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Abstract: PO0592

Phosphate, Blood Pressure, and Endothelial Cell Dysfunction in a Population Study

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Van Buren, Peter N., The University of Texas Southwestern Medical Center Department of Internal Medicine, Dallas, Texas, United States
  • McAdams, Meredith C., The University of Texas Southwestern Medical Center Department of Internal Medicine, Dallas, Texas, United States
  • Xu, Pin, The University of Texas Southwestern Medical Center Department of Internal Medicine, Dallas, Texas, United States
  • Gregg, L Parker, Baylor College of Medicine, Houston, Texas, United States
  • Hedayati, Susan, The University of Texas Southwestern Medical Center Department of Internal Medicine, Dallas, Texas, United States
Background

Hyperphosphatemia contributes to medial vascular calcification in chronic kidney disease (CKD) patients. There is emerging evidence that phosphate (Ph) is also associated with microvascular disease in individuals with normal kidney function, with in vitro data supporting a toxic effect of Ph on endothelial cells. We hypothesized there would be an association between serum Ph, blood pressure (BP), and endothelial cell dysfunction (ECD) markers in a large, diverse cohort.

Methods

Using data from the Dallas Heart Study, a multi-ethnic population-based cohort, we used serum Ph as the predictor variable and conducted linear regression analysis to determine its association with systolic BP and serum asymmetric dimethylarginie (ADMA) from a single visit. We controlled for numerous demographic and clinical variables including parathyroid hormone (PTH), calcium, vitamin D, estimated glomerular filtration rate (eGFR), and albuminuria.

Results

There were 3301 participants with a mean age of 43 years. The median systolic BP was 122 [112, 134] mmHg. The eGFR was 102 [88, 114] mL/min. Serum calcium, Ph, PTH, and vitamin D levels were 9.2 [9, 9.5] mg/dL, 3.2 [2.8, 3.5] mg/dL, 37.3 [27, 51] pg/mL, and 17 [12, 23] ng/mL. Serum Ph and PTH were independently associated with both systolic BP and ADMA (Table 1), although there was a negative relationship between Ph and BP.

Conclusion

Even in the physiologic range, serum Ph and PTH were independently associated with higher ADMA, an ECD marker, in a diverse population while accounting for known predictors of hypertension including age, diabetes, and kidney function. Higher systolic BP was predicted by higher PTH, but lower Ph. The presence of these associations in individuals with preserved renal function warrant further studies in CKD, where hypertension and hyperphosphatemia are both more prevalent.

Multivariate Linear Regression Analysis
Predictor VariablesOutcomes
Systolic Blood Pressure (mmHg, reciprocal transformation)Serum Asymmetric Dimethylarginine (μmol/L, square root transformation)
βp-valueβp-value
Serum phosphate (mg/dL)6.1e-05.0490.0053.045
Age (years)-3.2e-05<.00010.001<.001
Serum parathyroid hormone (pg/mL)-2e-06.0020.0001.003
Serum vitamin D (ng/mL)8e-06<.001-0.0002.114
Serum calcium (mg/dL)-8.2e-05.1290.005.25

Model also controlling for race, sex, diabetes, serum albumin, estimated glomerular filtration rate, LDL cholesterol, urinary albumin to creatinine ratio

Funding

  • Veterans Affairs Support