Diabetic Cardiomyopathy

Type 2 Diabetes mellitus (T2DM) is a potent risk factor for the development of heart failure (HF). Even in the absence of traditional risk factors such as coronary artery disease, hypertension or significant valvular heart disease, T2DM can result in a state of abnormal myocardial structure and performance, termed diabetic cardiomyopathy.

The prevalence of diabetic cardiomyopathy is expected to increase in parallel with that of T2DM. In the US alone, an estimated 26 million adults are diagnosed with T2DM, 9.4 million adults have undiagnosed T2DM and 91.8 million adults have pre-diabetes (AHA 2021 update). Clinical trials show the prevalence of HF in patients with T2DM range from 19% to 26%. Conversely, T2DM is highly prevalent in those with HF, being reported in 25-40% of patients and associated with increased mortality.

Diabetic cardiomyopathy is associated with abnormalities of myocardial tissue structure affecting all cardiac chambers and all phases of cardiac function. Structural hallmarks include myocardial fibrosis and maladaptive changes in ventricular geometry including concentric left ventricular (LV) hypertrophy with potential LV dilatation in more advanced stages, with concomitant right ventricular (RV) involvement typified by early-onset eccentric RV hypertrophy, dilatation, and systolic impairment.

Functionally, diabetic cardiomyopathy is associated with abnormalities of LV diastolic performance, progressing from mild changes (delayed myocardial relaxation) to increased LV filling pressure frequently associated with left atrial enlargement and atrial fibrillation. This diastolic dysfunction often co-exists with systolic dysfunction ranging from highly prevalent reductions in LV longitudinal deformation with preserved ejection fraction (EF) which independently predict incident new-onset HF, to frank reductions in LV EF.

Patients with diabetic cardiomyopathy without symptomatic HF correspond to ACCF/AHA stage B HF, with the presence of structural and subclinical functional changes associated with increased risk of symptomatic HF and death. Clinically, LV dysfunction in diabetic cardiomyopathy can manifest with the full spectrum of HF phenotypes: HF with preserved EF (HFpEF), HF with mid-range EF (HFmEF), and HF with reduced EF (HFrEF).

References: Virani et al. Circulation. 2021;143:e254–e743; Widya et al. Diabetes Care. 2013 Feb; 36(2): 457–462; Kang et al. Am J Physiol Heart Circ Physiol. 2019 Jan 1;316(1):H113-H122; Wang et al. JACC Cardiovasc Imaging. 2018 Oct;11(10):1390-1400; Yancy et al. J Am Coll Cardiol. 2013 Oct 15;62(16):e147-239; Dunlay et al. Circulation. 2019 Aug 13;140(7):e294-e324.