Kidney Week

Abstract: SA-PO677

Prevention of Recurrent Stones and CKD in Kidney Stone Formers: What Are the Goals for Biochemical Parameters in Urine Collections?

Session Information

• Bone and Mineral Metabolism: Clinical - II
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Ramirez-Sandoval, Juan Carlos, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, México city, DISTRITO FEDERAL, Mexico

Juan Carlos Ramirez-Sandoval,

• Garcia-Sanchez, Cynthia, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, DIStrito federal, Mexico

Cynthia Garcia-Sanchez,

• Correa-Rotter, Ricardo, Institutor Nacional de la Nutricion, Mexico City, Mexico

Ricardo Correa-Rotter,

Background

The evidence of effective prevention of recurrent stone formation and CKD in kidney stone formers (KSF) through the treatment of biochemical abnormalities present in repeated 24h urine collections (24UC) is scarce. Our aim was to analyze the association between metabolic control (assessed by yearly 24UC) and kidney stone recurrence rates and decline in eGFR in KSF attending a nephrolithiasis clinic.

Methods

Single-center cohort study of KSF with at least three 24UC and ≥2 years of follow-up. Exclusions: primary hyperparathyroidism, eGFR >30 mL/min/1.73m². Medical data, including chemistry of 24UC, were compared using analysis of variance and general linear modelling.

Results

Of 220 KSF, 63% had absorptive hypercalciuria and 64% hipocitraturia (median follow-up of 4 yrs [IQR 4-5.2 yrs]). All KSF with hypercalciuria received chlortalidone. 24UC abnormalities display a trend to improve along time in all the cohort. Stone recurrence (≥2 episodes, 35% of KSF) was associated with higher urinary Ca/Cr index compared with KSF free of stone recurrence at follow up with treatment (yearly mean 24UC Ca/Cr 0.15±0.08 Vs. 0.12±0.05 respectively, p=0.02). Inappropriate eGFR decline (>2 mL/min/year) not related to obstruction or AKI episodes was observe in 13% of KSF and was associated with lower citraturia (yearly median citrate 192 mg/24UC [IQR 153-290] Vs 354 mg/24UC [IQR 237-541], p=0.003). Other parameters of the 24UC (volume recollected, Na, oxaluria, or uricosuria) were not associated with recurrence or eGFR decline.

Conclusion

Among 24UC yearly measurement; a very low Ca/Cr index was effective preventing stone recurrence in KSF. Low citrate excretion predicted an inappropriate eGFR decline, even before treatment.

Figure. Association between repeated urinary chemistry of yearly 24-hour collections and renal outcomes. A) Calciuria/creatinuria index and stone recurrence. B) Citrate excretion and eGFR Slope Decline.