Study On Heart Rate Variability And Its Circadian Rhythm In Type 2 Diabetes With Lower Extremity Neuropathy

Objective:Diabetes mellitus is a kind of chronic disease with hyperglycemia. Diabetic peripheral neuropathy and diabetic autonomic neuropathy are the causes of morbidity and mortality in type 2 diabetes. The early diagnosis and treatment of diabetic autonomic neuropathy are difficult for the complexity and variability of its clinical manifestation, as well as the inconsistency of its detecting methods and diagnosing standards. As a stable, reliable, sensitive and non-invasive method, heart rate variability(HRV) analysis and circadian rhythm(CR) of HRV could be used for the evaluation of autonomic nervous function. Electroneuromyogram is a sensitive method for the diagnosis of early lower extremity neuropathy in diabetes. The present study is to test the possibility of HRV and it's CR analysis being used in detecting lower extremity neuropathy in type 2 diabetes. Then the results of HRV were correlated to nerve conduction velocity.We hope it can provide assistance for autonomic nervous function of type 2 diabetes with lower extremity neuropathy.Methods:117 type 2 diabetic subjects were divided into two groups:group with lower extremity neuropathy (DM 2 group, n=58) and group without lower extremity neuropathy (DM 1 group, n=59).50 control subjects were recruited in the study. HRV and its CR were determined from 24-hour Holter recording. Subjects from DM group were conducted electroneuromyography.Result:1 There was no difference within the three groups in age, gender, body mass index, systolic blood pressure, diastolic blood pressure,pulse pressure and blood lipid levels.2 There were significant difference in timing domain parameter of HRV among control subjects, DM 1 and DM 2.Compared with DM 1 group, SDNN,SDANN and SDNNIDX decreased significantly in DM 2 group (P<0.05) 3 There were significant difference in frequency domain parameter of HRV among control subjects, DM 1 and DM 2. Compared with DM 1 group, TP,VLF and LF decreased significantly in DM 2 group (P<0.05)4 SDNN,SDANN,SDNNIDX,rMSSD,pNN50 were positively correlated to TP, VLF,LF,HF respectively. SDANN,rMSSD,pNN50 were positively correlated to LF/HF.5 CR of HRV in control group was decreased in daytime and increased in nighttime, but LF,LF/HF,SDNN was increased in daytime and decreased in nighttime. CR of HRV were changed in DM 1 and disappeared in DM 2.6 Timing domain parameter and frequency domain parameter of HRV were positively correlated to nerve conduction velocityConclusion:Decrease of HRV, changed and disappeared of CR showed damage of vegetative nervous in type 2 diabetes and more significant damage of vegetative nervous in type 2 diabetes with lower extremity neuropathy. It showed correlation in diabetic autonomic neuropathy and diabetic lower extremity neuropathy that HRV was correlated to nerve conduction velocity. HRV can provide assistance in assessing autonomic nervous function of type 2 diabetes and type 2 diabetes with lower extremity neuropathy in early stages.