Overview of Medical Indication Type 2 diabetes mellitus is associated with increased heart failure risk. The increased risk results in part from poor glycemic control and obesity, but concomitant arterial hypertension may also contribute. In the Framingham Heart Study, heart failure risk increased by 5% in men and by 7% in women with each 1 kg/m2 increment in body mass index (BMI). Compared with normal weight subjects, obese subjects had a doubling of heart failure risk. Given the rapid increase in the prevalence of obesity and type 2 diabetes mellitus, the number of heart failure patients is likely to increase sharply.
Evidence Heart failure in obesity is explained by increased left ventricular mass and impaired left ventricular diastolic filling rather than systolic dysfunction. Obesity is associated with volume expansion and increased cardiac output. Arterial blood pressure also increases with increasing obesity. In addition, type 2 diabetes mellitus may directly elicit abnormalities in myocardial metabolism and function through intramyocardial triglyceride deposition and lipotoxicity. In a study from our group, obese women with insulin resistance showed increased myocardial lipid accumulation compared with obese insulin-sensitive women, and intramyocardial lipids were reduced by dietary weight loss. Finally, intramyocardial lipids are associated with impaired diastolic function in patients with type 2 diabetes mellitus. Myocardial insulin resistance may also contribute to heart failure, because genetic deletion of cardiac insulin receptors in mice worsens catecholamine-mediated myocardial injury. Heart failure risk may be further exacerbated through obesity-induced neurohumoral activation and systemic inflammation. Inflammatory cytokines are elevated in heart failure and modulate cardiac remodelling through various mechanisms including myocardial hypertrophy, fibrosis, and apoptosis.
Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new drug class for the treatment of type 2 diabetes mellitus. SGLT2 inhibitors may be particularly suitable in improving cardiac structure and function because they substantially improve systemic glucose metabolism, lower blood pressure, and reduce body weight. These effects reduce sympathetic vasomotor tone, and renin-angiotensin-system activity. Thus, SGLT2 inhibitors including empagliflozin ameliorate metabolic and hemodynamic risk factors tightly linked with left ventricular hypertrophy and heart failure risk. Recently published outcome data suggest a beneficial effect of empagliflozin on heart failure hospitalisation rates and on overall cardiovascular mortality in patients with type 2 diabetes and previously diagnosed cardiovascular disease.
Study Rationale Patients with type 2 diabetes mellitus are exposed to an excessive heart failure risk secondary to left ventricular hypertrophy and impaired diastolic filling, a condition not addressed by currently available treatments. The abnormality results from obesity-induced volume overload, increased blood pressure, and myocardial fat accumulation. By improving metabolism, body weight, and blood pressure, empagliflozin addresses the root causes of myocardial disease associated with type 2 diabetes-. We will assess left ventricular mass, function, and lipid content in patients with type 2 diabetes mellitus before and after 24 weeks treatment with metformin plus empagliflozin or glimepiride. We expect to observe improvements in left ventricular mass, function, and fat content with empagliflozin. The results of the study will help to understand the mechanisms of cardioprotective effects of empagliflozin that have been revealed recently.
