Effect of etidronic acid on arterial calcification in dialysis patients

Background: Bisphosphonate drugs, including etidronic acid, are effective agents for the treatment of osteoporosis and may reduce arterial calcification. The aim of this randomised control trial was to characterise the effect of etidronic acid on arterial calcification in patients undergoing chronic haemodialysis. Methods: Patients undergoing chronic haemodialysis were assigned to one of two groups by a simple randomisation method: an etidronic acid group (n = 8; 400 mg/day for 24 weeks) and a control group (n = 6; no etidronic acid therapy). Serum calcium, phosphate, calcium-phosphate product, alkaline phosphatase, lactate dehydrogenase, activated colecalciferol and parathyroid hormone levels were measured at baseline and then at 4-weekly intervals thereafter. Results: Calcification scores of the coronary arteries and the thoracic and abdominal aorta were determined by volume-correcting data collected by a multi-detector-row computerised tomographic scanner at baseline, at 6 months and at 1 year. Two patients in the etidronic acid group were excluded from the final analysis because of medical complications. The remainder of the patients (n = 6) showed no significant temporal changes in serum levels of assessed parameters. While no significant temporal changes in coronary calcification score were observed in either group, the mean aortic calcification score significantly decreased over time from 1000 +/- 460mm(3) at baseline to 970 +/- 580mm(3) at the completion of treatment and 350 +/- 180mm(3) at 1 year (p = 0.009), corresponding to a mean percentage decrease of -64.1% (range -86.5% to -50.1%). By contrast, in the control group, the mean aortic calcification score significantly increased with time from 1460 +/- 1280mm(3) to 1510 +/- 1150mm(3) at the completion of treatment and 2070 +/- 1200mm(3) at 1 year (p = 0.006), corresponding to a mean percentage change in the calcification score of +130.0% (range 2.1-414%). Conclusion: Etidronic acid markedly reduced aortic calcification in patients with end-stage renal disease undergoing chronic haemodialysis. The effect of this agent on aortic calcification may attenuate the increase in aortic stiffness and result in improved long-term outcomes in patients undergoing chronic haemodialysis.