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High Sodium Diet and Hypercalciuria In Children with Dysuria and/or Hematuria

Monday, October 22, 2012: 9:54 AM
Grand Ballroom B (Hilton Riverside)
Ruiyang Jiang1, Elizabeth Brown2, Karen Pritzker1, Anjana Shah1, Janelle Traylor1, Katherine Twombley2 and Nicol Corbin Bush, M.D.3, (1)Pediatric Urology, Children's Medical Center Dallas, Dallas, TX, (2)Pediatric Nephrology, Children's Medical Center Dallas, Dallas, TX, (3)Pediatric Urology, Children's Medical Center, Dallas, TX

Purpose

Hypercalciuria has been reported to cause dysuria, abdominal/flank pain, enuresis, and hematuria. Presumed to occur in 4-10% of the general pediatric population, a prior study demonstrated hypercalciuria on spot urine testing in 20-30% of patients referred for dysfunctional voiding (Parekh et al. JUrol 164:1008). Urinary calcium excretion is affected by sodium intake, and high sodium diet is common among US children >1 year of age. We hypothesized that high sodium diet could contribute to urinary symptoms, and so we evaluated the prevalence of hypercalciuria and the relationship of urinary calcium and sodium among patients referred to our dysfunctional voiding clinic.

Methods

Toilet-trained patients referred to our pediatric urology dysfunctional voiding clinic with dysuria and/or microscopic or gross hematuria had non-fasting spot urine testing of calcium, creatinine, and sodium on a random diet. Hypercalciuria was defined as spot urine calcium/creatinine ratio (Ca/Cr)>0.20mg/mg. Sodium excretion was measured with sodium/creatinine ratio (Na/Cr). Urine sodium excretion is the gold standard measure of sodium intake since dietary recall typically underestimates sodium intake. Analyses were performed with Spearman’s correlation, Chi-square test and Mann Whitney U.

Results

154 patients (53M:101F) with an average age of 8.26 years (SD 2.9) were evaluated with spot urine testing. 31 children (20%) had hypercalciuria. There was a significant positive correlation between urinary Ca/Cr and Na/Cr ratios, such that urinary calcium excretion increased with increasing sodium excretion (R=0.39, P<0.0001). Age and gender distribution were similar between those with and without hypercalciuria. In the highest Na/Cr quartile, 32.4% of patients were hypercalciuric compared to 2.6% in the lowest quartile. 

Conclusion

High sodium diet, measured by sodium excretion, contributes to hypercalciuria among patients with dysuria and/or hematuria. In addition to confirming that 20% of patients referred to pediatric urology have hypercalciuria on spot urine testing, we demonstrate there is a direct correlation with sodium excretion. Decreasing dietary sodium, and thus sodium excretion, has been shown to decrease urine calcium. Longitudinal study will demonstrate whether this simple diet maneuver can improve urinary symptoms in the subset of dysfunctional voiders with hypercalciuria.