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2301 INFLUENCE OF OBESITY ON 24-HOUR URINE CHEMISTRY STUDIES & RECURRENT UROLITHIASIS IN CHILDREN
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THE JOURNAL OF UROLOGY姞
CONCLUSIONS: Incidence of nephrolithiasis is high postRYGB at a rate of 12.5%. This risk is mitigated in a dose-dependent manner by vitamin D supplementation, and is optimized at 1000IU. Prospective trials are needed to explore the role that vitamin D may play in reducing nephrolithiasis.
Source of Funding: None
2300 CHANGING STONE COMPOSITION PROFILE OF CHILDREN WITH NEPHROLITHIASIS Kyle Wood*, Irina Stanasel, Ross Holmes, Steve Hodges, Patrick Mufarrij, Gordon McLorie, Dean Assimos, Winston-Salem, NC INTRODUCTION AND OBJECTIVES: An increasing number of adult patients with nephrolithiasis have calcium phosphate stones. This is further accentuated in those who are recurrent stone formers. We performed a retrospective study to determine if similar trends are present in children. METHODS: We reviewed records of 179 patients managed from 1992-2010 (0.2 to 18 year olds) for whom stone analysis data were available. Demographic and metabolic data were reviewed. A comparison of patients managed from 1992-2000 (period 1 – P1) and 2001-2010 (period 2 – P2) was undertaken. Statistical analysis included non-parametric Chi-square and Student’s t-Test. RESULTS: The overall average age of manifestation did not differ between the periods (10.6 years in P1 and 11.1 years in P2). Mean age of males was 9.2 for P1 and 10.1 for P2. Mean age for females was 12.0 for P1 and 12.1 for P2. Males comprised a significantly higher proportion of the patients who developed stones during the first decade of life, with a male:female ratio of 1.9:1. This trend was similar in P1 and P2. In contrast, females comprised a significantly higher proportion of the patients who developed stones during the second decade of life, with a female:male ratio of 1.7:1. This trend was also similar in P1 and P2. There were significant differences in stone composition between P1 and P2. A higher percentage of patients had calcium oxalate stones (CaOx) in P1 compared to P2 (60% versus 47%, p⫽ 0.0019). There was a significant increase in the percentage of patients having calcium phosphate stones (CaP) in P2 compared to P1 (27% versus 18.5 %, p⫽0.008). Twenty-seven patients had recurrent stones. A comparison of the compositions of the first and last stones of patients within this group demonstrated an increase in the proportion of brushite stones (3.7% versus 11.1 %, p⫽0.04). Twenty four hour urine testing was undertaken in 62 children with calcium containing stones (49 CaOx and 13CaP). There were no statistically significant differences in the urinary parameters of patients with CaOx stones compared with patients with CaP stones. CONCLUSIONS: An increasing number of children with kidney stones have CaP calculi. Brushite stones are more prevalent in children with recurrent stone events. The impetus of these shifts is not readily apparent and requires further investigation. Source of Funding: None
Vol. 187, No. 4S, Supplement, Wednesday, May 23, 2012
2301 INFLUENCE OF OBESITY ON 24-HOUR URINE CHEMISTRY STUDIES & RECURRENT UROLITHIASIS IN CHILDREN. In Ho Chang*, Seung Hyun Ahn, Kyung Do Kim, Young Tae Moon, Soon Chul Myung, Joon Young Kim, Se Young Choi, Seoul, Korea, Republic of INTRODUCTION AND OBJECTIVES: Recently studies were reported that obesity increases the risk of urolithiasis in adults. We investigated influence of obesity on 24-hour urine chemistry studies & recurrent urolithiasis in children. METHODS: We identified 189 patients below 18years old with radiographically confirmed first renal or ureteral stone between 1985 and 2010. 125 patients with 24-hour urine chemistry studies evaluation, radioopaque stone, no genitourinary anomalies were evaluated. We measured BMI for each patient, and then calculated BMI percentile (BMIp) which adjusted for sex and age according to 2007 Pediatrics & Adolescent Growth Graph. Patients were stratified into 3 BMI categories. The patients who could follow up more than 1 year were stratified into solitary or recurrent stone formers and evaluated BMIp and 24hour urine chemistry studies in each group. Multivariate analysis with Cox proportional hazard model was performed to assess for independent risk factors for stone recurrence. RESULTS: Among 125 patients, BMI stratification showed LBW in 28 patients, NBW in 71 patients, UBW in 26 patients. And 24-hour urine chemistry studies in each group