A single yearly dose of zoledronic acid had no impact on the progression of abdominal aortic calcification in postmenopausal women with osteoporosis, based on data from 502 women.
Although bisphosphonates have been shown to reduce the formation and progression of vascular calcification in animal studies, the impact on aortic calcification in humans has not been studied, wrote Guoqi Cai, PhD, of the University of Tasmania, Australia, and colleagues.
In a post hoc analysis published in Osteoporosis International, the researchers reviewed data from the HORIZON Pivotal Fracture trial of women with osteoporosis.
The study population included 234 postmenopausal women with osteoporosis who received an annual infusion of 5 mg zoledronic acid (ZA) and 268 who received a placebo. The mean age of the women was 72.5 years. Overall, abdominal aortic calcification (AAC) was present in 292 women (58%) at baseline, defined as an AAC score greater than 0, and AAC scores were similar between the intervention and placebo groups.
Over 3 years, AAC progressed similarly between the ZA and placebo groups (29% and 31%, respectively). Progression was defined as an increase in AAC score, which was measured by comparing spinal x-rays at baseline and after 3 years. In a subgroup analysis, progression of AAC was similar between the ZA and placebo groups with and without baseline AAC.
“The lack of effect on the progression of vascular calcification with zoledronic acid treatment in this study does not rule out a potential role of bisphosphonates in reducing cardiovascular mortality mediated through other mechanisms,” the researchers noted.
No correlation appeared between change in AAC score and change in bone mineral density at the total hip and femoral neck during the study period in any of the groups.
The study findings were limited by several factors including the post hoc analysis, potential lack of sensitivity of the AAC-8 scale in measuring small AAC changes, and homogenous study population, the researchers noted.
However, the study is the first to examine the impact of zoledronic acid on aortic calcification in humans, and was strengthened by the randomized design, the researchers said. Although other studies on the impact of bisphosphonates on vascular calcification have been inconsistent, the “finding that zoledronic acid was not protective against vascular calcification agrees with previous trials of nitrogen-containing bisphosphonates conducted in postmenopausal women with osteoporosis,” as well as chronic kidney disease patients and renal transplant patients, they said.
“Thus, our findings do not support the use of zoledronic acid for the treatment of vascular calcification,” they concluded.
The study was supported by Novartis. Dr. Cai had no financial conflicts to disclose.
SOURCE: Cai G. et al. Osteoporosis Int. 2020 May 2. doi: 10.1007/s00198-020-05430-z.