Epidemiologic and clinical data from the last 2 decades have led to the recognition that, in addition to myocardial infarction and other atherosclerosis-related cardiovascular events, heart failure is a major contributor to cardiovascular morbidity and mortality in patients with diabetes. In certain patients with diabetes, the observation that myocardial dysfunction is present in the absence of coronary artery disease, valvular disease, and the sequelae of associated cardiovascular risk factors1 has led to the use of the poorly understood term “diabetic cardiomyopathy.” This term was first used in 1972 by Rubler et al,2 describing myocardial dysfunction in patients with diabetes in the absence of coronary artery disease, hypertrophy, or valvular heart disease. There is ongoing discussion whether diabetic cardiomyopathy exists as a specific entity or not, as considered by Ernande and Derumeaux in their review from 2012, “Diabetic cardiomyopathy: myth or reality?” ۳ This ongoing discussion reflects the fact that little is known about the pathophysiology and the underlying molecular mechanisms of heart failure in patients with diabetes. Only recently have clinical and epidemiologic data demonstrated the incidence, prevalence, and prognosis of heart failure in patients with diabetes. To date, heart failure has been described as heart failure with preserved ejection fraction (HFpEF) or heart failure with reduced ejection fraction (HFrEF), according to left ventricular function. To dichotomize heart failure into these 2 entities has certain limitations and probably does not cover an intermediate stage that the most recent guidelines of the European Society of Cardiology (ESC) termed heart failure with a mid-range ejection fraction (HFmrEF; ejection fraction 40%-49%).4 This extended definition is a first step to better phenotyping and an improved taxonomy of heart failure. Nevertheless, clinical and epidemiologic data, as well as experimental data, have only focused on HFrEF and HFpEF. Therefore, we have used these 2 entities as the basis for the overview provided in this article.

Incidence and Prevalence of Heart Failure in Diabetes

Various epidemiologic data have shown that prediabetes is associated with a high risk of heart failure and suggest an age-adjusted hazard ratio (HR) between 1.2 and 1.7 in different populations of patients with impaired fasting glucose,5,6 although not confirmed in all studies.7 A large community-based cohort study of 6814 subjects without coronary vascular disease at baseline was followed for 4 years, and the incidence of heart failure, depending on the presence of metabolic syndrome, was analyzed.8 This study showed that features of metabolic syndrome are associated with an increased risk of heart failure, with two-thirds of patients developing HFrEF. The risk of developing heart failure in subjects with “prediabetes” is lower than in subjects with manifest diabetes