Prediction of Fractures and CV Events With Serum Osteoprotegerin Levels

Osteoporotic fractures and cardiovascular (CV) disease often coexist. Although patients with CV disease have a higher risk for fracture, and those with fractures have a higher risk for CV disease, data on shared risk factors are scarce. The investigators of the current analysis, published in the Journal of Bone and Mineral Research, sought to evaluate the association of serum osteoprotegerin (OPG) levels with the risk for fractures and CV outcomes (acute coronary syndrome [ACS], cardiac death) in older men.

The Structure of the Aging Men’s Bones (STRAMBO) study is a single-center, prospective, community-based cohort study of bone fragility in men. A total of 819 home-dwelling men, 60 to 87 years of age, were followed prospectively for 8 years. Serum OPG was assessed at baseline by enzyme-linked immunosorbent assay. Bone mineral density (BMD) at femoral neck and trabecular bone score (TBS) were measured by dual-energy X-ray absorptiometry (DXA) scans. Clinical risk factors and the Fracture Risk Assessment Tool (FRAX) were also assessed. Incident vertebral fractures were evaluated on lateral DXA scans after 4 years and 8 years. Continuous and class variables were compared by OPG quartiles (Q1 [lowest] to Q4 [highest]).

Following adjustment for FRAX corrected for femoral neck BMD and TBS, diabetes, ischemic heart disease, and prior falls, the risk for fracture was 2-fold higher in the highest vs the lowest OPG quartile (hazard ratio [HR], 2.35; 95% CI, 1.35-4.10). The risk for vertebral and nonvertebral fractures was higher in the highest vs lowest OPG quartile (odds ratio [OR], 2.76; 95% CI, 1.08-7.05 and HR, 2.46; 95% CI, 1.23-4.92). The risk for major osteoporotic fracture was higher in the fourth vs first OPG quartile (HR, 2.43; 95% CI, 1.16-5.10).

The risk for CV outcomes (adjusted for confounders) was higher in the highest vs lowest OPG quartile (HR, 3.93; 95% CI, 1.54-10.04). The risk for fracture and CV outcomes was higher in the highest OPG quartile vs the lower quartiles combined (HR, 2.06; 95% CI, 1.35-3.14 and HR, 2.98; 95% CI, 1.60-5.54, respectively).

The investigators concluded that, in older men, high serum OPG levels are associated with a higher risk for fragility fracture and CV outcomes, including acute coronary syndrome and cardiac death, after adjusting for cofounders.

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Reference

Szulc P, Chapurlat R, Hofbauer LC. Prediction of fractures and major cardiovascular events in men using serum osteoprotegerin levels: the prospective STRAMBO study [published online July 4, 2017]. J Bone Miner Res. doi:10.1002/jbmr.3213