Relationship Between Heart Rate Variability And Peripheral Vascular Disease In Type 2 Diabetic Patients

OBJECTIVE AND BACKGROUNDType 2 diabetes mellitus (T2DM) represents a high risk condition for the development of arteriosclerosis in the lower extremities which make major contributions to diabetic mortality and morbidity. In type 2 diabetic patients, it is testified that hyperglycemia, hypercholesterolemia, hyperinsulinemia and endothelium dysfunction are main risk factors for peripheral vascular arteriosclerosis. Diabetic autonomic neuropathy (DAN) often coexists with other chronic diabetic complications for the same pathogenesis. Heart rate variability( HRV) has been proved to be a sensitive and no-invasive method for diagnosis of DAN. Several studies found HRV to be decreased in type 2 diabetic patients with autonomic neuropathy, but very few studies were involved in the relationship between HRV and peripheral vascular disease. Our study was aimed to analyze HRV and investigate the relationship between HRV and peripheral vascular disease in type 2 diabetic patients. RESEARCH DESIGN AND METHODSA total of 135 patients with T2DM and 20 normal controls were included in our study. The T2DM patients were divided into two groups based on Doppler Uitrasonic examination: 67 patients withoutperipheral vascular disease and 68 patients with peripheral vascular disease (50 in minor peripheral vascular disease group and 18 in medium peripheral vascular disease group). The parameters of HRV both in the patients and controls (SDNN, SDANN, RMSSD, PNN50 SDNNind and LF/HF) were evaluated by 24-hours dynamic electrocardiogram. Body mass index (BMI), blood pressure (BP),Triglyceride(TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) , fast blood sugar(FBS), fast C-peptide(C-P), fast insulin(FINS), serum creatinine(SCr), urinary albumin excretion(UAE), creatinine clearance(CCr) and glycated hemoglobin Ale(HbAic)were also examined. RESULTS:l.The levels of FBS, TG, TC in type 2 diabetic patients were significantly higher than those in normal controls (P<0. 01 or p<0. 001 ). T2DM pateints with peripheral vascular disease had higher TG, SCr, UAE, TC and lower CCr, HDL-C than T2DM pateints without peripheral vascular disease.2. The SDNN, SDANN, RMSSD, PNN50, and SDNNind in type 2 diabetic patients were ignificantly lower than those in normal controls (P<0. 01 or p<0. 001 ).3. The reduced HRV was associated with the severity of peripheral vascular disease in T2DM patients.The patients with minor peripheral vascular disease had lower SDNN, SDANN, SDNNind and PNN50 than the patients without peripheral vascular disease ( P <0. 01 or p<0. 001). Further more, the patients with medium peripheral vascular disease had the lowest SDNN, SDANN, LF/HF and SDNNind compared to the patients with minor or without peripheral vascular disease (P<0.05 or p<0. 01).4. Controlling the influence of TG, TC, UAE, Scr, CCr, HDL-C and durationof diabetes, we still found that the severity of peripheral vascular disease in T2DM was negatively correlated with SDNN(r=-0. 556, p<0. 001), SDANN(r= -0. 539, p<0. 001), RMSSD(r=-0. 196, p=0. 02), SDNNind(r=-0. 361, p<0. 001) and PNN50(r=-0. 305, p<0. 001). CONCLUSIONS1. There is an impaired HRV in type 2 diabetic patients.2. The reduced HRV in T2DM patients is associated with the complicated peripheral vascular disease and is negatively correlated with the severity of peripheral vascular disease.3. HRV is an independent correlative factor for type 2 diabetic peripheral vascular disease and it may be a risk factor for type 2 diabetic peripheral vascular disease.