Abstract: Objective To explore the glycemic variability (GV) and the relationship between mean amplitude of glycemic excursion (MAGE) and cardiac function in the elderly patients with type 2 diabetes mellitus(T2DM). Methods A total of 48 elderly T2DM patients treated in Geriatric Comprehensive Department in Xuanwu Hospital, Capital Medical University in 2019 were enrolled in this study, and the levels of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), glycated albumin (GA) were measured. The patients were divided into the HbA1c standard group (HbA1c<6.5%, n=16) and the HbA1c substandard group (HbA1c≥6.5%, n=32). Each patient received a 3-day continuous glucose monitoring (CGM) to obtain the blood glucose parameters including mean blood glucose (MBG), MAGE, standard deviations of blood glucose (SDBG), largest amplitude of glycemic excursion (LAGE), coefficient of variation (CV) and glucose target time in range (TIR), target time above range (TAR) and target time below range (TBR), and then the patients were divided into the MAGE standard group (MAGE<3.9 mmol/L, n=22) and the MAGE substandard group (MAGE≥3.9 mmol/L, n=26). Each patient underwent echocardiography detection to obtain the cardiac function indicators including left ventricular ejection fraction (LVEF), stroke volume (SV), end-systolic volume (EDV) and cardiac output (CO). The level of GV was compared between the HbA1c standard group and the HbA1c substandard group. The correlation between MAGE and cardiac function in the elderly T2DM patients was analyzed. Results Compared with the HbA1c substandard group, the substandard rate of FPG, SDBG, TIR, TAR and the duration of T2DM were lower, and substandard rate of TBR was higher in the HbA1c standard group (P<0.05 or P<0.01). Compared with the MAGE substandard group, the levels of SDBG, LAGE and CV were lower, and the levels of TIR, CO and LVEF were higher in the MAGE standard group (P<0.05 or P<0.01). Pearson correlation analysis showed that MAGE was negatively correlated with CO and LVEF (r=-0.340, -0.319; P=0.018, 0.027, respectively). Conclusions The elderly T2DM patients who reach standard HbA1c range still have the problem of GV, and have the risk of hypoglycemia. MAGE is related to the heart function of the elderly patients with T2DM, and the glucose indexes should be comprehensively monitored and GV should be improved in time to prevent and control heart diseases.

Key words: type 2 diabetes mellitus, glycemic variability, mean amplitude of glycemic excursion, cardiac function, aged