833 IS BMI ASSOCIATED WITH STONE FORMATION IN CHILDREN? SINGLE CENTER, PROSPECTIVE ANALYSIS

Abstract

INTRODUCTION AND OBJECTIVES: Multiple reports exist identifying an increasing epidemic of pediatric urolithiasis in the modern era. Causative factors have been postulated, such as the obesity and fast food epidemics. We hypothesize that BMI is not truly causative, but more likely a confounding factor, in pediatric stone formers. METHODS: A two-year prospective clinical trial enrolled 52 patients through the Pediatric Urology department at the Childreni s Hospital of Pittsburgh. Patient demographics, BMI, method of stone diagnosis, stone analysis, 24 hour urine studies, labs and spot urine studies, and treatments were catalogued. Logistic regression analysis was used to compare variables among stone forming children iU age 18. RESULTS: Data on BMI was available for 49 of 52 stone forming children. Imaging data was available in 46 of 49 patients, including confirmation by CT in 40 (87%), ultrasound in 3 (6.5%), and KUB in 3 (6.5%). The median age of presenting children was 15 (mean: 14.4 2.5), median stone burden 2.8mm (mean: 3.5 1.7) and median BMI 20.0 (mean: 20.4 4.2). Approximately 10% (5/49) children were overweight (BMI 25-30) and only 2% (1/49) were obese. Infected stones were present in 2 children (4.3%), and end stage renal failure in 1 (2.2%). Litholink® studies were completed on all 49 patients; 24hr urine electrolytes are as outlined in Table 1. No patients had cystinuria. CONCLUSIONS: mong pediatric stone formers, we did not find higher rates of obesity than compared with the local population. In fact, all overweight children forming stones in our cohort accounted for only 10% of total patients. Both normal and overweight children had low citrate levels by Litholink assay, although overweight children had a more substantial reduction in urinary citrate. Greater patient numbers are needed to determine the true effect of obesity on 24 hour urine parameters, and the reversible causes for increased stone formation, including dietary analysis.