Evaluation of the relationship between Sarcopenia and FRAX score in patients diagnosed with primary osteoporosis

The aim of this study is to evaluate the association between the presence of sarcopenia and dynapenia and the Fracture Risk Assessment Tool (FRAX) score in women diagnosed with primary osteoporosis. This case-control, cross-sectional study included women aged 45–75 years with a diagnosis of primary osteoporosis. Using the International Society of Physical and Rehabilitation Medicine Sarcopenia Group (ISarcoPRM) diagnostic algorithm, sarcopenia, dynapenia, and control groups were formed. Demographic characteristics were recorded, and muscle function was assessed using handgrip strength, the chair stand test, the 6-meter walking test, and the ability to rise from a chair. Ultrasonographic anterior thigh muscle thickness adjusted for body mass index (STAR) was measured. FRAX scores for major osteoporotic and hip fractures were calculated using the FRAX tool adapted for Turkey, and bone mineral density (BMD) parameters were obtained from available dual-energy X-ray absorptiometry (DEXA) scans. FRAX major osteoporotic and hip fracture risks were significantly higher in the sarcopenia and dynapenia groups (p=0.005 and p = 0.003, respectively), both groups had lower handgrip strength (p = 0.001) and slower gait speed (p = 0.004). In the sarcopenia group, the chair stand test duration was longer compared to the other groups (p<0.001), and the STAR value was the lowest (p<0.001). Except for a lower femoral neck T-score in the dynapenia group, BMD values were largely similar across groups (p<0.010). Receiver operating characteristic (ROC) analysis showed that the FRAX threshold values (major fracture≥6.8, hip fracture≥2.0) distinguished sarcopenia and dynapenia from the control group with better sensitivity and specificity. In conclusion, women with primary osteoporosis who had sarcopenia or dynapenia exhibited higher FRAX-predicted major osteoporotic and hip fracture risks, and muscle function was markedly impaired, particularly in the sarcopenia group. These findings suggest that FRAX may contribute not only to fracture risk estimation in osteoporotic patients but also to the identification of sarcopenia.