Effects of Empagliflozin in Different Phases of Diabetes Mellitus-related Cardiomyopathy

Background: In diabetes mellitus-related cardiomyopathy (DMCMP), hyperglycemia causes endothelial dysfunction, fibrosis, and myocardial injury, which result in left ventricular (LV) dysfunction. Treatment with sodium–glucose co-transporter 2 inhibitor (SGLT2i) reduces the risk of exacerbation of heart failure (HF). The beneficial effects of SGLT2i on HF depend not only on indirect actions such as osmotic diuresis but also direct actions on the myocardium leading to improvements in LV function. However, it remains unclear whether SGLT2i treatment is equally effective in any phase of DMCMP. The aim of this observational study was to compare the efficacy of SGLT2i treatment on LV dysfunction between early and advanced DMCMP. Methods: Thirty-five symptomatic non-ischemic HF patients with LV ejection fraction (EF) greater than 40% and type 2 diabetes mellitus (T2DM) treated with administration of empagliflozin (10 mg/day) were enrolled. According to the myocardial extracellular volume fraction (ECV), a reliable marker of cardiac fibrosis quantified by cardiac magnetic resonance, the patients were divided into the early DMCMP group (n = 16, ECV ≤ 30%) and advanced DMCMP group (n = 19, ECV > 30%) and followed-up prospectively. Echocardiography was performed at baseline and after 12 months. LV systolic function assessed as LV global longitudinal strain (GLS) and diastolic function assessed as the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity (E/e’) were compared. Results: ECV was strongly correlated with T2DM duration (r 2 = 0.65, p < 0.001). At baseline, both groups had similar backgrounds (LVGLS: 7.9 ± 2.4% vs. 6.7 ± 3.0%, p = 0.207, and E/e’: 13.2 ± 6.1 cm/s vs. 12.6 ± 3.8 cm/s, p = 0.694). After 12 months, the early DMCMP group showed greater improvement in LVGLS (ΔLVGLS: 4.6 ± 1.5% vs. 1.6 ± 3.3%, p = 0.003) and E/e’ (ΔE/e’: -3.4 ± 5.5 cm/s vs. -0.1 ± 3.5 cm/s, p = 0.043) than in the advanced DMCMP group. Conclusion: The positive effects of empagliflozin on LV dysfunction were more remarkable in DMCMP with mild cardiac fibrosis than with advanced fibrosis. Early intervention of SGLT2i for DMCMP is preferable.