Effect of etidronate on urinary calcium / creatinin ratio in postmenopausal women: A prospective, randomized, placebo controlled study

There are both histomorphometric and nonhistomorphometric studies confirming that etidronate reduces bone resorption. In this study, we have examined urinary Calcium/Creatinine ratio (uCA/Cr) as a biochemical marker of bone turnover to show the effectiveness of etidronate and whether it could be used as a follow-up parameter of treatment. Eighty-one postmenopausal women aged 40 to 65 included into the study to investigate the effects of etidronate on uCa/Cr in a prospective, randomised, placebo controlled clinical trial. All necessary criteria matched 81 women were divided into 3 groups at random, each group consisted of 27 patients. Prior to treatment, uCa/Cr was calculated from all subjects 3 hours after drinking 1 liter of water in the morning. Twenty seven (33.3%) women were randomised to oral doses of etidronate (400 mg/day for two weeks followed by drug free period of 10 weeks), twenty seven women to etidronate (400 mg/day for two weeks) plus calcium (1000 mg/day) for the following 10 weeks and twenty seven women to placebo (Fe, 50 mg/day) for 12 weeks. After 12 weeks of treatment, uCa/Cr declined significantly in the etidronate group from 0.118±0.064 to 0.053±0.021, in etidronate+calcium group from 0.08±0.03 to 0.06±0.015 ((p=0.004) and (p=0.005), respectively). In the placebo group no significant change was observed (p=0.03). In conclusion, etidronate is effective in postmenopausal women and the effectiveness of treatment may be followed up by measuring uCa/Cr which is a simple and cheap parameter of determining the effectivensess of etidronate in prevention of osteoporosis. However, since there are contradictory findings concerning uCa/Cr exist, larger clinical and prospective studies should be carried out.