Abstract: FR-PO0269
Urinary Sodium Excretion and Phosphate Homeostasis in Patients with CKD: The CRIC Study
Session Information
- Bone and Mineral Metabolism: Clinical Epidemiology and Outcomes
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 502 Bone and Mineral Metabolism: Clinical
Authors
- Kwon, Alvin Guyun, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- He, Jiang, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Geng, Siyi, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Richardson, Sydney L V, Tulane University, New Orleans, Louisiana, United States
- Wright, Layla H., Tulane University, New Orleans, Louisiana, United States
- Lanza, Paola, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- McAdams, Meredith C., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Lederer, Eleanor D., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Van Buren, Peter N., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Oygen, Suayp, Tulane University, New Orleans, Louisiana, United States
- Erol, Halil K., Tulane University, New Orleans, Louisiana, United States
- Gorrepati, Geetika, Tulane University, New Orleans, Louisiana, United States
- Batuman, Vecihi, Tulane University, New Orleans, Louisiana, United States
- Moe, Orson W., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Hamm, L. Lee, Tulane University, New Orleans, Louisiana, United States
- Chen, Jing, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
Group or Team Name
- CRIC Study Investigators.
Background
Phosphate retention is common in CKD and linked to higher mortality. Moderate sodium restriction may reduce phosphate excretion, likely due to lower intake, while high-salt diets increase urinary phosphate and intestinal absorption in mice. However, the impact of dietary sodium on phosphorus homeostasis in conditions with reduced sodium excretion, such as CKD, remains unclear. We examined associations between 24-hour urinary sodium excretion (a marker of intake) and serum phosphate related biomarkers in patients with CKD.
Methods
This analysis included 3,766 participants with CKD from the Chronic Renal Insufficiency Cohort (CRIC) Study after excluding those with missing data. Linear regression assessed cross-sectional associations of 24-hour urinary sodium with serum phosphate, calcium, fibroblast growth factor 23 (FGF23), alkaline phosphatase (ALP), and parathyroid hormone (PTH), adjusting for age, sex, black, center-sites, education, current smoker, calories/day, diabetes status, cardiovascular disease, body mass index, HbA1c, eGFR, use of ACE inhibitors, ARB, and vitamin D, and 24-hour urine creatinine.
Results
The average age of participants was 58 years, and the mean eGFR was 44 mL/min/1.73 m^2. After multiple adjustments, 24-hour urinary sodium excretion was significantly and positively associated with PTH and FGF23 (Table). However, urinary sodium excretion was not significantly associated with serum phosphorus, calcium, or ALP levels.
Conclusion
In patients with CKD, higher 24-hour urinary sodium excretion was associated with elevated PTH and FGF23 levels, independent of eGFR, diuretic use, and calorie intake. These findings suggest a potential causal link between high dietary sodium and increased PTH and FGF23, warranting further investigation.
Association of a One-SD (77 mmol/24 hours) Increase in 24-Hour Urinary Sodium Excretion with Significant Phosphate-Related Biomarkers
| Outcomes | Multivariable adjusted | |
| β Coefficient (95% CI) | P-value | |
| Log (PTH) (pg/mL) | 0.05 (0.02, 0.07) | < 0.001 |
| Log (FGF23) (RU/ml) | 0.04 (0.01, 0.06) | 0.01 |