Low skeletal muscle mass is associated with the risk of all-cause mortality in patients with type 2 diabetes mellitus

Background: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of muscle mass reduction. However, the association between muscle mass and mortality in T2DM remains unknown. Methods: This was a historical cohort study with the endpoint of all-cause mortality. This study included 163 Japanese men and 141 postmenopausal women with T2DM whose body compositions were evaluated using dual-energy X-ray absorptiometry. Low muscle mass was defined as a skeletal muscle mass index (SMI) of <7.0 kg/m 2 for men and <5.4 kg/m 2 for women. Results: During the 6-year follow-up period, 32 men and 14 women died. In a Cox regression analysis adjusted for age, T2DM duration, glycated hemoglobin, serum creatinine, fasting C-peptide, body mass index, and lean body mass were associated with the risk of mortality in men [hazard ratio (HR) = 1.81, 95% confidence interval (CI) = 1.00–3.28 per standard deviation (SD) decrease, p = 0.049] and women (HR = 4.53, 95% CI = 1.14–17.96 per SD decrease, p = 0.032). Neither fat mass nor bone mineral content was associated with mortality. Low SMI was associated with increased mortality in women (HR = 5.97, 95% CI = 1.04–34.37, p = 0.045), while the association between low SMI and mortality was marginal in men (HR = 2.38, 95% CI = 0.92–6.14, p = 0.074). Conclusions: Low muscle mass was independently associated with all-cause mortality in patients with T2DM. The preservation of skeletal muscle mass is important to protect patients with T2DM from increased mortality risk.