Diagnosis of Presarcopenia Using Body Height and Arm Span for Postmenopausal Osteoporosis

Sarcopenia and osteoporosis are both serious health problems in postmenopausal women. The Asia Working Group for Sarcopenia recommends using the skeletal muscle index (SMI), which is height-adjusted appendicular skeletal muscle mass (ASMM). However, loss of height has been shown to be a common clinical finding in patients with osteoporosis. This study examined the prevalence of presarcopenia using height and arm span, which is a predictor of height, and investigated the diagnostic accuracy for presarcopenia.

A total of 55 post-menopausal osteoporotic patients aged 62-95 years underwent bioelectrical impedance analysis (BIA) for ASMM measurement and dual-energy X-ray absorptiometry (DXA) scan for bone mineral density (BMD). Anthropometric measurements, including height, weight, and arm span were taken, and body mass index (BMI), SMI, and arm span-adjusted SMI (Arm span SMI) were calculated. Presarcopenia was defined as SMI or Arm span SMI <5.7 kg/m² in this study.

The prevalence of presarcopenia was 27.3% and 38.2% evaluated by SMI and Arm span SMI, respectively. The prevalence of presarcopenia was higher when evaluated by Arm span SMI than by SMI. In the presarcopenia group diagnosed only by Arm span SMI (n=11), the arm span-height difference was significantly higher (p<0.001) and the percentage of young adult mean (YAM) femoral neck-BMD was significantly lower (p=0.013) compared to the normal group diagnosed by both SMI and Arm span-SMI (n=29).

These results indicated that Arm span SMI might be useful for the diagnosis of sarcopenia in patients with severe osteoporosis and kyphosis.