The progression of vascular calcification and serum osteoprotegerin levels in patients on long-term hemodialysis

Background The aortic calcification index (ACI), estimated on abdominal computed tomographic scans, has been associated with the extent of arteriosclerosis in hemodialysis patients. However, the contribution of biochemical markers to the progression of vascular calcification in patients undergoing hemodialysis is not fully understood. Methods: We examined the relationship between coronary risk factors; metabolic factors, including serum osteoprotegerin (OPG) concentration; and progression of vascular calcification in 26 dialysis patients. Results: Mean patient age was 52.6 +/- 8.7 (SD) years, and mean duration of dialysis therapy was 7.7 +/- 5.8 years. ACI was measured twice in each patient, and the mean interscan period was 4.9 +/- 0.3 years. Mean ACI changed from 22.2 +/- 24.2 to 33.9 +/- 28.8 overall, and mean change in ACI (AACI) was 12.0 +/- 9.9. Patients were divided into 2 groups: slow progressors, with AACI of 4.1 +/- 3.2 (n = 13), and rapid progressors, with DeltaACl of 19.8 +/- 7.9 (n = 13). Serum fasting glucose and CRP levels of rapid progressors were high, and their serum albumin and intact parathyroid hormone levels were low. Multiple regression analyses showed that serum OPG levels were independently associated with vascular calcification in the hemodialysis patients studied. Conclusion: Rapid progression of vascular calcification was associated with dose of calcium carbonate prescribed and serum OPG concentration. The clinical significance of these observations remains to be determined.