The new concept of dynapenic Skeletal Muscle Function Deficit in the assessment of osteoporotic patients

Background. Recent studies demonstrated a significant association between sarcopenia and severe osteoporosis in older women. However, the decline in muscle performance and mobility limitation are due only in part to the age-related reduction of muscle mass. The aim of our study was to evaluate the impact of dynapenic skeletal muscle function deficit (SMFD) on bone fragility in osteoporotic women. Materials and methods. In this retrospective study, we analyzed data derived from the medical record of postmenopausal women aged 55 or older referring to an outpatient rehabilitation service. In our population, we defined dynapenic SMFD according to the Foundation for the National Institutes of Health’s (FNIH) criteria, based on reduction of gait speed(<0.8 m/s), handgrip strength (<16 kg), and normal appendicular lean mass adjusted for body mass index (>0.512). We analyzed the Vertebral Fracture Assessment (VFA) from DXA spine images to identify vertebral fragility fractures. Results. Results are showed in table. In our cohort, for a woman with dynapenic SMFD the odds ratio (OR) adjusted for age for vertebral fragility fracture was 1.79 (95%CI = 1.40-3.68; p= 0.044). Population (n=70) Non-dynapenic SMFD (n= 45) Dynapenic SMFD (n= 25) p-value Age 67 ± 7.71 64.73 ± 1.10 71.08 ± 1.34 <0.001 BMI (kg/m2) 25.21 ± 3.34 25.13 ± 0.52 25.34 ± 0.64 0.80 Falls (n) 13 (18.57%) 8 (17.78%) 5 (20%) 0.82 VFx (n) 36 (51.43%) 17 (37.78%) 19 (76%) 0.002 BMD L1-L4 (g/cm2) 0.893 ±0.203 0.871 ± 0.031 0.934 ± 0.038 0.23 Note: data are expressed as mean ± SD Abbreviations: BMI= body mass index; VFx= vertebral fragility fractures; BMD= Bone Mineral Density; SMFD= Skeletal Muscle Function Deficit. Conclusions. In our opinion, the concept of dynapenic SMFD could be useful to provide a comprehensive assessment of the risk fracture in osteoporotic patients