Marked Increase in Number of US Patients With Kidney Stones Interview with:
Li Hao Richie Xu MD

Division of Mineral Metabolism
University of Texas Southwestern Medical Center
Dallas, Texas, United States What is the background for this study? What are the main findings?

Response: Over the past three decades, the prevalence of the kidney stones has escalated in the United States. Changes in dietary patterns, increasing body weight and obesity likely contributed to this significantly higher prevalence of kidney stone. In this study, we explored temporal changes in stone composition, demographic characteristics, and in serum and urinary kidney stone risk profile in kidney stone forming population for the last 35 years.

The proportion of uric acid stones has been almost doubled during this period. Although age and body mass index (BMI) increased over time in both uric acid and calcium stone formers, uric acid stone formers were consistently older, had higher BMI, and lower urinary pH than calcium stone formers. In addition, over time, the proportion of female vs. male increased in calcium stone formers, but not in uric acid stone formers. The most significant urinary parameter differentiating uric acid stone formers from calcium stone formers is 24-hour urinary pH. What should readers take away from your report?
 Response:  Three principal findings of this study include:

  • rising trend in proportion of uric acid stone formers associated with increased BMI and low urinary pH,
  • growth in proportion of female calcium stone formers, a
  • nd low urinary pH is the strongest clinical discriminant of uric acid stone occurrence.We would recommend that physicians send kidney stones for analysis of stone composition on a routine basis, and to consider collecting 24-hour urine, including for measurement of urine pH as this is a key discriminant, and in anticipation for preventive treatment based on stone type. What recommendations do you have for future research as a result of this study?

Response: Although gender influences excretion of the key urinary parameters related to the kidney stone formation, the underlying cause for the rising prevalence in calcium stones in women over time has not yet been fully elucidated.

Metabolic balance studies using fixed metabolic diet separating the effect of dietary indiscretion from obesity alone may shed light into underlying mechanism(s) of uric acid and calcium stone formation.

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Temporal Changes in Kidney Stone Composition and in Risk Factors Predisposing to Stone Formation
Xu, Li Hao Richie et al
The Journal of Urology , Volume 0 , Issue 0
Published online:January 19, 2017

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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