Kidney Week

Abstract: TH-PO524

Sex Differences in Primary Distal Renal Tubular Acidosis

Session Information

• Genetic Kidney Diseases: Genotypes and Phenotypes in Cases
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1202 Genetic Diseases of the Kidneys: Non-Cystic

Authors

• D'Ambrosio, Viola, Universita Cattolica del Sacro Cuore, Rome, Italy

Viola D'Ambrosio, MD

• Siew, Keith, University College London, London, United Kingdom

Keith Siew, MS, MSc, PhD

• Evans, Rhys, University College London, London, United Kingdom

Rhys Evans, MA, MBBS, PhD

• Ferraro, Pietro Manuel, Universita degli Studi di Verona, Verona, Veneto, Italy

Pietro Manuel Ferraro, MD, MS, PhD

• Walsh, Stephen B., University College London, London, United Kingdom

Stephen B. Walsh, MD, MBBS, PhD

Group or Team Name

• London Tubular Center.

Background

The kidney is one of the most estrogen-responsive organs and an influence of estrogens has been described for several transporters along the renal tubule. Primary distal renal tubular acidosis (dRTA) are rare genetic conditions characterized by impaired urinary acidification in the collecting duct. Our study aimed to investigate phenotypic sex differences in the natural history of primary dRTA.

Methods

We studied 31 genetically confirmed dRTA patients followed at the London Tubular Centre. We undertook a retrospective analysis of prospectively collected clinical, biochemical and radiological data. We used low bone mineral density (BMD) (defined as a Z-score ≤ -2) to assess the severity of osteomalacia.

Results

Baseline characteristics and prevalence of causative mutations are shown in Figure 1. Most patients regardless of sex presented with overt hypercalciuria (60% of women vs 90% of men) but prevalence of nephrolithiasis and nephrocalcinosis was higher in women. Men had a significantly (p value=0.0138) higher decline in annual mean slope of eGFR ( -3.3 ± 2.5 mL/min/1.73 m²) compared to women ( -0.5 ± 1.5 mL/min/1.73 m²) (Figure 2a). There was a trend towards higher fractional excretion of phosphate (Figure2b) and dyslipidemia in men (Figure 2c). Prevalence of low BMD was higher in men (50%) vs women (17%) with low BMD predominantly affecting the lumbar spine.

Conclusion

Men affected by primary dRTA are at increased risk of CKD progression and appear to be more dyslipidemic than women. To our knowledge, this is the first study reporting sex differences in primary dRTA.