MP03-07 URINARY STONE COMPOSITION IN THE UNITED STATES

Abstract

INTRODUCTION AND OBJECTIVE: There is a paucity of large-scale data on urinary stone composition in the United States. Here, we present characteristics of urinary stone composition, age and geographic region in the United States. METHODS: We obtained compositional analyses for all urinary stones submitted to a reference laboratory from July 15, 2016 to Sept. 29, 2019. Stone composition was determined by integrative crystallography. Stones containing >90 percent of particular chemicals were classified as purely made of that composition. Data was analyzed using Stata 16 (College Station, Texas) software. RESULTS: Total of 99,908 records of stones were analyzed. Of this 98,043 were categorized as urinary stones and remaining were non-crystalline physiological particulate matter or artifacts. Common stone types were calcium oxalate (79.33%), uric acid (10.63%), calcium phosphate (5.73%) and triple phosphate (2.22%). Rare variety of stones included predominantly protein (0.93%), cystine (0.26 %) and drug induced (0.22%). Incidence of calcium oxalate and uric acid stones increased with age and that of calcium phosphate decreased with age. Amongst patient with calcium oxalate stone, incidence of calcium oxalate monohydrate increased with age and that of mixed calcium oxalate stones and calcium oxalate dihydrate decreases with age (p<0.01) (figure 1 and 2). Although the incidence of common stone types was similar, overall association between stone composition and geographical distribution was found to be statistically significant (figure 3). CONCLUSIONS: This series is the largest analysis to date of urinary stone composition in the United States. Age and geographical region were significantly associated with variations in stone composition.Source of Funding: NIL