The Status and Characteristics of Urinary Stone Composition in China

Urolithiasis has become more prevalent throughout China.Knowing stone composition helps identify their possible underlying etiology of urolithiasis, provide appropriate individualized treatment and prevent stone recurrence.To explore characteristics of urinary stone composition in China, and determine the effects of gender, age, body mass index (BMI), stone localization and geographical region on stone composition.We used Fourier transform infrared spectroscopy to analyse urinary stones from consecutive patients at 46 hospitals in seven geographic areas of China between June 1, 2010 and May 31, 2015.Chi-squared tests and logistic regression analyses were performed to determine associations between stone composition and sex, age, body mass index (BMI), stone location, and geographic region.The most common stone components were calcium oxalate (CaOx; 65.9%), carbapatite (15.6%), urate (12.4%), struvite (2.7%), brushite (1.7%), and cystine (0.9%). CaOx and urate occurred more frequently in males, whereas carbapatite and struvite were more common in females (p<0.01). CaOx and carbapatite stones were more common in those 30-50 and 20-40 years old, respectively than in other groups. Brushite and struvite stones were most common among those younger than 20 and older than 70 years old. Urate stone incidence increased with age. Cystine stone incidence decreased with age. Obese patients were more likely to have urate stones than carbapatite or brushite stones (p<0.01). CaOx, carbapatite, brushite, and cystine stones were more frequently observed in the kidney than other types, whereas urate and struvite stones were more frequent in the bladder (p<0.01). Stone composition varied by geographic region.Stone composition differed significantly in patients grouped by gender, age, BMI, stone localization, and geographic region. Funding: Supported by Health industry special scientific research projects, ministry of health of China (No. 201002010). Declaration of Interest: All authors declare that they have no competing interests. Ethical Approval: The study protocol was approved by the Tongji Hospital, Huazhong University of Science and Technology Research Ethics Committee (reference number TJ2010-036), the research ethics committees of the individual participating institutions, and the corresponding regional health authorities in areas where the project was implemented. All procedures performed in studies were in accordance with the 1964 Helsinki Declaration and its later amendments ethical standards.All patients gave informed consent before participating.