[Study on vascular calcification in patients on continuous ambulatory peritoneal dialysis (CAPD): special reference to active vitamin D (VD) treatment].

Cardiovascular complications, such as vascular calcification (VC), have been a major concern in patients undergoing chronic dialysis. The pathogenesis of this VC has been attributed to the altered calcium and phosphate metabolism, but the contributing factors have not been clarified. In order to investigate these factors, 38 CAPD patients were divided into two sub-groups according to the absence of aortic calcification (Group-A; n = 18) or the presence of aortic calcification (Group-B; n = 20). The number of elderly patients was larger and the duration of CAPD was longer in Group-B than in Group-A. Calcium and phosphate metabolism and serum lipids levels did not differ significantly between groups and the number of patients given VD was 8/18 in Group-A and 14/20 in Group-B. In order to explore the progression of VC in CAPD patients given long-term treatment with VD, 22 patients who were matched for the duration of CAPD were analyzed. These were divided into two sub-groups according to whether they were treated with VD (Group-C; n = 11) or not treated with VD (Group-D; n = 11). Radiological findings (such as the degree of aortic calcification), bone mineral content, divalent ions, parathyroid hormone levels and lipid profiles were examined. The prevalence of patients with aortic calcification was significantly higher in Group-D than in Group-C (7/11 v. s. 2/11, P < 0.05). However, lipids, mineral and endocrinological parameters did not differ between the sub-groups. No significant difference in the calcium and phosphate balance was observed. The bone mineral content revealed no difference between both of the sub-groups. VD administration by conventional mode, even without significant suppression of PTH or increase of bone mineral content, may enhance vessel calcification in patients on long-term CAPD.