Abstract: FR-PO1168
Sex-Specific Differences in Serum Phosphate Persist in Patients with CKD
Session Information
- CKD: Screening, Diagnosis, Serum and Urine Biomarkers, and Scoring Indices
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2301 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention
Authors
- Schatz, Martina, The University of Edinburgh Medical School, Edinburgh, Scotland, United Kingdom
- Tavares, Rafael Cruz Santana, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil
- dos Reis, Luciene, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil
- Elias, Rosilene M., Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil
- Moyses, Rosa M.A., Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil
Background
Phosphate (P) plays a critical role in numerous metabolic processes, and its serum levels have been linked to various clinical outcomes. Recent studies have identified sex-specific differences in serum P concentrations in the general population (GP) and propose revisiting the concept of phosphotoxicity according to sex. However, such differences have not been investigated in the context of CKD, where additional factors may have a more pronounced impact on serum P levels.
Methods
This retrospective study was conducted in an outpatient Nephrology clinic and included clinical and laboratory data from 632 patients (507 women) with CKD stages 1–5.
Results
The median age of the cohort was 51 years (IQR: 39–62), and the median serum P level was 3.5 mg/dL (IQR: 3.0–4.0). Serum P was negatively associated with age (r = –0.08; p = 0.04) and eGFR (r = –0.23; p < 0.001). Women had significantly higher serum P levels than men [3.6 mg/dL (IQR: 3.1–4.0) vs. 3.3 mg/dL (IQR: 2.9–3.9); p = 0.01]. No significant sex differences were observed in serum calcium, parathyroid hormone (PTH), 25vitamin D levels, or the use of vitamin D supplements, calcium salts, or calcitriol. In multivariate regression analysis adjusted for serum calcium, 25vitamin D, PTH, and ethnicity, serum P was independently associated with eGFR, age, and sex.
Conclusion
Our findings confirm that, even in the presence of CKD, women have higher serum P levels than men. This sex difference should be considered in the management of CKD-MBD. Furthermore, whether women with CKD experience fewer cardiovascular adverse effects from elevated P compared to men warrants further investigation.