Abstract: FR-PO262

Ratios of Parathyroid Hormone, Fibroblast Growth Factor 23, and 1,25-Dihydroxylvitamin D and Cardiovascular Events

Session Information

Category: Mineral Disease

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

Authors

  • Levin, Adeera, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
  • Djurdjev, Ognjenka, BC Renal Agency, Vancouver, Alberta, Canada
  • Tang, Mila, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
  • Zierold, Claudia, DiaSorin, Stillwater, Minnesota, United States
  • Blocki, Frank A., DiaSorin INC, Stillwater, Minnesota, United States
  • Bonelli, Fabrizio, diasorin spa, Stillwater, Minnesota, United States
  • Wolf, Myles S., Duke University, Durham, North Carolina, United States
Background

Abnormal calcium homeostasis in patients with CKD may impact vascular health. Ratios of parathyroid hormone (PTH(1-84)), fibroblast growth factor 23 (FGF23) and 1,25-dihydroxylvitamin D (1,25(OH)2D) may provide insight into imbalances in the system and its relation to cardiovascular events (CVE).

Methods

We examined data from CanPREDDICT, a prospective CKD pan-Canadian cohort from 2008-2013, followed biannually for 5yrs, with adjudicated outcomes. PTH(1-84), intact FGF23 and 1,25(OH)2D were evaluated at baseline using precise new assays (Diasorin, Inc.). We used Cox proportional hazards to examine adjudicated CVE, adjusted for age, sex, diabetes and CVE history, BP, weight, eGFR, ACR, Alb, PO4, HCO3, Hgb, and ASA, ACEi, beta-blocker medications. Univariate and multivariate-adjusted HRs were calculated per 1 standard deviation increments using natural log-transformed variables where appropriate.

Results

The study cohort included 1789 pts with a median follow-up of 48 mo; mean age of 68yrs; 62% males; and mean eGFR of 28 ml/min/1.73m2 (19% < 20ml/min, 42% 20-29ml/min and 39% 30-45ml/min). 44% of patients had history of CV disease and 46% had diabetes. 339 (19%) patients experienced CVE. Higher FGF23 levels, and lower 1,25(OH)2D /FGF23 predicted significantly higher risk of CVE in unadjusted and adjusted analyses [p<0.01; Figure 1a] . The corresponding category-free net reclassification indices [95%CI] were 5%[-0.8 to 23.8%], and 7.7%[-6.4 to 20.2%] respectively.

Conclusion

High levels of FGF23 and lower 1,25(OH)2D/FGF23 predict higher risk of CVE. Further study of individual and combinations of biomarker levels is needed.