Trabecular bone score may improve FRAXA® prediction accuracy for major osteoporotic fractures in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Cohort Study

ASummary FRAXA (R) is widely used to evaluate fracture risk of individuals in clinical settings. However, FRAXA (R) prediction accuracy is not sufficient, and improvement is desired. Trabecular bone score, a bone microarchitecture index, may improve FRAXA (R) prediction accuracy for major osteoporotic fractures in community-dwelling elderly Japanese men. Introduction To improve fracture risk assessment in clinical settings, we evaluated whether the combination of FRAXA (R) and Trabecular Bone Score (TBS) improves the prediction accuracy of major osteoporotic fractures (MOFs) in elderly Japanese men compared to FRAXA (R) alone. Methods Two thousand and twelve community-dwelling men aged a parts per thousand yen65 years completed the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Baseline Study comprising lumbar spine (LS) and femoral neck areal bone mineral density (aBMD) measurements, and interviews regarding clinical risk factors required to estimate 10-year risk of MOF (hip, spine, distal forearm, and proximal humerus) using the Japanese version of FRAXA (R) (v.3.8). TBS was calculated for the same vertebrae used for LS-aBMD with TBS iNsight software (v.2.1). MOFs that occurred during the follow-up period were identified by interviews or mail and telephone surveys. Prediction accuracy of a logistic model combining FRAXA (R) score and TBS compared to FRAXA (R) alone was evaluated by area under receiver-operating characteristic curves (AUCs), as well as category-free integrated discrimination improvement (IDI) and net reclassification improvement (NRI). Results We identified 22 men with MOFs during 8140 person-years (PY) of follow-up among 1872 men; 67 men who suffered from fractures other than MOFs were excluded. Participants with MOFs had significantly lower TBS (p = 0.0015) and higher FRAXA (R) scores (p = 0.0089) than those without. IDI and NRI showed significant improvements in reclassification accuracy using FRAXA (R) plus TBS compared to FRAXA (R) alone (IDI 0.006 (p = 0.0362), NRI 0.452 (p = 0.0351)), although no difference was observed in AUCs between the two. Conclusions TBS may improve MOF prediction accuracy of FRAXA (R) for community-dwelling elderly Japanese men.