Value of repeated analyses of 24-hour urine in recurrent calcium urolithiasis.
OBJECTIVES: The value of repeated analyses of 24-hour urine collections for daily excretion of calcium, uric acid, citrate, phosphorus, and creatinine and for volume and pH performed to detect and classify metabolic disorders in a selected group of calcium stone formers with striking recurrence rates was assessed in a retrospective study. METHODS: A total of 441 urinalyses made over a mean period of 80.4 months of samples obtained from 49 patients were reviewed. Fifty-nine percent of patients were initially found to have metabolic disorders (absorptive hypercalciuria types I and II, hyperuricuria, hypocitraturia) and therefore received specific drug therapy (allopurinol, thiazide, alkali citrate, orthophosphate) for a mean of 45.7 months (group I). The remaining patients were classified as metabolically inactive and were given general metaphylactic instructions (group II). RESULTS: In 73% of patients recurrent stones developed, with no statistically significant difference between the two groups (79% vs 65%). In 55% of group I patients, urinalyses continued to yield abnormal findings during follow-up; however, subsequent abnormal findings were also seen in 40% of the metabolically inactive group II patients. Overall, metabolic disorders were observed at some point in 75% of patients. Only 27% remained recurrence free, and 62% thereof also had pathologic urinary findings. CONCLUSIONS: It does not appear that drug treatment in recurrent calcium urolithiasis based on urinary findings is superior to simple general metaphylactic recommendations, nor that repeated analyses of 24-hour urine collections furnish additional information on the risk of recurrent stone formation or on the presence of risk factors leading to recurrence in the long-term course of disease.
Höbarth, K; Hofbauer, J; Szabo, N
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