Impact of glycemic control over cardiac autonomic neuropathy

Cardiovascular autonomic neuropathy (CAN) is one of the most common and serious complications associated with diabetes and is defined as the impairment of the autonomic control of the cardiovascular system, whose prevalence in Indian population has been reported to be > 50%. The risk factors associated with CAN include hyperglycemia, duration of diabetes, hypertension, dyslipidemia, and obesity. This study was conducted to examine the association of CAN with its determinants among diabetics.

Socio-demographic characteristics were noted alongwith performance of biochemical analyses of blood samples according to standard hospital pathology laboratory protocols. Clinical assessment of CAN comprised a of 5 indexes, including 3 heart rate variability parameters (resting tachycardia, Qtc interval > 440 msec, exercise intolerance) and 2 blood pressure parameters (orthostatic hypotension, abnormal hand gripping test).

The odds of CAN increased with poor glycemic control (FBS ≥ 126 mg/dL (OR = 1.17 (1.02-10.68); 2 hr PPBS ≥ 200 mg/dL (OR 1.63 (1.26-8.82) and HbA1c ≥ 6.5% (OR = 10.68 (1.54-208.02). Significant difference was also found in relation to duration of diabetes, weight and body mass index of the participants with various grades of CAN.

CAN is associated strongly with poor glycemic control. Obesity seems to be involved in the impairments of the cardiac autonomic function and this factor must therefore be taken into account in future studies when interpreting the results. Body mass control and glycemic control could provide an important approach to reducing CAN.