The characteristics of the stone and urine composition in Chinese stone formers: primary report of a single-center results.
OBJECTIVE
To assess urine composition in Chinese patients with urolithiasis.


METHODS
Five hundred seven Chinese patients with urolithiasis from our center in southern China were included in this study. Analysis of stone composition was performed using infrared spectrometry. From all patients, 24-hour urine samples were collected for analysis of urinary variables. Some ion activity product risk indices were also calculated.


RESULTS
The major stone constituents in the 507 analyzed stones were as follows: calcium oxalate (78.3%), infection stone components (14.6%), uric acid (3.6%), and calcium phosphate (3.4%). Only 1 stone was composed of cystine (0.2%). Of all patients, 504 (99.4%) had 1 or several urinary metabolic abnormalities. Hypocitraturia was recorded in 93.9%, high sodium excretion in 58.6%, small urine volume in 45.6%, hyperoxaluria in 31.0%, hypercalciuria in 26.0%, hyperuricosuria in 19.3%, and hyperphosphaturia in 2.8%. Moreover, high sodium excretion was more frequent in men than women (59.2% vs 49.3%, P = .027), whereas hypercalciuria was more common in women (34.5% vs 20.4%, P <.001). High levels of urine sodium (187.7 ± 86.9 vs 179.8 ± 107.7 mmol/24h, P = .038) and phosphate (18.26 ± 8.36 vs 15.69 ± 11.14 mmol/24h, P <.001) were found in men than in women. Infection stones were significantly (P <.004) more common in women. Compared with noninfection stone formers, the occurrence of hypomagnesuria (P = .040) was more common in patients with infection stones.


CONCLUSIONS
The results of urinary risk factors for stone formation in this study might serve as a basis for design of recurrence prevention. It is of interest to note that some of the demonstrated abnormalities differ from that in reports from other countries.
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China. Electronic address: wwqwml@hotmail.com.
Wenqi
W
Wu
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China.
Dong
D
Yang
Division of Urology, Department of Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
Hans-Göran
HG
Tiselius
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China.
Lili
L
Ou
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China.
Yeping
Y
Liang
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China.
Hanliang
H
Zhu
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China.
Shujue
S
Li
Department of Urology, Minimally Invasive Surgery Center, the First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, China. Electronic address: gzgyzgh@vip.tom.com.
Guohua
G
Zeng
D000328:Adult; D002129:Calcium Oxalate / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D002681:China; D019343:Citric Acid / Q000652:urine; D003553:Cystine / Q000032:analysis; D005260:Female; D006801:Humans; D053565:Hypercalciuria / Q000652:urine; D006959:Hyperoxaluria / Q000652:urine; D008297:Male; D008875:Middle Aged; D019357:Potassium Citrate / Q000627:therapeutic use; D012015:Reference Standards; D012307:Risk Factors; D012737:Sex Factors; D012964:Sodium / Q000652:urine; D013055:Spectrophotometry, Infrared; D013997:Time Factors; D014527:Uric Acid / Q000032:analysis; D014545:Urinary Calculi / Q000737:chemistry*; D052878:Urolithiasis / Q000473:pathology* / Q000517:prevention & control / Q000652:urine*; D055815:Young Adult
D002130:Calcium Phosphates; D002129:Calcium Oxalate; D014527:Uric Acid; D019343:Citric Acid; D003553:Cystine; C020243:calcium phosphate; D012964:Sodium; D019357:Potassium Citrate