A new approach to urinary stone analysis acccording to the combination of the components: experience with 7,949 cases

Abstract

ObjectiveTo evaluate a new approach to urinary stone analysis based on the combination of their components. Materials and methodsWe analyzed a total of 7,949 stones and their main components and combinations of components and we classified them according to gender and age. We performed statistical analysis using the chi-square test. ResultsCalcium oxalate monohydrate (COM) was the most frequent component in both males (39%) and females (37.4%), followed by calcium oxalate dihydrate (COD) (28%) and uric acid (URI) (14.6%) in males and by phosphate (PHOS) (22.2%) and COD (19.6%) in females (p=0.0001). In young people, COD and PHOS were the most frequent components in males and females respectively (p=0.0001). In older patients, COM and URI (in that order) were the most frequent components in both genders (p=0.0001). COM is oxalatedependent and is related to diets with a high oxalate content and low water intake. The progressive increase in URI with age is related mainly to overweight and metabolic syndrome. Regarding the combinations of components, the most frequent were COM (26.3%), COD+Apatite (APA) (15.5%), URI (10%) and COM+COD (7.5%) (p=0.0001). ConclusionsThis study reports not only the composition of stones but also the main combinations of components according to age and gender. The results prove that stone composition is related to the changes in dietary habits and life-style that occur over a lifetime, and the morphological structure of stones is indicative of the etiopathogenic mechanisms.