Clinical Nephrology – Epidemiology – Clinical Trials
Kidney International (2004) 66, 2032–2037; doi:10.1111/j.1523-1755.2004.00975.x
Relative effect of urinary calcium and oxalate on saturation of calcium oxalate Rapid Communication
CHARLES Y C PAK, BEVERLEY ADAMS-HUET, JOHN R POINDEXTER, MARGARET S PEARLE, ROY D PETERSON and ORSON W MOE
Center for Mineral Metabolism and Clinical Research, The University of Texas Southwestern Medical Center, Dallas, Texas
Correspondence: Dr Charles Y.C. Pak, Center for Mineral Metabolism and Clinical Research, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8571. E-mail:charles.pak@utsouthwestern.edu
Received 29 March 2004; Revised 20 May 2004; Accepted 8 June 2004.
Abstract
Relative effect of urinary calcium and oxalate on saturation of calcium oxalate.
Background
The study compared the effect of urinary calcium with that of oxalate on urinary saturation [relative saturation ratio (RSR)] of calcium oxalate.
Methods
A retrospective data analysis was conducted on urinary stone risk analysis from 667 patients with predominantly calcium oxalate stones. Urinary RSR of calcium oxalate was individually calculated using Equil 2. A "theoretical" curve of the relationship between urinary RSR of calcium oxalate and concentration of calcium or oxalate was obtained at two stability constants for calcium oxalate complex, while varying calcium or oxalate and using group mean values for urinary constituents.
Results
At the stability constant of 7.07 
103, the increase in RSR of calcium oxalate was less marked with calcium than with oxalate. However, at the stability constant of 2.746 103 from the Equil 2 that is considered the "gold standard," calcium and oxalate were equally effective in increasing RSR of calcium oxalate. The above theoretical curves (relating RSR with calcium or oxalate) were closely approximated by the actual curves constructed with data from individual urine samples. Urinary saturation of calcium oxalate was equally dependent on urinary concentrations of calcium and oxalate (r = 0.75 unadjusted and 0.57 adjusted for variables, and P < 0.0001 for calcium; r = 0.73 unadjusted and 0.60 adjusted, P <0.0001 for oxalate).
Conclusion
Among calcium oxalate stone-formers, urinary calcium is equally effective as urinary oxalate in increasing RSR of calcium oxalate.
Keywords:
calcium oxalate saturation, urinary calcium, oxalate
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated
RESEARCH
A catalytic DNA for porphyrin metallation
Nature Structural Biology Correspondence (01 Sep 1996)
Journal of Cerebral Blood Flow & Metabolism Brief Communication
Effect of dietary modification on urinary stone risk factors
Kidney International Original Article
Schedule of taking calcium supplement and the risk of nephrolithiasis
Kidney International Original Article
Bone mineral density and urine calcium excretion among subjects with and without nephrolithiasis
Kidney International Original Article
