T-Score Discordance Between Hip and Spine in Diagnosis of Osteoporosis in Patients From Iranian Population

Today, osteoporosis is a major healthcare system problem globally. Each year, osteoporosis leads to more than 8.9 million fractures. In practice, osteoporosis can be diagnosed following a low-energy trauma fragility fracture of a bone or by a bone mineral density measurement using dual X-ray absorptiometry showing a T-score of ≤-2.5. This is a retrospective study that reviewed all subjects with osteoporosis or osteopenia indication, which were referred by practitioners for diagnostic densitometric evaluation to Alzahra hospital in Isfahan, Iran. from January 1, 2017, to December 31, 2019. Bone mineral density (BMD) reports were reviewed to identify all cases of osteoporosis or osteopenia. Our data analysis according to the World Health Organization (WHO) diagnostic classification showed that simultaneously measured T-scores at the spine and hip are concordant in 49.60% of patients and discordant by at least one diagnostic class in 49.95%. There was no significant discordance prevalence when one site was osteoporotic, and another site was normal (The prevalence was only 4.74%). Major T-score discordance was directly correlated to age (r=0.908, P=0.005), but there was no statistical relationship between minor T-score discordance and age (P=0.07). Clinicians should expect that at least half of patients tested by DXA will demonstrate T-score discordance between spine and total hip measurement sites. However, discordance is a real finding, and clinicians should be familiar with this issue and adopt specific strategies for these patients to investigate the cause or causes of the discordance.