Cardiovascular autonomic neuropathy (CAN) in patients of type 2 diabetes mellitus: A tertiary care hospital based study

IntroductionDiabetes mellitus (DM) is a clinical syndrome characterized by hyperglycemia due to absolute or relative insulin deficiency. Cardiovascular autonomic neuropathy invokes potentially life threatening outcomes especially in poorly controlled diabetic patients. However, there is scarcity of epidemiological data for CAN in poorly controlled type 2 diabetic patients in Pakistan.ObjectiveThe objective of this study is to assess the frequency of cardiovascular autonomic neuropathy (CAN) in patients with poorly controlled type 2 diabetes mellitus in Pakistan.Study designDescriptive cross-sectional.SettingDepartment of Medicine, Liquate University Hospital, Hyderabad/Jamshoro, Sindh, Pakistan.DurationFebruary to November 2012.Sampling techniqueNon-probability purposive.Material and methodThis study included 207 patients, who all met the inclusion criteria and gave an informed consent for inclusion in the study. All the patients in the study were evaluated for CAN using four different clinical tests- Resting heart rate, test for orthostatic hypotension, hand gripping test and QTc interval on ECG. Resting Heart Rate of more than 100 beats per minute was taken as abnormal. Orthostatic hypotension was defined as a fall of systolic blood pressure >20 mmHg and/or diastolic blood pressure >10 mmHg on change of posture. The patients were asked to squeeze a small ball in hand gripping test and an increase in diastolic blood pressure <15 mmHg was considered abnormal. ECG recording with QTc interval >440 ms was considered abnormal or prolonged. Patients were labeled as CAN +ve if any two or more than two of the above listed tests were found positive/abnormal.ResultsIn our study, 76 out of 207 (36.7%) of the patients with poorly controlled type 2 diabetes mellitus were found to have cardiovascular autonomic neuropathy (CAN).ConclusionCardiac autonomic dysfunctions are common in poorly controlled type 2 diabetes.