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Abstract: TH-PO182

Change in FGF23 and PTH1-84 and Subsequent Cardiovascular and Renal Events in Patients with Advanced CKD

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Canney, Mark, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
  • Djurdjev, Ognjenka, BC Renal Agency, Vancouver, British Columbia, 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, Stillwater, Minnesota, United States
  • Bonelli, Fabrizio, DiaSorin, Stillwater, Minnesota, United States
  • Levin, Adeera, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
Background

Elevated levels of parathyroid hormone (PTH1-84) and fibroblast growth factor 23 (FGF23), measured at a single time, are associated with increased risk of cardiovascular (CV) and renal events in patients with CKD. Few studies have examined the longitudinal association between bone mineral biomarkers (BMB) and outcomes. We sought to describe changes in PTH1-84 and FGF23 over time and their association with subsequent CV and renal events.

Methods

Using data from a prospective cohort of 1078 patients with advanced CKD in Canada under the care of nephrologists (2008-2013), we measured serial PTH1-84 and FGF23 (3 time-points) in a central laboratory using sensitive DiaSorin assays. Adjudicated CV (coronary artery disease, congestive heart failure, stroke, sudden cardiac death) and renal outcomes (initiation of renal replacement therapy (RRT)) were recorded over 3 years of follow-up after the last BMB measurement. We used group-based trajectory models to characterize patterns of change in BMB, and Cox regression models to relate these changes to CV and renal outcomes.

Results

Mean age was 69.9, 62% were male, 45% were diabetic and 45% had pre-existing CV disease. Mean eGFR was 27mL/min/1.73m2; 28%, 34% and 38% had eGFR <20, 20-29 & >30mL/min/1.73m2 respectively. We identified 3 distinct patterns of BMB change over time: low & stable (reference group), mid-level & stable, high & slowly rising. The proportions of patients in each category for PTH1-84 were 26%, 55% and 20% respectively. A small subgroup of patients (6%) had a high & rising pattern for FGF23. During median follow-up of 29 months, 11% experienced a CV event and 13% initiated RRT. Compared with the reference group, patients with mid-level & stable and high & rising patterns of each BMB had higher risk of CV events and RRT (Table). In multivariable models, only the high & rising patterns of PTH1-84 and FGF-23 demonstrated increased risk of CV events.

Conclusion

The majority of patients with advanced CKD had stable BMB values over time. A subgroup of patients had a high & rising pattern of change in PTH1-84 and FGF23 which conferred increased risk of CV events.

Funding

  • Commercial Support