Kidney Week

Abstract: PO0392

Urine Phosphate Excretion and Microvascular Function in a Population-Based Cohort

Session Information

• Calcified Tissues in Kidney Diseases
  October 22, 2020 | Location: On-Demand
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Ginsberg, Charles, University of California San Diego, La Jolla, California, United States

Charles Ginsberg,

• Houben, Alfons Jhm, Universiteit Maastricht, Maastricht, Limburg, Netherlands

Alfons Jhm Houben,

• Malhotra, Rakesh, University of California San Diego, La Jolla, California, United States

Rakesh Malhotra,

• Berendschot, Tos, Universiteit Maastricht, Maastricht, Limburg, Netherlands

Tos Berendschot,

• Kooman, Jeroen, Universiteit Maastricht, Maastricht, Limburg, Netherlands

Jeroen Kooman,

• Webers, Carroll A.b., Universiteit Maastricht, Maastricht, Limburg, Netherlands

Carroll A.b. Webers,

• Stehouwer, Coen, Universiteit Maastricht, Maastricht, Limburg, Netherlands

Coen Stehouwer,

• Ix, Joachim H., University of California San Diego, La Jolla, California, United States

Joachim H. Ix,

Background

Higher serum phosphate is associated with cardiovascular events and all-cause mortality. While these associations have largely been attributed to an increased risk of large vessel calcification, our previous work demonstrated a higher morning serum phosphate is associated with microvascular dysfunction. However, the relationship between 24-hour urinary phosphate excretion ([(UPE) a surrogate for dietary phosphate] and microvascular function has not been explored.

Methods

We performed a cross-sectional analysis of 3,116 community-living participants that underwent a 24-hour urine collection and skin capillaroscopy, laser-Doppler flowmetry, and flicker-light induced retinal vessel responses as part of the Maastricht Study. The primary outcome was post-occlusive finger skin capillary recruitment. Secondary outcomes included capillary recruitment during venous congestion, heat-induced skin hyperemic response, and flicker-light induced retinal arteriolar and venular dilation.

Results

The mean age of the cohort was 60 years, 48% were women, 7% had an eGFR< 60ml/min/1.73 m², and the mean serum phosphate concentration was 3.2mg/dl. The mean UPE was 874 ± 315 mg/day. UPE was not associated with any of the microvascular outcomes (Table 1) and there were no significant interactions between UPE and sex, diabetes status or eGFR on any of the outcomes (P>0.43). We found an inverse relationship between UPE and serum phosphate (r=-0.26, p<0.001)

Conclusion

We found no relationship between UPE and microvascular function in community-living individuals predominantly with normal kidney function. Relationships between urine phosphate, serum phosphate and microvascular function require further exploration.

Funding

• NIDDK Support