Effects of hydrochlorothiazide and dietary sodium restriction on calcium metabolism in corticosteroid treated patients.

The effect of treatment with hydrochlorothiazide (HCT) and dietary sodium restriction on calcium economy in glucocorticoid-treated patients was investigated. Fractional 47Ca intestinal absorption (FCaA) and fractional urinary calcium excretion (FCaEx) were measured in six normal individuals and in ten patients receiving glucocorticoids for chronic obstructive pulmonary disease before and after 60 days of treatment with a 50 mEq sodium diet and HCT 50 mg twice daily. FCaA was significantly decreased on glucocorticoid-treated patients (27.5 +/- 4.3%) when compared to normal individuals (41.8 +/- 2.8%, p less than 0.005). A significant increase in FCaA to 38.9 +/- 4.8%, (P less than .05) was seen in glucocorticoid-treated patients after treatment with HCT and dietary sodium restriction. Baseline FCaEx was higher in glucocorticoid-treated patients than in the normal subjects. A significant decrease in FCaEx after dietary sodium restriction and thiazide administration occurred in both normal (0.99 +/- 0.28% before vs. 0.69 +/- 0.30% after; p less than .025) and glucocorticoid-treated patients (1.46 +/- 0.19% before vs. 0.73 +/- 0.13% after p; less than 0.025). These data suggest that dietary sodium restriction and HCT therapy may improve total body calcium economy in glucocorticoid-treated patients by increasing intestinal calcium absorption and decreasing urinary calcium excretion.