Bone mineral density of extremities is associated with coronary calcification and biopsy-verified vascular calcification in living-donor renal transplant recipients

Abstract

Chronic kidney disease (CKD) mineral and bone disorders (CKD-MBD) may lead to low bone mineral density (BMD) and vascular calcification (VC), but links to the latter are unclear. Here we investigated associations between BMD, coronary artery calcium (CAC) scores, and histological signs of VC in end-stage renal disease (ESRD) patients undergoing living-donor kidney transplantation (LD-Rtx). In 66 ESRD patients (median age 45 years, 68% males), BMD (by dual-energy X-ray absorptiometry, DXA), CAC score (by computed tomography, CT; n = 54), and degree of VC score (graded by histological examination of epigastric artery specimens collected at LD-Rtx; n = 55) were assessed at the time of LD-Rtx. Of the patients, 26% had osteopenia and 7% had osteoporosis. Of those undergoing artery biopsy, 16% had extensive VC, and of those undergoing CT 28% had high CAC score (>100 Agatston units). CAC scores correlated with BMD of legs and pelvis. BMDs of leg and pelvic sub-regions were significantly lower in patients with extensive VC. In multivariate regression analysis adjusted for age and gender, lower BMD of leg sub-region was associated with CAC score >100 AUs and extensive VC, and patients with extensive VC had significantly higher CAC score. Both high CAC and extensive VC were independently predicted by low BMD of legs. Low BMD has the potential to identify ESRD patients at risk of vascular calcification.

Keywords: Bone mineral density; Coronary artery calcium; End-stage renal disease; Living-donor renal transplant recipients; Vascular calcification.