Preventing complications of diabetes

Aggressive management of hyperglycaemia and other risk factors can prevent many complications IN AUSTRALIA, 7% of the adult population has diabetes, 1 and the number of affected individuals is rising. Complications are the major cause of associated morbidity and mortality. They are classified as macrovascular (affecting large arteries) or microvascular (affecting capillaries and small blood vessels) (Box 1). The presence of complications almost triples the mean cost of managing diabetes per patient, from $4000 to $10 000 per annum. 2 The major aim of diabetes management is to prevent complications. Frequency of complications Among people with diabetes, about 15% have type 1 (formerly known as insulin-dependent diabetes), while about 85% have type 2 (formerly known as non-insulin-dependent diabetes). In type 1 diabetes, the major risk is microvascular complications , although macrovascular complications are also increased. The primary risk factor is hyperglycaemia, although other risk factors, such as hypertension and dyslip-idaemia, may occur secondary to uncontrolled hyperglycae-mia or renal disease (Box 2). Complications are therefore usually acquired after diagnosis. In contrast, type 2 diabetes is usually part of the " metabolic syndrome " , which is associated with other risk factors from early in the disease process, including abdominal obesity, hypertension, dyslipidaemia, a prothrombotic state and insulin resistance (Box 2). Although macrovascular disease is the major cause of morbidity and mortality in type 2 diabetes, 3 microvascular complications are often present when diabetes is diagnosed, even in people with no symptoms. Prevalences at diagnosis are: retinopathy, about 20%; neuropathy, 9%; and overt diabetic nephropathy, up to 10%. Type 2 diabetes increases the risk of coronary heart disease two-to fourfold and abolishes the protectiveness of female sex observed in the non-diabetic population. 4 The presence of diabetes also worsens the prognosis of coronary heart disease. Macrovascular complications Large-vessel disease, including coronary heart disease and stroke, is the greatest overall cause of morbidity and mortality in diabetes. Preventing these complications in type 2 diabetes, which is often associated with other cardiovascular risk factors, is a major challenge. Pathogenesis Hyperglycaemia promotes the reaction of glucose with components of the arterial wall to form advanced glycation products. These products cross-link with collagen, thereby increasing arterial stiffness. In dyslipidaemia, increased levels of low-density lipoprotein (LDL) cholesterol, consisting mostly of small dense particles, promote atherogenesis. Hypertension promotes the development and progression of vascular disease. Preventing macrovascular complications Finding strategies to reduce the development of macrovas-cular complications has …