Assessment and significance of abdominal aortic calcification in chronic kidney disease

Background. Abdominal aortic calcification is a common complication and a predictor of cardiovascular mortality in dialysis patients. However, abdominal aortic calcification in pre-dialysis chronic kidney disease (CKD) is poorly understood. Methods. A cohort study of 101 adult Japanese patients (mean age 66.6 ± 11.3 years old) with pre-dialysis CKD (18, 29 and 54 in stages 3, 4 and 5, respectively) was performed. At entry, a non-contrast computed tomography scan was used to determine the abdominal aortic calcification index (ACI). Clinical characteristics and laboratory variables were also assessed. The patients were followed for a mean period of 48 ± 12 months. Results. Among the subjects, 82% had abdominal aortic calcification (50, 83 and 91% for CKD stages 3, 4 and 5, respectively), and the median ACI was 16.7% (8.5, 20.0 and 21.4%, respectively). Multivariate logistic regression analyses identified older age, presence of diabetes and decreased estimated glomerular filtration rate (e-GFR) as independent predictors of the presence (ACI > 0%) and extent (ACI ≥ 20%) of aortic calcification. Multivariate Cox proportional hazards analysis identified ACI ≥ 20% and diabetes as independent predictors for de novo cardiovascular events in CKD stages 4 and 5. Conclusion. Decreased GFR may be associated with the presence and extent of abdominal aortic calcification, and a high level of calcification may be associated with de novo cardiovascular events in pre-dialysis CKD, suggesting that elucidation of the mechanism through which CKD contributes to vascular calcification may lead to an improved prognosis in patients with pre-dialysis CKD.