Kidney Week

Abstract: TH-OR021

FGF23 and Falls in SPRINT

Session Information

• CKD-MBD: Phosphorus, FGF-23, and Trials
  October 25, 2018 | Location: 33C, San Diego Convention Center
  Abstract Time: 04:30 PM - 04:42 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Jovanovich, Anna Jeanette, Denver VA , Denver, Colorado, United States

Anna Jeanette Jovanovich, MD

• Ginsberg, Charles, UCSD, San Diego, California, United States

Charles Ginsberg,

• You, Zhiying, UC Denver, Aurora, Colorado, United States

Zhiying You,

• Cheung, Alfred K., University of Utah, Salt Lake City, Utah, United States

Alfred K. Cheung,

• Chonchol, Michel, University of Colorado, Aurora, Colorado, United States

Michel Chonchol,

• Shlipak, Michael, San Francisco VA Medical Center, San Francisco, California, United States

Michael Shlipak,

• Ix, Joachim H., UCSD, San Diego, California, United States

Joachim H. Ix,

Background

Fibroblast growth factor 23 (FGF23) is elevated in chronic kidney disease and associated with kidney disease progression and increased mortality. There are little data on circulating FGF23 levels and falls despite the fact that FGF23 is derived from bone and regulates phosphorus and 1,25-dihydroxyvitamin D. The purpose of this analysis was to evaluate the relationship between intact FGF23 (iFGF23) and falls in the Systolic Blood Pressure Interventional Trial (SPRINT).

Methods

SPRINT was a randomized multicenter trial evaluating the effects of standard (SBP <140 mmHg) vs. intensive (SBP <120 mmHg) blood pressure lowering on cardiovascular outcomes among older adults without diabetes. iFGF23 was measured among 2488 participants with eGFR < 60 mL/min/1.73m². Cox proportional hazards models adjusted for demographics, comorbidities, randomization group, baseline number of antihypertensives, eGFR, and serum calcium, phosphorus, and intact parathyroid hormone identified the relationship between baseline iFGF23 and time to first fall.

Results

Mean age was 73 ± 9 years, 40% were female, and 66% were white. Mean eGFR was 49 ± 11 mL/min/1.73m² and median iFGF23 was 66 [52-88] pg/mL. After full adjustment, participants with iFGF23 levels in the highest quartile (compared to the lowest) demonstrated >2-fold increased risk of falling (HR 2.00 [95% 1.20-2.67]), and a doubling of iFGF23 level was associated with an increased risk of fall (HR 2.34 [95% CI 1.28-4.28]). Intact FGF23 did not modify the relationship between randomization to intensive blood pressure lowering and fall (p for interaction 0.96).

Conclusion

Among SPRINT participants with baseline eGFR < 60 mL/min/1.73m², iFGF23 was significantly associated with increased risk of falls; however, FGF23 did not modify the relationship between randomization to intensive blood pressure lowering and falls. FGF23 has been associated with frailty in a large cohort of older community-dwelling adults. Our novel finding that FGF23 increases risk of fall supports a link between FGF23 and frailty. Further investigation is necessary.

Funding

• NIDDK Support