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Kidney Week

Abstract: PO0471

Urinary Calcium Excretion and Risk of CKD Progression: The CRIC Study

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Liu, Jing, Renal Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States
  • Tio, Maria Clarissa, Renal Division, Brigham & Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Ilori, Titilayo O., Renal Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States
  • Verma, Ashish, Renal Division, Brigham & Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States
  • Schmidt, Insa Marie, Renal Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States
  • Waikar, Sushrut S., Renal Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States
Background

Hypercalciuria is implicated in nephrolithiasis and nephrocalcinosis, conditions associated with chronic kidney disease (CKD). We aimed to study the determinants of urinary calcium excretion (UCaE) and its association with adverse clinical outcomes in CKD.

Methods

24-hour UCaE was measured in 3,768 Chronic Renal Insufficiency Cohort (CRIC) participants. We used multivariable linear regression models to determine independent predictors of UCaE in CKD. Weighted Cox regression analyses tested the associations of UCaE with incident end stage kidney disease (ESKD), CKD progression (50% eGFR decline or incident ESKD), atherosclerotic cardiovascular disease (ASCVD) events, and death.

Results

Estimated glomerular filtration rate (eGFR) correlated most strongly with UCaE (r=0.417, P<0.001). In both males and females, determinants of UCaE included eGFR, African American race, iPTH, 24-hour urine sodium and phosphate, serum albumin and the use of diuretics and angiotensin receptor blockers (Figure 1). Certain predictors of UCaE differed between sexes: systolic blood pressure and alcohol drinker were associated with UCaE in males, while serum calcium and vitamin D intakes were significantly associated with UCaE in females. Higher UCaE was significantly associated with lower risk of ESKD, CKD progression, death and ASCVD events in unadjusted models. These associations were attenuated after adjusting for baseline characteristics, and for most outcomes the associations became insignificant after adjusting for eGFR.

Conclusion

Predictors of UCaE in CKD differed between males and females. eGFR is extremely strongly associated with UCaE and greatly confounds the associations between UCaE and all the outcomes.

β is from the linear model setting ln (UCaE) as dependent variable. UCaE Change= Exp(β)-1.