Adequate or not? A comparison of 24-hour urine studies for renal stone prevention by creatinine to weight ratio

Mark D. Sawyer, Mary S. Dietrich, Ryan Pickens, S. Duke Herrell, Nicole L. Miller

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Purpose: The intent of this study was to compare urine parameters between kidney stone formers with low, expected, and high creatinine to weight ratio (Cr/kg) and to discuss implications for treatment. Patients and Methods: In this retrospective study, 381 stone formers (205 females and 176 males) with urine collections for nephrolithiasis evaluation were included. Using the first collected sample, patients were grouped into low, expected, and high Cr/kg using sex appropriate reference ranges (15.0-20.0 mg/kg for females and 18.0-24.0 mg/kg for males) and evaluated. Results: Of initial collections, 50.7% were outside the Cr/kg reference range. Median age increased as Cr/kg decreased with 13 years age difference between low (56) and high (43) groups. Body mass index and weight also increased significantly with decreased ratio. No significant difference between groups was found for urine volume, total oxalate, oxalate concentration, pH, and supersaturations of calcium oxalate and uric acid. Total calcium, sodium, citrate, calcium concentration, supersaturation of calcium phosphate, and other parameters significantly increased with increased Cr/kg for the cohort. Conclusions: To our knowledge, this is the first study to thoroughly evaluate the impact of Cr/kg on urine parameters. Clinicians should be cognizant of limitations of Cr/kg for evaluating collection adequacy. It is especially important to consider Cr/kg when there is potential for undertreatment or overtreatment of patients with abnormal Cr/kg. Studies demonstrating hypercalciuria and high Cr/kg may need to be repeated before starting thiazide diuretics. Further studies are needed to determine how to better interpret urine components that vary with Cr/kg ratio.

Original languageEnglish (US)
Pages (from-to)366-369
Number of pages4
JournalJournal of Endourology
Volume27
Issue number3
DOIs
StatePublished - Mar 1 2013
Externally publishedYes

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Creatinine
Urine
Kidney
Weights and Measures
Oxalates
Reference Values
Calcium Citrate
Sodium Chloride Symporter Inhibitors
Hypercalciuria
Nephrolithiasis
Urine Specimen Collection
Calcium Oxalate
Kidney Calculi
Uric Acid
Body Mass Index
Retrospective Studies
Calcium
Therapeutics

All Science Journal Classification (ASJC) codes

  • Urology

Cite this

Adequate or not? A comparison of 24-hour urine studies for renal stone prevention by creatinine to weight ratio. / Sawyer, Mark D.; Dietrich, Mary S.; Pickens, Ryan; Herrell, S. Duke; Miller, Nicole L.

In: Journal of Endourology, Vol. 27, No. 3, 01.03.2013, p. 366-369.

Research output: Contribution to journalArticle

Sawyer, Mark D. ; Dietrich, Mary S. ; Pickens, Ryan ; Herrell, S. Duke ; Miller, Nicole L. / Adequate or not? A comparison of 24-hour urine studies for renal stone prevention by creatinine to weight ratio. In: Journal of Endourology. 2013 ; Vol. 27, No. 3. pp. 366-369.
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