PD17-04 MAGNESIUM SUPPLEMENTATION IMPROVES URINARY CITRATE EXCRETION IN THE METABOLIC STONE CLINIC SETTING

Abstract

You have accessJournal of UrologyStone Disease: Medical & Dietary Therapy I1 Apr 2018PD17-04 MAGNESIUM SUPPLEMENTATION IMPROVES URINARY CITRATE EXCRETION IN THE METABOLIC STONE CLINIC SETTING Natasza Posielski, Roy A. Jhagroo, Stephen Y. Nakada, and Kristina L. Penniston Natasza PosielskiNatasza Posielski More articles by this author , Roy A. JhagrooRoy A. Jhagroo More articles by this author , Stephen Y. NakadaStephen Y. Nakada More articles by this author , and Kristina L. PennistonKristina L. Penniston More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.966AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Urinary citrate (UCit) excretion is a well-described target of medical management of calcium stones. Urinary magnesium (UMg) excretion has been linked with UCit excretion, but this relationship has received little attention, especially in the context of medical management for hypocitraturia. We hypothesized that Mg supplementation could increase UMg in patients with lower excretion and that lower UCit excretion would be more favorably addressed with higher UMg excretion. METHODS With IRB approval, patients with low UMg (defined as ≤70mg/day) in their first urine collection were identified from patients seen between 2009-2016 in our multidisciplinary stone clinic. Those without two 24-hour urine collections, with >40% difference in urinary creatinine excretion, or >2 years between collections were excluded. Patients were separated into two groups based on those to whom over-the-counter Mg supplementation (300-500 mg/d) was recommended at baseline. Primary outcome measures included changes in UMg and UCit excretion. RESULTS Of 117 patients (age 57±16 y; M:F 48:69) meeting inclusion criteria, 40 (34%) were recommended Mg supplementation (Mg+) while 77 (66%) were not (no-Mg), although increased dietary Mg may have been suggested in some cases. The prevalence of patients with a history of calcium-containing stones was not different between groups (83 vs 100% for Mg+ and no-Mg groups, p=0.16). There was no difference in alkali prescription prevalence (50 and 53% for Mg+ and no-Mg groups) nor in baseline UCit excretion (352 vs 415 mg/d for Mg+ and no-Mg groups; p=0.26). A rise in UMg was observed (54 to 72 and 46 to 67 mg/d within Mg+ and no-Mg groups; p<0.001 for both, paired t-tests). Yet UCit increased only in the supplemented group (figure, A). Change in UCit differed by baseline UMg status and treatment group (figure, B). Among only patients with hypocitraturia (defined as <340 mg/d, prevalence 48% for both groups), UCit increased only in the Mg+ group (140 to 243, p=0.003; vs 176 to 209 mg/d for no-Mg). CONCLUSIONS Low UMg excretion was effectively increased with Mg supplementation. Moreover, lower UCit excretion increased significantly in patients on Mg supplementation vs. those not. Our results suggest that certain patients may require correction of low UMg as part of medical management for hypocitraturia. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e385 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Natasza Posielski More articles by this author Roy A. Jhagroo More articles by this author Stephen Y. Nakada More articles by this author Kristina L. Penniston More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...