[Compared metabolic effects of phosphorus or hydrochlorothiazide therapy in hypercalciuric stone-formers (author's...

The hypocalciuric effect of phosphorus or hydrochlorothiazide therapy was evaluated in 26 hypercalciuric stone-formers after 2 to 4 months and 8 to 12 months treatment. After 2 to 4 months, a significant decrease of the urinary calcium to creatinine ratio was noted only in a group of 7 patients receiving phosphorus supplementation (1500 mg/day). The decrease was transient however, since in 5 of these patients, the calcium to creatinine ratio was found to be at pretreatment levels when the patients were reinvestigated after 8 to 12 months on phosphorus. In contrast, in 8 patients receiving hydrochlorothiazide (50 mg/day) during 8 to 12 months, this ratio was significantly lower (P less than 0.01) than before treatment. A group of patients maintained on high water intake alone for 8 to 12 months served as a control and no modification in calcium excretion was observed. This study indicates that long-term treatment with hydrochlorothiazide is more efficient in lowering urinary calcium excretion than phosphorus therapy.