Category: Epidemiology, Health Policy, Socioeconomics & Outcomes
Introduction & Objective : Mechanisms of the formation for urinary stones are complex. Research have shown that there are differences within races and geologic regions. However, the potential effects of patient demographic factors on stone composition, especially age and sex, are not widely reported. As one of the biggest Stone Prevention and Management Centers in Northern China, we gathered the data of the past three years and presented our stone analysis results.
A retrospective study was performed among patients with urinary tract stones in our center. Data on urinary stone compositions were collected between December 2014 and December 2017 and analyzed. We used infrared spectroscopy for stone analysis, and recorded predominant stone component. Patients were divided into 9 age groups every ten years, and stones were classified in the following order: calcium oxalate, carbonate apatite, infection stone (struvite and ammonium urate), uric acid, calcium carbonate, apatite, brushite, cysteine, and other rare compositions.
Results : 978 men and 489 women were included with a male to female ratio of 2:1. Calcium oxalate (70.89%) was the most common, followed by infection stone (12.88%), uric acid (11.04%), carbonate apatite (3.14%), cysteine (0.95%), apatite(0.48%), calcium carbonate (0.2%), brushite (0.2%), and 2,8-dihydroxyadenine (0.2%). The top 3 stone compositions in men were calcium oxalate (74.64%), uric acid (12.68%) and infection stone (8.79%), while in women were calcium oxalate (63.39%), infection stone (21.06%), and uric acid (7.77%). Men submitted more calcium oxalate stones than women in the age of 30-49 years (p=0.005 for 30-39, and p＜0.001 for 40-49), and more uric acid stones in the age of 30-59 years (p=0.005 for 30-39, 0.029 for 40-49 and 0.006 for 50-59). Women submitted more infection stones than men between the ages of 30-69 years (p＜0.001, p＜0.001, p=0.007 and p＜0.001, respectively). Men had one peak of stone disease prevalence during the age of 40-49 years, while women had two peaks during the age of 30-39 years and 50-59 years. Both men and women had the lowest rate during the age of 10-19 years. Peak prevalence of uric acid stone was around 70 years and that of infection stone decreased with age in both men and women.
Conclusions : Age and gender have a great influence on the types of stone composition in Chinese population. Calcium oxalate is still the most common stone type. Men accounted for more calcium oxalate and uric acid stone submissions while women accounted for more infection stones. The second incidence peak in women may relate to the postmenopausal period.
University of Maryland School of Medicine
Shu Wang, M.D., is now a postdoc fellow in the Division of Urology, University of Maryland School of Medicine. Graduated from Peking University, he completed his resident training in Peking University People's Hospital and urological fellowship in Beijing Tsinghua Changgung Hospital. He performs a wide variety of surgical procedures such as URS, RIRS, PCNL, TUR and laparoscopy. Also he is actively engaged in a number of basic and clinical research projects related to the pathogenesis and prevention of stone formation and ultrasound guided PCNL techniques.