were not significantly different. The 73 patients(58%) could follow up more than 1 year(mean: 4.95yrs), and 27 patients(37%) were recurrent stone formers. No statistical significance for mean BMIp between solitary and recurrent stone former, while mean citrate value which adjusted for urine creatinine was significantly difference with 2 groups (0.429¡3⁄40.30 vs 0.273¡3⁄40.22, p⬍0.05). The risk factor of urolithiasis in children is hypocitraturia by multivariate analysis (RR, 95%CI: 3.647, 1.04712.703, p⬍0.05), and for patients with hypocitraturia, the 50% median recurrence value is 8 years in analysis with Kaplan Meiers curve. CONCLUSIONS: Unlike adults, obesity is not associated with 24-hour urine chemistry studies is not the risk factor for recurrent urolithiasis in children. Hypocitraturia is the risk factor of urolithiasis in children. Thus, a pathophysiology of urolithiasis in children may be different from that of adults. Source of Funding: None
2302 CYSTINE ANALOGS AS POTENTIAL THERAPEUTIC AGENTS FOR CYSTINURIA Kelly Johnson*, New Brunswick, NJ; Min Yang, Steven Shikhel, Piscataway, NJ; Michael Ward, David Goldfarb, New York, NY; Matthew Lewis, London, United Kingdom; Joseph Barone, New Brunswick, NJ; Jay Tischfield, Amrik Sahota, Piscataway, NJ INTRODUCTION AND OBJECTIVES: Cystinuria urolithiasis stems from mutations in SLC3A1 and/or SLC7A9 genes. Slc3a1 knockout mice excrete cystine in the urine, leading to bladder dysfunction and cystine stones. Cystine analogs such as cystine dimethyl ester (CDME) inhibit crystallization in vitro by attaching to cystine crystal surfaces. We investigated whether CDME could safely be used to inhibit or reduce stone formation in mice. METHODS: 25 two-month old cystinuria male mice were used: 11 control and 14 CDME-treated. CDME (200l of 1mg/ml solution) was administered daily by stomach tube for 4 weeks. Urine samples were analyzed by reverse phase high-performance liquid chromatography and bladders examined by micro computed tomography (CT). RESULTS: 6 of 11 control mice had bladder stones. The number of stones ranged from 1-19 (7.83 ⫹/⫺ 6.46, n⫽47). Stone size was grouped as small: 0.5-2.0mm (41 stones), medium: 3-7mm (5 stones), or large: 9mm (1 stone). Mean stone weight was 55.2 ⫹/⫺ 28.0mg (range 26.8-101.8mg). Mean bladder weight in mice with stones was 82.9 ⫹/⫺ 10.8mg (range 64.9-98.6mg) and in those without
THE JOURNAL OF UROLOGY姞
CONCLUSIONS: Incidence of nephrolithiasis is high postRYGB at a rate of 12.5%. This risk is mitigated in a dose-dependent manner by vitamin D supplementation, and is optimized at 1000IU. Prospective trials are needed to explore the role that vitamin D may play in reducing nephrolithiasis.
Source of Funding: None
2300 CHANGING STONE COMPOSITION PROFILE OF CHILDREN WITH NEPHROLITHIASIS Kyle Wood*, Irina Stanasel, Ross Holmes, Steve Hodges, Patrick Mufarrij, Gordon McLorie, Dean Assimos, Winston-Salem, NC INTRODUCTION AND OBJECTIVES: An increasing number of adult patients with nephrolithiasis have calcium phosphate stones. This is further accentuated in those who are recurrent stone formers. We performed a retrospective study to determine if similar trends are present in children. METHODS: We reviewed records of 179 patients managed from 1992-2010 (0.2 to 18 year olds) for whom stone analysis data were available. Demographic and metabolic data were reviewed. A comparison of patients managed from 1992-2000 (period 1 – P1) and 2001-2010 (period 2 – P2) was undertaken. Statistical analysis included non-parametric Chi-square and Student’s t-Test. RESULTS: The overall average age of manifestation did not differ between the periods (10.6 years in P1 and 11.1 years in P2). Mean age of males was 9.2 for P1 and 10.1 for P2. Mean age for females was 12.0 for P1 and 12.1 for P2. Males comprised a significantly higher proportion of the patients who developed stones during the first decade of life, with a male:female ratio of 1.9:1. This trend was similar in P1 and P2. In contrast, females comprised a significantly higher proportion of the patients who developed stones during the second decade of life, with a female:male ratio of 1.7:1. This trend was also similar in P1 and P2. There were significant differences in stone composition between P1 and P2. A higher percentage of patients had calcium oxalate stones (CaOx) in P1 compared to P2 (60% versus 47%, p⫽ 0.0019). There was a significant increase in the percentage of patients having calcium phosphate stones (CaP) in P2 compared to P1 (27% versus 18.5 %, p⫽0.008). Twenty-seven patients had recurrent