Diabetes and Vascular Disease
In a community based study in China, the overall prevalence of Peripheral Vascular Disease (PVD) was 12.2% in the hyperglycemic population. The prevalence of PVD in the diabetics was 15.1%, significantly higher than that of the IGR( Impaired glucose regulation) subjects (7.7%). The rate of intermittent claudication in those with the ABI </= 0.9 was 13.5%.
Multiple randomized control trials as well as meta-analyses have shown a clear relationship between improvement in microvascular complications, namely nephropathy, retinopathy and neuropathy in both Type 1 and 2 diabetes. There has not been however, that robust of a correlation in improvement in macrovascular complications and intensive diabetes control in various randomized control studies.
Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study established the importance of tight glycemic control for protection against microvascular and cardiovascular disease (CVD) in type 1 diabetes.
In the United Kingdom Prospective Diabetes Study (UKPDS), although the role of glycemic control on microvascular disease in type 2 diabetes was clearly documented, its role in reducing cardiovascular risk was not established as clearly for type 2 diabetes.
In addition to atherogenic effects from the diabetes-related dyslipidemia (elevated triglycerides, low level of HDL cholesterol, and small/dense LDL particles), many clinical and experimental studies reveal that high levels of insulin precede development of arterial diseases.
Clinically, the overall risk increase conferred by type 2 diabetes is driven by accelerated progression of pre-existing atherosclerosis to clinical cardiovascular events.
Hyperglycemia, sensory and autonomic neuropathy, and peripheral arterial disease all contribute to the pathogenesis of lower extremity infections in diabetic patients. These infections are associated with substantial morbidity and mortality.
Compared with individuals without diabetes mellitus, those with diabetes have a higher prevalence of coronary heart disease (CHD), a greater extent of coronary ischemia, and are more likely to have a myocardial infarction (MI) and silent myocardial ischemia. The National Cholesterol Education Program report from the United States and guidelines from Europe consider type 2 diabetes to be a CHD equivalent, thereby elevating it to the highest risk category.
Patients with diabetes have a greater burden of atherogenic risk factors than nondiabetics, including hypertension, obesity, and lipid abnormalities.
A variety of mechanisms may contribute to the increase in CHD risk in patients with diabetes, including endothelial dysfunction, platelet activation, coagulation abnormalities, and atherosclerotic plaque composition.
Risk factor reduction is effective for the secondary prevention of cardiovascular disease. This is particularly relevant to patients with diabetes since diabetes is considered to be a CHD equivalent.
The ACCF/AHA guidelines for management of Peripheral Arterial Disease give the following recommendations for Diabetic patients with PAD:
1. Proper foot care, including use of appropriate footwear, chiropody/
podiatric medicine, daily foot inspection, skin cleansing, and use
of topical moisturizing creams, should be encouraged and skin
lesions and ulcerations should be addressed urgently in all
patients with diabetes and lower extremity PAD. (Level of
1. Treatment of diabetes in individuals with lower extremity PAD by
administration of glucose control therapies to reduce the hemoglobin
A1C to less than 7% can be effective to reduce microvascular
complications and potentially improve cardiovascular outcomes.
(Level of Evidence: C)
Multifactorial risk reduction — Vigorous cardiac risk reduction (smoking cessation, aspirin, blood pressure control, reduction in serum lipids, preferably using a statin, diet, exercise, and, in high-risk patients, an angiotensin-converting enzyme [ACE] inhibitor) should be a top priority for all patients with type 2 diabetes.
In spite of evidence that aggressive risk factor reduction lowers the risk of both micro- and macrovascular complications in patients with diabetes, the vast majority of patients do not achieve recommended goals for A1C, blood pressure control, and management of dyslipidemia.