Efficasy of a citrate-enriched mineral beverage in the prevention of calcium urolithiasis

Background: The aim of our study was to evaluate the efficacy of a new citrate-enriched natural mineral beverage in the prevention of calcium stone formation in the urinary tract. Methods: Thirty-four patients, 16 male and 18 female, between 23 and 71 years of age (average 50.9 years), participated in a prospective, randomized, single-blind study that lasted two years. The patients were randomly divided into a study group (16 patients) and a control group (18 patients). All patients suffered from recurrent urinary calcium stone disease, with at least one recurrence experienced within the previous two years. Before the start of the study, we evaluated the patients dietary habits and fluid intake, recorded the demographic and vital data, performed a blood count, biochemical analysis of blood and analysis of a 24-hour urine specimen, and obtained a plain x-ray film and/or ultrasound scan of the urinary tract to establish the presence of any urinary stones. Over the following two years, the patients of the study group drank 500 ml of the citrate-enriched mineral beverage daily, while the patients of the control group drank the same quantity of plain water. At the end of this treatment, each patient's health status was assessed and the initial laboratory investigations were repeated. Statistical analysis of the results was performed with the use of the chi-square test, Fischer's test and the Cochram-Mante-Haenszel test for qualitative variables; the two-tailed t test (comparison between groups) and the paired t test (comparisons within individual group) were used for quantitative variables. Results: At the end of the 24-month treatment period, there were no significant differences between the groups in any values of the blood cell count, biochemical parameters of blood or parameters of 24-hour urine. Results for the study group showed a significant increase in urinary magnesium (p = 0.0047), phosphate (p = 0.0103) and citrate (p = 0.0410) over the baseline values. In the control group, values for 24-hour urine showed a significant decrease in specific gravity (p = 0.0137) and a significant increase in the levels of calcium (p = 0.0382) and magnesium (p = 0.0068). In the study group, the calcium/magnesium ratio in urine was significantly below the baseline value (p = 0.0049). The number of stones in the urinary tract did not differ significantly between the two groups either before (p = 0.7125) or after the treatment (p = 0.2297). Eighty-eight per cent of patients in the study group and 83% of those in the control group were satisfied or highly satisfied with the treatment received. Two patients in the study group and one in the control group were excluded from the study because of gastrointestinal intolerance. Conclusions: On the basis of our study, we can conclude that the citrate-enriched mineral beverage might prove an effective inhibitor of calcium stone formation in the urinary tract. This is supported mainly by the observed significant increase in urolithiasis inhibitors.