Metabolic Abnormalities of 24-hour Urinary Lithogenic Factors in Recurrent Stone Formers

Lee, Seok Young; Lee, Sang Cheol; Kim, Wun Jae

Abstract

PURPOSE: To determine the metabolic characteristics of recurrent stone formers (RSF), we investigated urinary lithogenic factors.
MATERIALS AND METHODS
The 24-hour urine samples of 151 RSF (114 men, 37 women) and 70 normal controls (33 men, 37 women) were analyzed for excretion rate differences of lithogenic and inhibitory constituents such as volume, sodium, phosphorus, uric acid, calcium, magnesium, oxalate, and citrate. The incidence and spectrum of metabolic abnomality in REF were aldo determined.
RESULTS
The RSF showed significantly increased excretion of phosphorus (p=0.004), uric acid (p=0.003), and calcium (p=0.007) and decreased in that of citrate (p=0.044). No significant differences were found between the RSF and normal controls with regard to the excretions of sodium, magnesium, oxalate, and volume. The most frequent metabolic abnormality in RSF was hypocitraturia (43.7%), followed by hypernatriuria (41.7%), hypercalciuria (23.2%), and hyperuricosuria (20.5%). At least one metabolic abnormality was found in 118 of out of 151 RSF (78.1%).
CONCLUSIONS
Our results showed that RSF had different urinary excretions of citrate as well as phophorus, uric acid, and calcium compared to the normal subjects and metabolic abnomalities were found up to 80% of them. The 24-hour urine study would be an effective means for metabolic evaluation in RSF although diagnostic accuracy increases with repeated examination.