

We identified 5 distinct FGF23 trajectories during the initial 2 years of the HEMO study: low-stable (16.8%; n=154), moderate-increasing (17.3%; n=159), elevated-increasing (27.5%; n=253); elevated-stable (25.4%; 233) and moderate-decreasing (13.1%; n=120).
The only predictors of the moderate decreasing trajectory versus the low-stable trajectory were lower serum calcium (OR: 0.50; 95% CI 0.35-0.71; p <0.0001), lower serum phosphorus (OR: 0.64; 95% CI 0.53-0.78; p=0.0001), and lower serum interleukin-6 (0.58; 95% CI 0.39-0.87; p=0.009). In fully adjusted analyses, participants with elevated-stable FGF23 trajectory were at higher risk of death (HR: 1.61 95% CI 1.10-2.40; p=0.01) compared with the low-stable group trajectory.

Conclusion

FGF23 trajectories in patients undergoing hemodialysis vary and higher FGF23 trajectories are associated with an increased risk of death. Lower serum calcium and interleukin-6 appear to be important predictors of decreasing FGF23 levels.

Funding

  • NIDDK Support