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Abstract: TH-PO181

The Effect of Intensive Blood Pressure Lowering on Markers of Mineral Metabolism in Persons with CKD in SPRINT

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Ginsberg, Charles, UCSD, San Diego, California, United States
  • Katz, Ronit, University of Washington, Seattle, Washington, United States
  • Chonchol, Michel, University of Colorado, Aurora, Colorado, United States
  • Bullen, Alexander, UCSD, San Diego, California, United States
  • Zhang, William R., UCSF School of Medicine, San Francisco, California, United States
  • Shlipak, Michael, San Francisco VA Medical Center, San Francisco, California, United States
  • Ix, Joachim H., UCSD, San Diego, California, United States
Background

Serum fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) concentrations are high in chronic kidney disease (CKD) and have been associated with increased cardiovascular disease (CVD) risk. The SPRINT trial demonstrated that intensive blood pressure (BP) lowering reduced risk of CVD despite more rapid eGFR decline. The effects of intensive blood pressure lowering on serum FGF23 and PTH are currently unknown.

Methods

Among individuals with CKD (eGFR < 60ml/min/1.73m2), we randomly selected 1000 participants and measured serum intact FGF23 (iFGF23; Kainos ELISA), intact PTH (iPTH), calcium, phosphate, and urine phosphate/creatinine at baseline and year 1. Thirteen were missing serum samples, resulting in 987 for analysis. We used linear mixed models to assess the effect of intensive BP lowering on iFGF23 and iPTH, in addition to changes in serum calcium, phosphate and fractional excretion of phosphate (FePhos).

Results

Mean age was 72±9 years, 42% were female, and mean eGFR was 46±10 ml/min/1.73m2. Demographics, baseline BP, kidney function, iFGF23, and iPTH were well-balanced across arms. Randomization to the intensive arm resulted in an increase in iFGF23 over 1 year compared with the standard BP arm (p=0.01) but no change in PTH [-1.6% (95% CI -6.1, 2.9]. After adjustment for 1 year changes in eGFR and albuminuria, persons in the intensive arm experienced an 11.2% (95% CI 6.2, 17.5) increase in serum iFGF23 compared with the standard arm. Randomization to the intensive arm did not impact calcium and phosphate or FePhos

Conclusion

In SPRINT participants with CKD, compared with the standard arm, randomization to the intensive BP arm led to an increase in iFGF23 that was independent of changes in eGFR. Future studies should determine whether increasing iFGF23 in persons receiving intensive BP therapy impacts CVD risk.

Funding

  • NIDDK Support