Dietary management of idiopathic hyperoxaluria and the influence of patient characteristics and compliance.
OBJECTIVE
To assess the efficacy of dietary management for the treatment of idiopathic hyperoxaluria in a large tertiary care center and examine the influence of patient factors, compliance, and follow-up on oxalate reduction, which has not been previously investigated.


METHODS
Retrospectively, 149 patients with kidney stones with idiopathic hyperoxaluria who received dietary management at our stone clinic were evaluated. Changes in urinary parameters on 24-hour urine collections were calculated for all patients and those with abnormal values in the overall short-term (30-240 days) and long-term (>240 days) time periods. Changes in urinary oxalate were evaluated with respect to patient characteristics and compliance measures.


RESULTS
Urine oxalate and supersaturation of calcium oxalate were significantly (P < .001) reduced by 8.9 ± 19.2 mg/d and 1.7 ± 4.3, respectively. A total of 48.3% of the patients reduced their urinary oxalate to normal. Urine oxalate reductions were similar in the short-term and long-term periods. Women lowered urine oxalate nearly twice as much as men (12.7 ± 2.0 mg/d vs 6.7 ± 2.2 mg/d, P = .022) and body mass index (BMI) negatively correlated with oxalate reduction (Pearson's r = -0.213). Reported noncompliance and keeping follow-up appointments did not affect oxalate, however, there was a significant correlation between increasing urine volume and reducing oxalate (Pearson's r = -0.21).


CONCLUSIONS
This study confirms that meaningful reductions of urine oxalate and supersaturation of calcium oxalate can be achieved with dietary management of hyperoxaluria on a larger clinical scale. Furthermore, we identified that women and patients with low BMIs had greater urine oxalate reductions and urine volume may also be used by clinicians as a measure of dietary compliance.
Department of Urology, University of Pittsburgh Medical Center, Pittsburgh, PA. Electronic address: zschwen21@gmail.com.
Zeyad R
ZR
Schwen
Julie M
JM
Riley
Yaniv
Y
Shilo
Timothy D
TD
Averch
D000328:Adult; D015992:Body Mass Index; D002129:Calcium Oxalate / Q000378:metabolism; D005260:Female; D006801:Humans; D006959:Hyperoxaluria / Q000150:complications / Q000178:diet therapy*; D007669:Kidney Calculi / Q000150:complications / Q000652:urine; D008297:Male; D008875:Middle Aged; D010070:Oxalates / Q000652:urine; D010349:Patient Compliance; D012189:Retrospective Studies; D016896:Treatment Outcome
D010070:Oxalates; D002129:Calcium Oxalate