Kidney Week

Abstract: SA-PO757

Association of Tubular Solute Clearances with the Glomerular Filtration Rate and Complications of CKD: The CRIC Study

Session Information

• CKD: Mechanisms - III
  November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2103 CKD (Non-Dialysis): Mechanisms

Authors

• Chen, Yan, University of Washington, Seattle, Washington, United States

Yan Chen,

• Zelnick, Leila R., Kidney Research Institute, Seattle, Washington, United States

Leila R. Zelnick,

• Wang, Ke, University of Washington, Seattle, Washington, United States

Ke Wang,

• Katz, Ronit, University of Washington, Seattle, Washington, United States

Ronit Katz,

• Hsu, Chi-yuan, University of California San Francisco, San Francisco, California, United States

Chi-yuan Hsu,

• Go, Alan S., Kaiser Permanente Northern California, Oakland, California, United States

Alan S. Go,

• Feldman, Harold I., University of Pennsylvania, Philadelphia, Pennsylvania, United States

Harold I. Feldman,

• Mehta, Rupal, Northwestern Univesrsity, Feinberg School of Medicine, Chicago, Illinois, United States

Rupal Mehta,

• Lash, James P., University of Illinois at Chicago, Chicago, Illinois, United States

James P. Lash,

• Waikar, Sushrut S., Harvard Medical School, Boston, Massachusetts, United States

Sushrut S. Waikar,

• Hamm, L. Lee, Tulane University School of Medicine , New Orleans, Louisiana, United States

L. Lee Hamm,

• Chen, Jing, Tulane School of Medicine, New Orleans, Louisiana, United States

Jing Chen,

• Shafi, Tariq, University of Mississippi Medical Center, Jackson, Mississippi, United States

Tariq Shafi,

• Kestenbaum, Bryan R., University of Washington, Seattle, Washington, United States

Bryan R. Kestenbaum,

Background

The secretion of organic solutes by the proximal tubules is an essential intrinsic kidney function. However, the degree to which secretory solute clearance corresponds with the glomerular filtration rate (GFR) and potential implications of net secretory clearance are largely unknown.

Methods

We evaluated 1240 participants who underwent ¹²⁵I-iothalamate clearance (iGFR) measurements of GFR in the Chronic Renal Insufficiency Cohort (CRIC) Study. We used targeted mass-spectrometry to quantify 11 secretory solutes in 24-hour urine and plasma samples. We used correlation and linear regression to determine cross-sectional associations of secretory clearances with iGFR and common metabolic complications.

Results

Correlations between iGFR and secretory solute clearances ranged from ρ = 0.21 (p-cresol sulfate) to ρ = 0.55 (kynurenic acid). Lower clearances of most secretory solutes were associated with higher serum concentrations of parathyroid hormone (PTH), triglycerides, and uric acid (Figure). Each 50% lower kynurenic acid clearance was associated with a 16.1 pg/mL higher serum PTH concentration and an 18.2 mg/dL higher serum triglyceride concentration after adjustment for iGFR, albuminuria, and other potential confounders. Secretory solute clearances were not associated with meaningful differences in serum calcium, phosphate, hemoglobin, bicarbonate, or C-reactive protein concentrations.

Conclusion

Patients with CKD differ in their tubular secretory clearance for a given level of GFR. Lower net secretory clearances are associated with higher levels of PTH, triglycerides, and uric acid independent of GFR and albuminuria, suggesting potential clinical and biological relevance of this kidney function.

Figure. Adjusted associations of secretory solute clearances with PTH, triglyceride, and uric acid

Funding

• NIDDK Support