Pattern and prevalence of cardiovascular autonomic neuropathy in diabetics visiting a tertiary care referral center in India.

The cardiovascular autonomic neuropathy (CAN) is a known complication of long standing diabetes. In the present study, the prevalence of sympathetic and parasympathetic abnormalities in diabetic patients was evaluated on retrospective analysis of standard tests done for the assessment of CAN. Three different scoring systems were utilized for assessment of CAN namely, Ewing's crtieria, Bellavere's criteria and the criteria followed at the Autonomic Function Test laboratory. All the three criteria use different set of tests for classification. A total of 124 patients' laboratory data was analysed. The abnormality of single test ranged from 6.49% in Valsalva Maneuver to 47.41% in cold pressor test. When Bellavere's criteria was used only 53 patients had evidence of CAN while Ewing's criteria revealed that 100 patients had CAN however 69 of these patients could not be categorized. The criteria used by AFT laboratory revealed that isolated sympathetic (49 patients) and paraysmpathetic (10 patients) abnormality can be seen in CAN along with those with combined deficits (42 patients). If the Bellavere's criteria is used then patients with dominant sympathetic neuropathy are likely to be missed during testing. High prevalence of CAN in tertiary care referral centre suggests that the testing of autonomic functions in diabetics should be done routinely. It is recommended that full battery of test to evaluate both the arms of autonomic drive namely sympathetic and parasympathetic should be done and reported as such.