EFFECT OF ETIDRONATE TREATMENT ON BONE MASS OF MALE NEPHROLITHIASIS PATIENTS WITH IDIOPATHIC HYPERCALCIURIA AND OSTEOPENIA

Osteopenia is frequently found among calcium stone forming (CSF) patie nts with hypercalciuria. We investigated the effect of a 2-year therap eutic course of etidronate, a bone-sparing agent, in 7 young male CSF patients. The treatment consisted of a cyclic intermittent administrat ion of phosphate followed by sodium etidronate and calcium supplementa tion every 74 days. Bone mineral density (BMD) measured at 12-month in tervals and bone biopsies performed at baseline and after 2 years were the primary efficacy parameters. Mean lumbar spine BMD increased sign ificantly after the 1st year by 2.6 +/- 1.0% (mean +/- SE, p < 0.05) a nd nonsignificantly after the 2nd year by 5.6 +/- 2.6 %. Nonsignifican t changes were observed for femoral neck mean BMD after either the 1st or the 2nd year (decrease of 2.0 +/- 1.0% and 2.0 +/- 3.0%, respectiv ely). Mean histomorphometric parameters showed that bone volume, osteo id volume, and eroded surfaces did not differ from baseline (13.9 +/- 2.2 vs. 12.2 +/- 1.1%, 1.2 +/- 0.7 vs. 2.6 +/- 0.7%, and 20.7 +/- 6.2 vs. 13.7 +/- 1.3%, respectively). Osteoid surface was significantly lo wer than baseline values (9.5 +/- 5.2 vs. 18.8 +/- 5.3%, p < 0.05). Th ese data suggest that etidronate given to young male CSF patients pres enting with hypercalciuria and osteopenia led to a significant amelior ation of BMD, evident only in the lumbar spine after 1 year of treatme nt. There was no histological evidence of long-term improvement in bon e remodeling.