Cardiac parasympathetic function in different class interval of age in type 2 diabetes mellitus

Reduced sinus arrhythmia indicates diabetic autonomic neuropathy. Amplitude of respiratory sinus arrhythmia declines with aging. But no studies found on sinus arrhythmia in relation to different class interval of age in diabetes. To compare the Expiratory: Inspiratory ratio of patients with diabetes in different class interval of age with controls. In 207 patients with diabetes mellitus and 392 controls, expiratory: inspiratory ratio was obtained while breathing at 6 respiratory cycles per minute connected to limb lead II of electrocardiogram. Study and control subjects were divided into 5 subgroups with 10 years class interval (CI) as follows: CI 1: ≤ 40; CI 2: 41-50; CI 3: 51- 60; CI 4: 61-70 and CI 5: 71-80 years. In study subjects frequency of diabetes related complications in different class interval of age was noted. Statistical analysis included unpaired t, Mann-Whitney U, Chi-square, Kruskal -Wallis, and Dunn's Multiple Comparisons tests. Statistical significance was considered at p < 0.05. Expiratory: Inspiratory ratio was lower in study subjects in CI 2, 3, 4 and 5 compared to corresponding controls (p < 0.001). There was no difference in Expiratory: Inspiratory ratio between study subjects and controls in CI 1. In study group frequency of hypertension, stable angina and somatic neuropathy was higher with aging (p < 0.0001). Expiratory: Inspiratory ratio is lower in patients with diabetes mellitus after 40 years of age. Somatic neuropathy, hypertension and stable angina increases with aging.