Introduction
Anti-resorptive medications are first-line treatments for osteoporosis. Additionally, patients with osteoporosis are at high cardiovascular risk, partly due to vascular calcification, such as in the coronary vessels. It is uncertain if the presence of coronary artery calcification (CAC) effects bone mineral density (BMD) response to anti-resorptive treatment. We therefore assessed changes in BMD following initiation of anti-resorptive treatment for osteoporosis in patients with and without evidence of CAC.
Methods
Individuals dispensed at least one prescription for an anti-resorptive medication (bisphosphonates or denosumab) at Monash Health between 2009-2022 were identified. Unique record numbers for these individuals were then cross-matched against the cardiac CT imaging service at Monash Heart (HREC#73603). CAC was detected by CT coronary angiogram (CTCA). We included only those patients having a baseline BMD measurement within two years of CTCA. The annualised percentage change in femoral neck BMD was calculated and adjusted for age, sex, height, weight, and number of years on anti-resorptive treatment.
Results
106 individuals were identified of which 85 (women=70 [85%], median age=73 years [interquartile range 64-79 years]) had a follow-up BMD measurement including 19 with, and 66 without, evidence of CAC. Those with CAC were older (76 years versus 64 years, p<0.001). There were 70 bisphosphonate users and 15 denosumab users. Individuals with evidence of CAC experienced, on average, a 1.2% lower increase [(0.345% (0.343 to 0.348) versus -0.881% (-0.883 to -0.879), mean difference -1.226% (-1.493 to -0.959; p<0.05)] in annualised femoral neck BMD with anti-resorptive therapy after adjusting for important clinical risk factors.
Interpretation
These preliminary data suggest that CTCA-determined CAC may negatively impact femoral neck BMD increases with anti-resorptive therapy. Analysis of the full cohort is presently underway.