Endocrine Abstracts

Purpose: The purpose of this study was to evaluate the prevalence and characteristics of individuals with spine–femur bone mineral density (BMD) discordance and to examine whether trabecular bone score (TBS) is associated with major and minor BMD discordance in postmenopausal women.

Methods: This retrospective study included 533 healthy postmenopausal women (median age, 60 years; range, 55–82 years) who visited our hospital for a health check-up and performed dual X-ray absorptiometry for the evaluation of BMD between May 2013 and April 2017. Major discordance is defined when the T-score at one site indicates osteoporosis and at the other site indicates normal BMD. Minor discordance refers to one degree of difference in the diagnosis between two sites. The differences were analyzed using the Kruskal-Wallis test.

Results: Two hundred and forty-six participants (48.2%) exhibited spine-femur BMD discordance. Major discordance was noted in 4.5% (n=24) of the study population, and these patients were all diagnosed with osteoporosis in the lumbar spine. Minor discordance was noted in 41.7% (n=222) of the study population. In the group with normal BMD of the lumbar spine, the participants in the discordance group showed significantly lower TBS (median, 1.364; interquartile range [IQR], 1.328–1.398) than that in the concordance group (median, 1.406; IQR, 1.358–1.439). The participants with discordance who showed normal (median, 1.357; IQR, 1.326–1.399) or osteopenic (median, 1.352; IQR, 1.313–1.387, P<0.001) BMD in the femur had significantly lower TBS compared with that in the concordance group (for normal BMD; median, 1.406; IQR, 1.1.358–1.439; for osteopenic BMD, median, 1.364; IQR, 1.328–1.398, P<0.001). The major discordance group exhibited the lowest TBS in both groups with normal (median, 1.331; IQR, 1.275–1.384) and osteopenic (median, 1.307; IQR, 1.245–1.345) femoral BMD. The groups with osteoporotic femur or both osteopenic and osteoporotic lumbar spine did show a significant difference in TBS regardless of the presence of discordance.

Conclusions: The high prevalence of discordance between the spine and the femur in terms of BMD may be associated with degraded microarchitecture, especially in the presence of normal or osteopenic BMD, and suggests the need for further risk assessment and management in such patients.