Abstract

Purpose
Analysis of urinary stone composition is essential for treatment and prevention of urolithiasis. We evaluated the effect of age, gender, and stone location on urinary stone components during the last five years.
Materials and Methods: We conducted a retrospective analysis of the medical records of 375 patients ranging in age from 15 years old to 93 years old (241 males and 134 females) who underwent conventional or endoscopic surgery, shock wave lithotripsy, or passed their stones spontaneously between 2009 and 2013. Stone analysis was performed using a chemical analysis method to determine the molecular composition of each stone.
Results: Of the 375 patients with urolithiasis, 152 patients (40.5%) had predominantly calcium oxalate, 85 patients (21.5%) had uric acid, 17 patients (4.5%) had calcium phosphate, 17 patients (4.5%) had magnesium ammonium phosphate, 16 patients (4.3%) had calcium carbonate, and 86 patients (22.9%) had mixed stone type. There was a decreasing prevalence of calcium oxalate stone with age group (42.5% in young adult (20-39 years, n=40), 45.0% in adult (40-60 years, n=151), and 32.7% in elderly (≥60 years, n=180) as opposed to increasing prevalence in uric acid stone (7.5% in young adult, 15.2% in adult and 32.2% in elderly). Uric acid stones were more common in males and in lower urinary tract stones.
Conclusions: In this study, the incidence of calcium oxalate decreased with age and that of uric acid increased with age and in male. In comparison of the results of previous studies for several decades, the incidence of uric acid increased in the last five years.

• Keywords: Urinary calculi; Analysis; Uric acid