2259 LONGER INTERVAL FROM STONE ANALYSIS TO URINALYSIS LEADS TO DIFFERENCES ON 24-HOUR URINE COLLECTIONS

You have accessJournal of UrologyStone Disease: Evaluation & Medical Management (II)1 Apr 20132259 LONGER INTERVAL FROM STONE ANALYSIS TO URINALYSIS LEADS TO DIFFERENCES ON 24-HOUR URINE COLLECTIONS Justin Friedlander, Daniel Moreira, Chris Hartman, Sammy Elsamra, Arthur Smith, and Zeph Okeke Justin FriedlanderJustin Friedlander New Hyde Park, NY More articles by this author , Daniel MoreiraDaniel Moreira New Hyde Park, NY More articles by this author , Chris HartmanChris Hartman New Hyde Park, NY More articles by this author , Sammy ElsamraSammy Elsamra New Hyde Park, NY More articles by this author , Arthur SmithArthur Smith New Hyde Park, NY More articles by this author , and Zeph OkekeZeph Okeke New Hyde Park, NY More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2168AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Twenty four hour urine collections are routinely performed in patients with recurrent nephrolithiasis, as well as those at increased risk for further stone formation. At present there is no standard for timing of urine collection in relation to passage or surgical treatment of stones. We examined 24-hour urine composition in patients according to timing of stone analysis. METHODS We performed a retrospective review of stone clinic patients with a stone composition analysis and 24-hour urinalysis (Litholink®). Univariable analysis comparing patients who had analyses <6 months apart and patients who had ≥6 months difference was performed with the t-test. Multivariable linear regression models were adjusted for clinical and demographic factors, and 24-hour urine constituents. RESULTS A total of 508 patients were included in the final analysis, 398 (78%) who had 24-hour urinalysis <6 months from stone analysis and 110 (22%) who had ≥6 months difference between evaluations. Univariable analysis demonstrated significant differences for 24-hour mean urinary calcium, oxalate, citrate, uric acid, sodium, potassium, magnesium, sulfate, phosphate, creatinine, and supersaturation (SS) of calcium oxalate (CaOx) and calcium phosphate (CaP; Table 1). Adjusted multivariable analysis found that compared to patients who had analysis <6 months apart, patients who had analysis ≥6 months apart had significantly higher 24-hour urinary calcium (mean difference=37.74mg, p=0.0017), magnesium (9.71mg, p=0.03), sulfate (3.24 mmol, p=0.02), creatinine (131.9 mg, p<0.001), SS CaOx (1.19, p<0.001), and SS CaP (0.303, p=0.001; Table 2). CONCLUSIONS Our analysis demonstrated that urinary calcium, magnesium, sulfate, SS CaOX, and SS CaP are all higher with a longer interval between stone analysis and urine collection. These findings must be accounted for in patient counseling and treatment, and reinforce the necessity of close and careful follow-up for stone clinic patients. Table 1. Univariable analysis of 24-hour urine chemistry by time between studies < 6 months ⩾ 6 months p-value BMI 30.1(±7.6) 30.6(±7.7) 0.59 pH 5.97(±0.58) 6.04(±0.58) 0.30 Calcium (mg) 189.7(±115.3) 246.0(±133.8) < 0.001 Oxalate (mg) 38.2(±15.2) 44.5(±19.9) 0.002 Citrate (mg) 482.0(±310.7) 559.9(±376.8) 0.049 Uric acid (g) 0.68(±0.25) 0.77(±0.26) 0.001 Sodium (mmol) 170.8(±77.8) 194.2(±70.4) 0.003 Potassium (mEq) 59.2(±29.0) 65.4(±22.8) 0.019 Magnesium (mg) 92.9(±45.4) 109.4(±48.9) 0.002 Sulfate (mmol) 40.9(±18.3) 48.8(±18.4) < 0.001 Phosphate (g) 0.92(±0.38) 1.06(±0.41) 0.002 Creatinine (mg) 1543(±534.2) 1720(±530.5) 0.002 Volume (L) 1.87(±0.82) 2.01(±0.80) 0.11 SS CaOx 6.69(±3.56) 7.86(±3.94) 0.006 SS CaP 0.98(±0.87) 1.29(±1.00) 0.001 SS UA 1.18(±0.95) 1.12(±0.95) 0.51 Table 2. Multivariable adjusted differences in 24-hour urine composition Parameter Difference Standard error p-value pH 0.058 0.056 0.30 Calcium (mg) 37.74 11.99 0.0017 Oxalate (mg) 49.97 33.82 0.14 Citrate (mg) 2.76 1.60 0.08 Uric acid (g) 0.032 0.02 0.11 Sodium (mmol) 7.39 6.27 0.24 Potassium (mEq) 1.72 2.52 0.49 Magnesium (mg) 9.71 4.52 0.03 Sulfate (mmol) 3.24 1.41 0.02 Phosphate (g) 0.036 0.028 0.21 Creatinine (mg) 131.9 39.2 < 0.001 Volume (L) 0.097 0.089 0.27 SS CaOx 1.19 0.35 < 0.001 SS CaP 0.303 0.094 0.001 SS UA −0.048 0.086 0.58 Referent to patients who had analyses < 6 months apart © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e926-e927 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Justin Friedlander New Hyde Park, NY More articles by this author Daniel Moreira New Hyde Park, NY More articles by this author Chris Hartman New Hyde Park, NY More articles by this author Sammy Elsamra New Hyde Park, NY More articles by this author Arthur Smith New Hyde Park, NY More articles by this author Zeph Okeke New Hyde Park, NY More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...