Volume 20, Number 3Original ResearchAccuracy in 24-hour Urine Collection at a Tertiary CenterDean G AssimosKyle WoodCarter BoydDustin WhitakerOmotola AshorobiRobert OsterLisa HarveyRoss P HolmesThere is a paucity of studies addressing the accuracy of 24-hour urine collection for assessing stone risk parameters. Collection accuracy is thought to be essential for assigning optimal therapy for stone prevention. The objective of this study was to determine factors associated with accurate and inaccurate collections. During a 2-year period (2015-2016), 241 stone formers completed 24-hour urine collections. They were divided into accurate collectors (AC), defined as at least one accurate urine collection, and inaccurate collectors (IC). Accuracy was assessed by 24-hour urine creatinine (Cr) excretion indexed to body weight (normal: males, 20-25 mg Cr/kg; females, 15-20 mg Cr/kg). Demographic data analyzed included age, gender, race, insurance status, partner status, income, and education. Statistical analysis methods included the chi-square test, Fisher’s exact test, and the two-group t-test. Average age was 50.7 years at the time of collection; 50.2% were men, 86% were white, and 14% were black. Overall, 51.0% of collections were inaccurate. There was no statistical significance between AC and IC for gender (P = 0.85), race (P = 0.90), insurance status (P = 0.85), recurrence (P = 0.87), stone type (P = 0.57), education (P = 0.35), income (P = 0.42), or poverty (P = 0.35). Older age (P = 0.017) and having a partner (P = 0.022) were significantly associated with AC. The high rate of inaccurate 24-hour urine collections is a concern. The only factors we identified as influencing collection accuracy were age and partner status. These results underscore the importance of developing methods to improve the accuracy of collecting 24-hour urine samples. [Rev Urol. 2018;20(3):119–124 doi: 10.3909/riu0807] © 2018 MedReviews®, LLCKidney stonesMetabolic evaluation24-hour urine collectionaccuracyDemographicsSocioeconomic factors
Volume 21, Number 4Review ArticlesImpact of Demographic Factors and Systemic Disease on Urinary Stone Risk Parameters Amongst Stone FormersOriginal ResearchDean G AssimosKyle WoodWilliam PooreBarbara GowerCarter BoydDustin WhitakerOmotola AshorobiRobert OsterThis article examines via multivariate analysis the associations between demographic factors and systemic diseases on stone risk parameters in a stone-forming population. A retrospective chart review of adult stone formers who completed 24-hour urine collections from April 2004 through August 2015 was performed. Data was collected on age, sex, race, body mass index (BMI), and diagnoses of diabetes and hypertension. CT imaging and renal/abdominal ultrasonography (within ±6 mo) were reviewed for diagnosis of fatty liver disease. Statistical analysis included Pearson and Spearman correlation analysis, and linear and logistic regression analyses, both univariate and multivariate. Five hundred eighty-nine patients were included. Numerous urinary parameters were significant in association with demographic factors or systemic diseases in a multivariate analysis. Older age was associated with decreased calcium (Ca) excretion (P = 0.0214), supersaturation of calcium oxalate (SSCaOx; P = 0.0262), supersaturation of calcium phosphate (SSCaP; P < 0.0001), and urinary pH (P = 0.0201). Men excreted more Ca (P = 0.0015) and oxalate (Ox; P = 0.0010), had lower urine pH (P = 0.0269), and higher supersaturation of uric acid (SSUA; P < 0.0001) than women. Blacks had lower urine volume (P = 0.0023), less Ca excretion (P = 0.0142), less Ox excretion (P = 0.0074), and higher SSUA (P = 0.0049). Diabetes was associated with more Ox excretion (P < 0.0001), lower SSCaP (P = 0.0068), and lower urinary pH (P = 0.0153). There were positive correlations between BMI and Ca excretion (P = 0.0386), BMI and Ox excretion (P = 0.0177), and BMI and SSUA (P = 0.0045). These results demonstrate that demographic factors and systemic disease are independently associated with numerous risk factors for kidney stones. The mechanisms responsible for these associations and disparities (racial differences) need to be further elucidated. [Rev Urol. 2019;21(4):158–165] © 2020 MedReviews®, LLCObesityKidney stonesDiabetesSystemic diseaseFatty Liver