MP41-13 VITAMIN D REPLACEMENT IN RECURRENT RENAL STONE FORMERS WITH HYPERCALCIURIA DOES NOT INCREASE URINE CALCIUM EXCRETION OR RENAL STONE GROWTH

Abstract

You have accessJournal of UrologyStone Disease: Medical Therapy1 Apr 2015MP41-13 VITAMIN D REPLACEMENT IN RECURRENT RENAL STONE FORMERS WITH HYPERCALCIURIA DOES NOT INCREASE URINE CALCIUM EXCRETION OR RENAL STONE GROWTH Luke McGuinness, Robert Calvert, and Vinita Mishra Luke McGuinnessLuke McGuinness More articles by this author , Robert CalvertRobert Calvert More articles by this author , and Vinita MishraVinita Mishra More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1641AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Reduced vitamin D levels are found in up to 50% of recurrent renal stone patients. Reluctance to replace vitamin D in these patients exists due to a theoretical risk of increased intestinal calcium absorption and subsequent renal excretion. Recent evidence suggests that increased absorption might be offset by increased bone deposition with no effect on urine excretion. We aim to assess the effect of pharmacological correction of low vitamin D in hypercalciuric renal stone formers compared to those with adequate vitamin D in a metabolic stone clinic. METHODS Retrospective review of 30 recurrent renal stone formers with hypercalciuria was undertaken. Serum 25 hydroxyvitamin D (25OHD) and 24hr urine biochemistry were measured in all patients at baseline and during follow-up. Renal stone growth was assessed with abdominal x-rays. Hypercalciuria was treated with diet and diuresis advice and pharmacotherapy (thiazide/ potassium citrate/allopurinol). Those with low 25OHD levels (¡Ü50nmol/L) were prescribed vitamin D replacement (VDR). Outcomes of 24hr urine biochemistry and new stone growth were compared between those on VDR (n= 17) and those with adequate 25OHD levels (n= 13). RESULTS Nine patients (30%) had vitamin D deficiency (¡Ü30nmol/L), 8 (27%) had insufficiency (>30 and ¡Ü50nmol/L) and 13 (43%) had adequate levels (>50nmol/L). 17 patients were prescribed vitamin D replacement (mean duration 14 months). 13 patients with adequate levels had mean follow-up of 22 months. No significant difference in baseline 24hr urine biochemistry was seen. Patients on VDR had an increase in 25OHD (33.6 to 74.7nmol/L, p<0.001) whilst 24hr urine calcium levels reduced non-significantly (9.33 to 8.78mmol/24hr, p>0.1). Patients with adequate 25OHD level (64.7nmol/L) had a significant decrease in urinary calcium (10.6 to 8.28mmol/24hr, p=0.003). No other significant changes were seen on urine biochemistry. The mean decrease in urine calcium in those on VDR (0.43mmol/24hr) compared to those with adequate 25OHD (2.28mmol/24hr) was not significant (p=0.15). 10 patients had new stone growth; 6 patients (35%) on VDR and 4 patients (31%) with adequate 25OHD (p>0.5). CONCLUSIONS Low vitamin D levels are present in more than half of hypercalciuric stone formers. Vitamin D replacement does not adversely affect urine calcium levels in patients with low vitamin D status or increase renal stone risk compared to those with adequate levels. Furthermore a beneficial effect may exist due to increased bone mineralisation but further evaluation is required. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e505 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Luke McGuinness More articles by this author Robert Calvert More articles by this author Vinita Mishra More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...