Heart rate variability in the Kirgiz and Han Chinese patients with type 2 diabetes mellitus

Abstract

Objective To investigate the relationship between heart rate variability and type 2 diabetes mellitus(T2DM) in Kirgiz and Han, to understand the differences between ethnic groups, at the same time to provide effective method for type 2 diabetic autonomic neuropathy. Methods 24-h Holter recording was performed in 146 individuals.75 cases of T2DM confirmed by glycolated hemoglobin(HbA1c) were selected as observation group, Kirgiz 40 people, Han 35 people.While 71 subjects without T2DM were chosen as control group, Kirgiz 34 people, Han 37 people.The HRV indices, including standard deviation(SD) for the time between normal-to-normal complexes in the entire 24 h electrocardiographic recording(SDNN), the average of SD for the time between normal-to-normal intervals for each 5 min period(SDNN5), the percentage of adjacent RR intervals 50 ms apart(PNN50), normal RR intervals divided by RR intervals derived from the triangle index(TRIA), SD of the average normal-to-normal intervals for each 5 min period (SDANN) and root-mean square of differences of successive RR intervals (RMSSD) were compared between these groups. Results There were no significant differences in age, gender, education level and smoking between Kirgiz and Han patients.The differences were statistically significant in SDNN, SDNN5, PNN50, SDANN, TRIA(t=3.392, P=0.001; t=3.652, P=0.001; t=3.826, P=0.001; t=3.235, P=0.002; t=2.378, P=0.02) between patients with or without T2DM in Kirgiz population.In contrast, the mean square root of SDNN, SDNN5, PNN50, TRIA, RMSSD(t=3.498, P=0.001; t=3.414, P=0.001; t=2.105, P=0.039; t=2.102, P=0.039; t=3.413, P=0.001) were statistically significant in Han population between T2DM patients and nondiabetic patients.There was no deference between Han and Kirgiz patients without T2DM in HRV, whereas the TRIA(t=2.887, P=0.005) had significant difference in T2DM patients between Han and Kirgiz population. Conclusion The HRV is significantly reduced in the T2DM patients, especially the Kirgiz.The HRV analysis using 24h Holter is a noninvasive technology to detect the T2DM. Key words: Diabetes mellitus, type 2; Heart rate variability; Electrocardiography, ambulatory; Kirgiz; Han