Defining hypercalciuria in nephrolithiasis
The classic definition of hypercalciuria, an upper normal limit of 200mg/day, is based on a constant diet restricted in calcium, sodium, and animal protein; however, random diet data challenge this. Here our retrospective study determined the validity of the classic definition of hypercalciuria by c...
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Published in: | Kidney international Vol. 80; no. 7; pp. 777 - 782 |
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Main Authors: | , , , , , |
Format: | Journal Article |
Language: | English |
Published: |
Basingstoke
Elsevier Inc
01-10-2011
Nature Publishing Group Elsevier Limited |
Subjects: | |
Online Access: | Get full text |
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Summary: | The classic definition of hypercalciuria, an upper normal limit of 200mg/day, is based on a constant diet restricted in calcium, sodium, and animal protein; however, random diet data challenge this. Here our retrospective study determined the validity of the classic definition of hypercalciuria by comparing data from 39 publications analyzing urinary calcium excretion on a constant restricted diet and testing whether hypercalciuria could be defined when extraneous dietary influences were controlled. These papers encompassed 300 non-stone-forming patients, 208 patients with absorptive hypercalciuria type I (presumed due to high intestinal calcium absorption), and 234 stone formers without absorptive hypercalciuria; all evaluated on a constant restricted diet. In non-stone formers, the mean urinary calcium was well below 200mg/day, and the mean for all patients was 127±46mg/day with an upper limit of 219mg/day. In absorptive hypercalciuria type I, the mean urinary calcium significantly exceeded 200mg/day in all studies with a combined mean of 259±55mg/day. Receiver operating characteristic curve analysis showed the optimal cutoff point for urinary calcium excretion was 172mg/day on a restricted diet, a value that approximates the traditional limit of 200mg/day. Thus, on a restricted diet, a clear demarcation was seen between urinary calcium excretion of kidney stone formers with absorptive hypercalciuria type I and normal individuals. When dietary variables are controlled, the classic definition of hypercalciuria of nephrolithiasis appears valid. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Review-3 |
ISSN: | 0085-2538 1523-1755 |
DOI: | 10.1038/ki.2011.227 |