Autonomic nervous system function in type 2 diabetes using conventional clinical autonomic tests, heart rate and blood pressure variability measures

BACKGROUND: There are currently approximately 40.9 million patients with diabetes mellitus in India and this number is expected to rise to about 69.9 million by the year 2025. This high burden of diabetes is likely to be associated with an increase in associated complications. MATERIALS AND METHODS: A total of 23 (15 male and 8 female) patients with type 2 diabetes of 10-15 years duration and their age and gender matched controls (n=23) were recruited. All subjects underwent detailed clinical proforma, questionnaire related to autonomic symptoms, anthropometry, peripheral neural examination and tests of autonomic nervous system including both conventional and newer methods (heart rate and blood pressure variability). RESULTS: Conventional tests of cardiac parasympathetic and sympathetic activity were significantly lower in patients with diabetes compared to the controls (P<0.05). The diabetic patients group had significantly lower high frequency and low-frequency HRV when expressed in absolute units (P<0.05) and total power (P<0.01) compared to the controls. CONCLUSION: Data from the current study demonstrated that diabetics had both cardiac sympathetic and cardiac parasympathetic nervous system involvement. The presence of symptoms and involvement of both components of the autonomic nervous system suggest that dysfunction has been present for a while in these diabetics. There is a strong need for earlier and regular evaluation of autonomic nervous system in type 2 diabetics to prevent further complications.