Introduction on Diabetes Management – Lowering Cardiovascular Risk
The increasing worldwide prevalence of diabetes mellitus (DM) means almost 360 million people are suffering from this disease (in 2011) and it is estimated to reach 552 million people by 2030.1 The latest European Action on Secondary Prevention by Intervention to Reduce Events (EuroASPIRE) study (2013) has revealed that the mean prevalence of DM in European patients with coronary artery disease (CAD) is around 38 %, with Cyprus leading the way with 55 % and Russia coming last with 27 %.2 Morbidity and mortality from cardiovascular disease is 2–5 times higher in patients with DM compared with the general population, and diabetes provides a two-fold increase of risk of other vascular diseases independent of other risk factors.3
Multiple studies have shown that hyperglycaemia is associated with an increased risk for coronary heart disease as well as atherosclerotic disease. This is true both for diabetic patients and those with impaired glucose tolerance, although the risk varies between 2–4 times in diabetic patients and 1.5 times for patients with impaired glucose tolerance. Whether impaired fasting glucose also carries additional risk is controversial. Glycaemic control therefore appears to be of utter importance especially since just half of the European patients with CAD screened by EuroASPIRE IV attained a <7.0 % glycated haemoglobin (HbA1c) and only 35 % of them scored <6.5 %.2 Based on the results of several studies, a HbA1c reduction of ~1 % is associated with 15 % relative risk reduction in non-fatal myocardial infarction but without benefits on stroke or all-cause mortality.4 A HbA1c <7.0 % target was shown to reduce microvascular disease but has yet to prove a major benefit on macrovascular risk. Tight glycaemic control exerts a favourable effect on cardiovascular diseases, which is visible only after many years. However, a combination of glucose control with lipid-lowering medication and antihypertensive medication leads to an improvement in the rate of cardiovascular events.1 Moreover, although the remaining normoglycaemic population appears to be larger than previously recorded by the EuroASPIRE III trial (33.7 versus 29.5 %), the prevalence of DM has increased from 23.5 % to 26.8 %, not counting the newly diagnosed cases (13.4 %). This was probably owing to the decrease in the population with impaired fasting glucose and impaired glucose tolerance who have likely developed DM between the two EuroASPIRE trials.2 Yet, as crucial as glycaemic control is, just half of the European population is aware of their glucose levels, ranging from 96 % in Slovenia to 8 % in Belgium.2 This attitude should be changed since successful glucoselowering therapy is most efficient when supported by self-monitoring of blood glucose.
A statistic concerning the mortality rate among the diabetic population places cardiovascular disease in the top leading causes of death. Therefore, ischaemic heart disease is by far the most important cause of death for patients with type 2 DM followed by other heart diseases and stroke, while diabetes itself comes in fourth.12