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Abstract: FR-PO574

The Use of Urine Biomarker-Creatinine Ratio as the Exposure in Epidemiological Studies Alters the Exposure-Outcome Relationships

Session Information

Category: Fluid‚ Electrolyte‚ and Acid-Base Disorders

  • 1002 Fluid‚ Electrolyte‚ and Acid-Base Disorders: Clinical

Authors

  • Naser, Abu Mohd, Division of Epidemiology, Biostatistics, and Environmental Health, University of Memphis, Memphis, Tennessee, United States
  • Rahman, Md Mahbubur, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
  • Jahan, Farjana, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
  • Sumida, Keiichi, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
  • Shrestha, Prabin, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
  • Mallisetty, Yamini, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
  • Paul, Shejuti, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
  • Rhee, Connie, University of California Irvine, Irvine, California, United States
  • Kalantar-Zadeh, Kamyar, University of California Irvine, Irvine, California, United States
  • Kovesdy, Csaba P., The University of Tennessee Health Science Center, Memphis, Tennessee, United States
Background

The use of urine biomarker-creatinine ratio as exposure is common in epidemiological studies taht allows adjusting for the dilutional status of the urine under the assumption that individuals excrete same daily amount of creatinine. However, urine creatinine excretion varies based on an individual’s muscle mass, gender, age, and ethnicity. Hence, the use of urine biomarker-creatinine ratio may lead to measurement error. Regression adjustment for creatinine could be a better strategy to assess effects of urine biomarkers. Our aim was to compare the association of urine sodium concentration with blood pressure, proteinuria, and calciuria, using urine sodium-creatinine ratio (UNaCrR) vs. urine sodium adjusted (UNaCrAdj) for urine creatinine as exposures.

Methods

We used 10,050 person-visits pooled data from the coastal Bangladeshi population whose urine sodium, creatinine, total protein, calcium concentrations, and blood pressure were measured We created restricted cubic spline plots to visualize the relationship between UNaCrR and UNaCrAdj with three health outcomes, using linear mixed models (blood pressure) or quantile mixed models (for proteinuria and calcium).

Results

For UNaCrR, we found a U-shaped relationship with SBP and DBP; an upward and then plateaued relationship with urine protein and calcium concentrations. For UNaCrAdj, we found an inverse U-shaped relationship with SBP and DBP; and an upward positive relationship with urine protein and calcium concentrations (Figure).

Conclusion

We find altered relationships for UNaCrR versus UNaCrAdj with three outcomes. The plots for UNaCrAdj are more aligned with the published literature on the relationship of urine sodium with proteinuria and calciuria.

Funding

  • Private Foundation Support