Determining the Relative Frequency of Bone Mineral Densitometry (BMD) Discordance and its Related Factors in the Spine-Femur Regions Using the DEXA Method

Osteoporosis is the most prevalent bone metabolic disease, which is diagnosed by the DEXA method. T-score discordance is noted by measuring DEXA in two different regions of the spine and the pelvis. Discordance occurs when the result of bone mineral densitometry between two regions falls under two different diagnostic classes, defined by the World Health Organization's classification system. Discordance is defined when two measured regions fall under a diagnostic class. Minor discordance denotes the difference between two regions in a diagnostic class, while major discordance refers to an osteoporosis region and a normal region. The present study aimed to determine the prevalence of discordance and related factors among patients with osteoporosis. This descriptive-analytical study was cross-sectional and involved 383 patients (339 women and 44 men) with an average age of 57.07±12.57. Data required were collected following the conduct of interviews, clinical examinations, and the analysis of bone mineral densitometry. Data were analyzed by SPSS software (version 13). Based on results, 53.8% of the subjects showed T-score discordance, while 49.89 and 3.91% were subjected to minor and major discordance, respectively. Higher ages were also found to affect discordance, while smoking served as a protective factor. Study showed that age had significant positive correlation with major discordance. In our study, an increase in age increased T-score discordance, whereas smoking increased the T-score concordance of two regions measured in osteopenia and osteoporosis classes because of causing bone resorption (osteoporosis) in both types of cortical and trabecular bones; meanwhile, the creation of discordance held a protective effect. Other causes had no effect in creating T-score discordance.