AB196. Multivariate analyses of urinary calculi composition: a 13-year single-center study

Background: The incidence and prevalence of urinary stone are increasing throughout the world. Compared with the past, urolithiasis compositions by patient demographics are strikingly different. Furthermore, recent clinical studies implied that seasonal cyclicity might influence the distribution of stone composition.

Methods: We sought to determine the trends in pathogenesis of urolithiasis based on urinary stone analyses. A total of 2,383 eligible urinary stone samples from different patients between 2002 and 2014 in our center were collected. Infrared spectroscopy was used for urinary calculi analysis. Logistic regression analysis was used to investigate the relationship of urinary calculi composition and calendar month (season), gender and age in North China during the past 13 years.

Results: Calcium containing calculi were the most frequent with an overall incidence of 84.1%. Calcium phosphate (CaP) or magnesium ammonium phosphate (MAP) stones were more frequent in females, while monohydrate calcium oxalate (COM), dihydrate calcium oxalate (COD) or uric acid (UA) stones were more common in males. Older individuals were associated with an increased risk of UA stones and a decreased risk of COD, CaP or cystine stones. Additionally, from 2002 to 2014, the frequency of COD and MAP stone increased, whereas the trend of CaP, UA and cystine stones decreased. However, calendar month (season) was not significantly associated with differences in composition.

Conclusions: This study provides a picture of the present distribution of urolithiasis compositions in China. From 2002 to 2014, age and gender were significantly associated with stone composition, whereas calendar month not.

Keywords: Urolithiasis; sex; age groups; China