Statistics from Altmetric.com
More than 150 million subjects have diabetes mellitus (DM) worldwide and the number is expected to increase further.w1 Many cases, however, are undiagnosed and do not receive appropriate treatment. The risk of coronary artery disease (CAD) for patients with overt DM is increased by two to three times for men and three to five times for women compared to individuals without DM.1 CAD accounts for 75% of all deaths in DM patients while 30% of patients presenting with acute coronary syndromes have DM.w1 International guidelines consider DM as an equivalent of CAD requiring aggressive anti-atherosclerotic treatment. In the general population, the most typical clinical manifestation of myocardial ischaemia is the occurrence of chest pain. In DM patients, however, myocardial ischaemia is often expressed by angina equivalents: dyspnoea, arrhythmias and (pre-) syncope rather than typical angina. The outcome of CAD events may be three times worse in DM patients who have shortness of breath as a primary symptom. Diabetic patients have a high incidence of occult CAD, reflected by an increased incidence of silent myocardial infarction and ischaemia. The available evidence suggests that occult CAD is a common finding among asymptomatic DM patients, ranging from 20% in healthier subjects to >50% in patients with more complicated DM.w2 This poses the challenge of how to efficiently identify CAD in DM, for diagnosis, referral for invasive coronary angiography, and risk stratification. Various non-invasive methods are available and their diagnostic and prognostic value will be discussed.
Although a resting 12 lead ECG should be recorded in every DM patient to detect signs of CAD, one should realise that its diagnostic value is limited for several reasons. The ECG is normal in approximately 50% of patients with CAD and often abnormalities are not sufficiently specific for the diagnosis of CAD. Pathologic …