Relationships between serum and urine phosphorus with all-cause and cardiovascular mortality: The osteoporotic fractures in men (MrOS) study

Julie R. Dominguez, Bryan Kestenbaum, Michel Chonchol, Geoffrey Block, Gail A. Laughlin, Cora E. Lewis, Ronit Katz, Elizabeth Barrett-Connor, Steve Cummings, Eric Orwoll, Joachim H. Ix

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28 Scopus citations

Abstract

Background: Serum phosphorus is associated with cardiovascular disease (CVD) in the general population, but may not comprehensively reflect phosphorus homeostasis. Whether urine phosphorus-creatinine ratio (a marker of intestinal absorption) or urine fractional excretion of phosphorus (FEPi; a marker of urinary phosphorus handling) is associated with risk of mortality or CVD is uncertain. Study Design: Prospective observational study. Setting & Participants: 1,325 community-dwelling men 65 years or older participating in the MrOS Study. Predictor: Serum phosphorus, urine phosphorus-creatinine ratio, and FEPi. Outcomes: All-cause and CVD death. Results: Mean age was 74 ± 6 (SD) years, estimated glomerular filtration rate was 75 ± 16 mL/min/1.73 m2, and serum phosphorus level was 3.2 ± 0.4 mg/dL. During a median follow-up of 9.3 years, there were 364 (120 CVD) deaths. After adjustment for demographics, CVD risk factors, and kidney function, the risks of all-cause death in the highest quartiles of serum phosphorus (≥3.6 mg/dL), urine phosphorus-creatinine ratio (≥0.55), and FEPi (≥18%) were 1.63 (95% CI, 1.23-2.17), 1.22 (95% CI, 0.90-1.65), and 0.88 (95% CI, 0.64-1.23), respectively, compared to the lowest quartiles of each. Results were similar for CVD death. Results also were similar in those with estimated glomerular filtration rate ≥60 and 2. Limitations: Older all-male cohort. Few had advanced chronic kidney disease. Spot urine specimens were used. Conclusions: In community-living older men, higher serum phosphorus concentrations are associated with all-cause and CVD death. In contrast, urine phosphorus-creatinine ratio and FEPi are not. These findings do not support using urine phosphorus-creatinine ratio or FEPi as adjuvant measures to predict risk of mortality or CVD in the general population.

Original languageEnglish (US)
Pages (from-to)555-563
Number of pages9
JournalAmerican Journal of Kidney Diseases
Volume61
Issue number4
DOIs
StatePublished - Apr 2013

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Keywords

  • cardiovascular disease
  • geriatrics
  • kidney disease
  • mortality
  • Phosphorus
  • urine phosphorus

ASJC Scopus subject areas

  • Nephrology

Cite this

Dominguez, J. R., Kestenbaum, B., Chonchol, M., Block, G., Laughlin, G. A., Lewis, C. E., Katz, R., Barrett-Connor, E., Cummings, S., Orwoll, E., & Ix, J. H. (2013). Relationships between serum and urine phosphorus with all-cause and cardiovascular mortality: The osteoporotic fractures in men (MrOS) study. American Journal of Kidney Diseases, 61(4), 555-563. https://doi.org/10.1053/j.ajkd.2012.11.033