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Abstract: FR-PO170

Serum Phosphate and Microvascular Function in a Population-Based Cohort: The Maastricht Study

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Ginsberg, Charles, UCSD, San Diego, California, United States
  • Houben, Alfons Jhm, Maastricht University, Maastricht, Netherlands
  • Malhotra, Rakesh, UCSD, San Diego, California, United States
  • Berendschot, Tos, Maastricht University, Maastricht, Netherlands
  • Kooman, Jeroen, Maastricht University, Maastricht, Netherlands
  • Webers, Carroll A.b., University Eye Clinic Maastricht, Maastricht, Netherlands
  • Stehouwer, Coen, Maastricht University, Maastricht, Netherlands
  • Ix, Joachim H., UCSD, San Diego, California, United States
Background

Higher serum phosphate is associated with cardiovascular events and all-cause mortality. Explanations of this association have focused on large vessel-calcification and stiffness. Studies suggest that higher serum phosphate induces microvascular dysfunction, but relationships in humans with direct measures of microvascular function are lacking.

Methods

We performed a cross-sectional analysis of 3,189 community-living participants that underwent skin capillaroscopy, laser-Doppler flowmetry, or flicker-light induced retinal vessel responses. The primary outcome was capillary recruitment during post-occlusive peak reactive hyperemia by capillaroscopy. Secondary outcomes included capillary recruitment during venous congestion, heat-induced skin hyperemic response, flicker-light induced retinal arteriolar and venular dilation.

Results

The mean age of the cohort was 59 years, 48% were women, 7% had an eGFR< 60ml/min/1.73 m2, and the mean serum phosphate concentration was 3.2±0.5 mg/dl. A 1 mg/dl higher serum phosphate was independently associated with a 5.0% lower post-occlusive capillary recruitment (95%CI -10.0%,-0.1%). Results were similar for capillary recruitment with venous congestion (Table). A 1 mg/dl higher serum phosphate was also independently associated with a 0.23% lower retinal venular dilation in response to flicker-light (95%CI -0.44%,-0.02%). A higher serum phosphate was not associated with change in flicker-light induced retinal arteriolar dilation or heat-induced skin hyperemic response, however a higher serum phosphate was associated with a lower heat-induced skin hyperemic response among men (-149% 95%CI -260,-38, per 1 mg/dl higher serum phosphate).

Conclusion

Higher serum phosphate concentrations are associated with microvascular dysfunction in community-living individuals.

Adjusted Association of Phosphate with Microvascular Measurements
Measurement TechniquePer 1 mg/dl higher PhosphateP
% Capillary Recruitment during Post-Occlusive Reactive Hyperemia-5.0(-10.0, -0.1)0.04
% Capillary Recruitment during Venous Congestion-4.5(-9.8, 0.7)0.09
% Heat-Induced Skin Hyperemic Response- 25(-113, 63)0.57
% Retinal Arteriolar Dilation-0.12(0.3, 0.15)0.39
% Retinal Venular Dilation-0.23(-0.44, -0.02)0.03

Adjusted for age, sex, smoking, systolic blood pressure, anti-hypertensives, lipid medications, glucose metabolism, eGFR and serum calcium

Funding

  • NIDDK Support