High Parathyroid Hormone Level and Osteoporosis Predict Progression of Coronary Artery Calcification in Patients on Dialysis

Abstract

Coronary artery calcifications (CACs) are observed in most patients with CKD on dialysis (CKD-5D). CACs frequently progress and are associated with increased risk for cardiovascular events, the major cause of death in these patients. A link between bone and vascular calcification has been shown. This prospective study was designed to identify noninvasive tests for predicting CAC progression, including measurements of bone mineral density (BMD) and novel bone markers in adult patients with CKD-5D. At baseline and after 1 year, patients underwent routine blood tests and measurement of CAC, BMD, and novel serum bone markers. A total of 213 patients received baseline measurements, of whom about 80% had measurable CAC and almost 50% had CAC Agatston scores>400, conferring high risk for cardiovascular events. Independent positive predictors of baseline CAC included coronary artery disease, diabetes, dialysis vintage, fibroblast growth factor-23 concentration, and age, whereas BMD of the spine measured by quantitative computed tomography was an inverse predictor. Hypertension, HDL level, and smoking were not baseline predictors in these patients. Three quarters of 122 patients completing the study had CAC increases at 1 year. Independent risk factors for CAC progression were age, baseline total or whole parathyroid hormone level greater than nine times the normal value, and osteoporosis by t scores. Our results confirm a role for bone in CKD-associated CAC prevalence and progression.

Keywords: coronary calcification; parathyroid hormone; renal osteodystrophy.

Figure 1.

Higher CAC progression in osteoporotic patients. Mean CAC SQRV progression (±SEM) at 1 year in patients with CKD-5D who were osteoporotic and nonosteoporotic stratified by age groups. After adjustment for age, osteoporosis was a significant predictor of CAC progression (β=4.6; 95% CI, 1.8 to 7.5; P=0.002). Osteoporosis was determined by DXA or QCT t scores of the total hip, spine, or femoral neck.

Figure 2.

Higher CAC progression in patients with parathyroid hormone (PTH) levels greater than 450 pg/mL. Mean CAC SQRV progression (±SEM) at 1 year in patients with CKD-5D stratified by baseline whole PTH levels and age. After adjustment for age, whole PTH levels that were nine times higher than normal predicted CAC progression (β=6.9; 95% CI, 2.4 to 11.4; P=0.003). Patients over 65 years of age are not shown because of a low number of patients with high PTH in this age group.