Calcium-loading test and bone disease in patients with urolithiasis.

A group of 121 patients with a history of multiple or complicated calcium urolithiasis were divided into three subgroups: normal, absorptive and renal/resorptive calciuria by means of a calcium-loading test. Patients with renal hypercalciuria had lower bone mineral content (BMC) than the other groups but did not differ in amount of bone or TmPO4/GFR. The 24-hour urine calcium excretion was elevated in patients with renal and absorptive type of hypercalciuria but not in patients with normal calcium-loading test and there was no correlation to BMC. The c-AMP/creatinine seemed to discriminate patients with resorptive calciuria from patients with renal calciuria. It is suggested that only patients with renal hypercalciuria should be treated with calcium-retaining drugs such as thiazides.