In 1972, Rubler et al1 reported the clinical and postmortem findings of a small cohort study involving 27 patients with diabetes. The vast majority of these patients (85%) had several other cardiovascular risk factors or evidence of ischaemic heart disease or valvular disease. After excluding these patients, the investigators found evidence of cardiomyopathy and heart failure in the remaining four patients with no apparent alternative cause other than diabetes. Intrigued by this somewhat puzzling finding, the authors coined the term ‘diabetic cardiomyopathy’, implying that diabetes causes heart failure independent of other established cardiovascular risk factors.

Since that early report, several much larger studies have investigated the association between diabetes and risk of heart failure and other cardiovascular conditions. For instance, in a recent study of 35 000 UK adults with prevalent type 2 diabetes without any known pre-existing cardiovascular disease, the risk of incident heart failure was 56% (CI 45% to 69%) higher than in those without diabetes.2 Estimates took account of conventional vascular risk factors, suggesting that diabetes increases the risk of heart failure independent of such factors.2 The strength of this association was similar to that for incident myocardial infarction (HR 1.54). Moreover, heart failure was found to be a more common initial manifestation of cardiovascular disease than myocardial infarction and angina,2 stressing the importance of this condition in patients with diabetes.

However, diabetes is not a single homogeneous disease. Among people with diabetes, the risk of heart failure (and other vascular outcomes) differs substantially. Skrtic et al3 investigate the association between glycaemic control and risk of incident heart failure in one of the largest contemporary cohorts of patients with type 2 diabetes. By making …