stones. A comparison of the compositions of the first and last stones of patients within this group demonstrated an increase in the proportion of brushite stones (3.7% versus 11.1 %, p⫽0.04). Twenty four hour urine testing was undertaken in 62 children with calcium containing stones (49 CaOx and 13CaP). There were no statistically significant differences in the urinary parameters of patients with CaOx stones compared with patients with CaP stones. CONCLUSIONS: An increasing number of children with kidney stones have CaP calculi. Brushite stones are more prevalent in children with recurrent stone events. The impetus of these shifts is not readily apparent and requires further investigation. Source of Funding: None
Vol. 187, No. 4S, Supplement, Wednesday, May 23, 2012
2301 INFLUENCE OF OBESITY ON 24-HOUR URINE CHEMISTRY STUDIES & RECURRENT UROLITHIASIS IN CHILDREN. In Ho Chang*, Seung Hyun Ahn, Kyung Do Kim, Young Tae Moon, Soon Chul Myung, Joon Young Kim, Se Young Choi, Seoul, Korea, Republic of INTRODUCTION AND OBJECTIVES: Recently studies were reported that obesity increases the risk of urolithiasis in adults. We investigated influence of obesity on 24-hour urine chemistry studies & recurrent urolithiasis in children. METHODS: We identified 189 patients below 18years old with radiographically confirmed first renal or ureteral stone between 1985 and 2010. 125 patients with 24-hour urine chemistry studies evaluation, radioopaque stone, no genitourinary anomalies were evaluated. We measured BMI for each patient, and then calculated BMI percentile (BMIp) which adjusted for sex and age according to 2007 Pediatrics & Adolescent Growth Graph. Patients were stratified into 3 BMI categories. The patients who could follow up more than 1 year were stratified into solitary or recurrent stone formers and evaluated BMIp and 24hour urine chemistry studies in each group. Multivariate analysis with Cox proportional hazard model was performed to assess for independent risk factors for stone recurrence. RESULTS: Among 125 patients, BMI stratification showed LBW in 28 patients, NBW in 71 patients, UBW in 26 patients. And 24-hour urine chemistry studies in each group were not significantly different. The 73 patients(58%) could follow up more than 1 year(mean: 4.95yrs), and 27 patients(37%) were recurrent stone formers. No statistical significance for mean BMIp between solitary and recurrent stone former, while mean citrate value which adjusted for urine creatinine was significantly difference with 2 groups (0.429¡3⁄40.30 vs 0.273¡3⁄40.22, p⬍0.05). The risk factor of urolithiasis in children is hypocitraturia by multivariate analysis (RR, 95%CI: 3.647, 1.04712.703, p⬍0.05), and for patients with hypocitraturia, the 50% median recurrence value is 8 years in analysis with Kaplan Meiers curve. CONCLUSIONS: Unlike adults, obesity is not associated with 24-hour urine chemistry studies is not the risk factor for recurrent urolithiasis in children. Hypocitraturia is the risk factor of urolithiasis in children. Thus, a pathophysiology of urolithiasis in children may be different from that of adults. Source of Funding: None
2302 CYSTINE ANALOGS AS POTENTIAL THERAPEUTIC AGENTS FOR CYSTINURIA Kelly Johnson*, New Brunswick, NJ; Min Yang, Steven Shikhel, Piscataway, NJ; Michael Ward, David Goldfarb, New York, NY; Matthew Lewis, London, United Kingdom; Joseph Barone, New Brunswick, NJ; Jay Tischfield, Amrik Sahota, Piscataway, NJ INTRODUCTION AND OBJECTIVES: Cystinuria urolithiasis stems from mutations in SLC3A1 and/or SLC7A9 genes. Slc3a1 knockout mice excrete cystine in the urine, leading to bladder dysfunction and cystine stones. Cystine analogs such as cystine dimethyl ester (CDME) inhibit crystallization in vitro by attaching to cystine crystal surfaces. We investigated whether CDME could safely be used to inhibit or reduce stone formation in mice. METHODS: 25 two-month old cystinuria male mice were used: 11 control and 14 CDME-treated. CDME (200l of 1mg/ml solution) was administered daily by stomach tube for 4 weeks. Urine samples were analyzed by reverse phase high-performance liquid chromatography and bladders examined by micro computed tomography (CT). RESULTS: 6 of 11 control mice had bladder stones. The number of stones ranged from 1-19 (7.83 ⫹/⫺ 6.46, n⫽47). Stone size was grouped as small: 0.5-2.0mm (41 stones), medium: 3-7mm (5 stones), or large: 9mm (1 stone). Mean stone weight was 55.2 ⫹/⫺ 28.0mg (range 26.8-101.8mg). Mean bladder weight in mice with stones was 82.9 ⫹/⫺ 10.8mg (range 64.9-98.6mg) and in those without