Skeletal muscle mass is associated with glycemic variability in patients with ST-segment elevation myocardial infarction

Skeletal muscle function has been studied to determine its effect on glucose metabolism; however, its effect on glycemic variability (GV), which is a significant glycemic marker in patients with coronary artery disease, is unknown. The aim of the present study was to elucidate the association between skeletal muscle mass and GV. Two hundred and eight consecutive ST-segment elevation myocardial infarction (STEMI) patients who underwent continuous glucose monitoring to evaluate mean amplitude of glycemic excursion (MAGE) as GV and a dual-energy X-ray absorptiometry (DEXA) to evaluate skeletal muscle mass were enrolled. Skeletal muscle index (SMI) level was calculated as skeletal muscle mass divided by height squared (kg/m(2)). SMI level in men had a weak inverse correlation with Log MAGE level by the linear regression model in diabetes mellitus (DM) patients (R-2 = 0.139, P = 0.004) and even in non-DM patients (R-2 = 0.068, P = 0.004). Multivariate linear regression analysis with a stepwise algorithm (age, male sex, body mass index [BMI], hemoglobin A1c [HbA1c], fasting glucose, HOMA-IR, and SMI; R-2 = 0.203, P < 0.001) demonstrated that HbA1c level (B = 0.077, P < 0.001) and SMI level (B = - 0.062, P < 0.001) were both independently associated with Log MAGE level. This association was also confirmed in limited non-DM patients with a subgroup analysis. SMI level was associated with Log MAGE level (B = - 0.055, P = 0.001) independent of BMI or HbA1c level. SMI level was inversely associated with MAGE level independent of glucose metabolism in STEMI patients, suggesting the significance of skeletal muscle mass as blood glucose storage for glucose homeostasis to reduce GV.