Hardening and thickening of the walls of the arteries as a result of deposits of atheroma (fatty material) on their inner lining. This build-up of atheroma may slow down or stop blood flow.
It indicates abnormalities of the lipid metabolism and is often associated with insulin resistance in type 2 diabetes.
'Mini strokes' that produce stroke-like symptoms and signs which clear completely within 24 hours. These attacks are strong predictors of stroke.
"The link between diabetes and CVD is so strong that the prevention agenda for both diseases can be linked and integrated at many levels of the system. The high CVD risk in people with IGT and newly-diagnosed diabetes also emphasizes both the importance of primary prevention of diabetes in the context of overall prevention of CVD and the significance of diabetes as an 'entry point' for overall, comprehensive cardiovascular risk management."
Cardiovascular disease (CVD) is the major complication of type 2 diabetes and is responsible for more than 50% and up to 80% of deaths in people with diabetes as well as for very substantial morbidity and loss of quality of life.
Diabetes can lead to cardiovascular damage in a number of ways. The processes do not develop independently, and each may accelerate or worsen the others. Thus, as diabetes progresses, the heart and blood vessels are exposed to multiple attacks.
Cardiovascular death rates are either high or appear to be climbing in countries where diabetes is prevalent. The outlook for cardiovascular disease is alarming when one considers the number of people with diabetes worldwide and that this is set to more than double by 2025. The recent decline in cardiovascular disease in the USA, Australasia and western Europe may be compromised significantly by this upsurge in diabetes. In other parts of the world where CVD has been proliferating in recent years, the additional impact of diabetes threatens to have devastating consequences.
However, many cardiovascular deaths are potentially preventable in both people with and without diabetes if action is taken to systematically address the known risk factors. While some risk factors are fixed, such as age, gender and genetic background, many others are modifiable, such as high blood pressure, lipid abnormalities, obesity and smoking. More information on diabetes and cardiovascular disease can be found at www.cvd.idf.org.
Major cardiovascular complications
Global mortality data for cardiovascular disease
Prevalence of cardiovascular disease in people with diabetes
The most important cardiovascular complications of diabetes are:
Given the global epidemic of diabetes, the double threat of diabetes and CVD is set to explode unless preventative action is taken. It is noteworthy for example that, in some Western populations, CHD rates have declined in the overall population but no consistent decline is seen in people with diabetes1Gu K, Cowie CC, Harris MI. Diabetes and decline in heart disease mortality in US adults. J Am Med Assoc 1999; 281:1291-1297..
The impact of cardiovascular disease in diabetes is exacerbated even further by the earlier age of onset of type 2 diabetes which is now reaching down even to children and adolescents, and carries the threat of early onset of CVD. In addition, advances in insulin therapy have improved the life expectancy of people with type 1 diabetes and each year of prolonged life increases the likelihood of cardiovascular complications.
Diabetes belongs to a special risk category as it has so marked an effect on cardiovascular risk. As well as being a risk factor in its own right, diabetes is associated with a higher prevalence of other common risk factors such as hypertension and dyslipidaemia, and, these risk factors, in turn, have a more harmful effect in the presence of diabetes. For each risk factor present, the risk of cardiovascular death is about three times greater in people with diabetes compared to those without diabetes.
The end result is that people with diabetes are two to four times more likely to develop CVD than the general population (see figure below). In the case of CVD, silent myocardial infarction is common and the risks of sudden death and heart failure are also increased. In the case of stroke, transient ischaemic attacks are two to six times more common in the diabetic population and vascular dementia is also more common. In the case of PVD, people with diabetes have a 15-40 times increase in the risk of lower limb amputation compared to the general population.
These statistics also conceal additional problems. For a given major vascular event such as myocardial infarction or stroke, the outcome is worse in people with diabetes compared to the general population (see figure below). This results from both the severity and widespread nature of atherosclerosis in diabetes, combined with other causes of vascular disease in diabetes such as arterial stiffness, microangiopathy and autonomic neuropathy.
It is important to note also that even at the stage of impaired glucose tolerance (IGT), before full-blown diabetes has developed, the risk of cardiovascular disease is already increased by about two times compared to people with normal glucose tolerance.
An effective prevention strategy for CVD should include each of the following components:
The maps show the global burden of cardiovascular disease by using mortality data for coronary heart disease and cerebrovascular disease from individual countries. The use of mortality data, obtained principally from the Global Cardiovascular Infobase, serve to indicate the magnitude of the problem and to highlight regional differences and trends. It should be noted that considerable differences exist in the degree of completeness of the vital registration data submitted by countries. In some countries, the vital registration data system covers only a part of the country (for example urban areas, or some provinces only). In some other countries, although the vital registration data system covers the whole country, not all deaths are registered. Further details on data sources and methodology can be found in the Diabetes Atlas, second edition.
It should be emphasized also that these data provide the overall picture of total CVD mortality and are not limited to CVD in the context of diabetes.