Coronary calcification in hemodialysis patients: The contribution of traditional and uremia-related risk factors

Background. Coronary artery calcification is a common feature of atherosclerosis, occurring in 90% of angiographically significant lesions. There is recent evidence that coronary artery calcification is frequent in hemodialysis patients and it has been suggested that this increased incidence may be associated to uremia-related factors. The development and progression of coronary artery calcification is similar to osteogenesis. The aim of this study was to evaluate the relationship between coronary artery calcification, uremia-related factors, and bone histomorphometry in hemodialysis patients. Methods. A total of 101 hemodialysis patients were assessed for biochemical markers of inflammation, oxidative stress, and bone metabolism. Subsequently, they were submitted to multislice coronary tomography (MSCT) and transiliac bone biopsy. Results. The median calcium score was 116.2 (range 0 to 5547). Fifty-two percent of the patients showed moderate and severe coronary artery calcification, 20% had calcium scores greater than 1000. In univariate analysis, age (r= 0.57, P < 0.000001), osteoprotegerin (OPG) (r= 0.44, P= 0.00002), and body mass index (BMI) (r= 0.24, P= 0.01) correlated positively with calcium score. Bone trabecular volume and trabecular thickness correlated negatively with calcium score (r=-0.24, P= 0.02; r=-0.22, P= 0.03). There was a correlation of borderline significance between calcium score and C-reactive protein (CRP) (r= 0.18, P= 0.062). The multiple linear regression analysis identified OPG as the only variable independently associated with coronary artery calcification. Conclusion. Coronary artery calcification is highly prevalent in the hemodialysis population and is associated with older age, higher BMI, inflammation and reduced trabecular bone volume. Higher OPG is independently associated with coronary artery calcification and may represent an incomplete self-defensive response to the progression of atherosclerosis in hemodialysis patients.