Extracellular volume fraction and native T1 mapping in diabetic cardiomyopathy: a comprehensive meta-analysis.

Background: Type 2 diabetes mellitus (T2DM) is associated with myocardial fibrosis (MF), a major contributor to adverse cardiovascular outcomes. Cardiovascular magnetic resonance (CMR), specifically extracellular volume fraction (ECV) and native T1 mapping, offers a non-invasive approach to quantify MF. This study aims to evaluate the utility of ECV and native T1 mapping as biomarkers for cardiac fibrosis and to assess their relationship with diabetes severity, measured by hemoglobin A1C (HbA1C), in patients with T2DM.

Methods: A systematic review and meta-analysis were conducted following PRISMA guidelines. Comprehensive searches identified 19 eligible studies comprising 4,117 participants. Weighted mean differences (WMDs) were calculated for ECV and native T1 values between diabetic and non-diabetic groups. Meta-regression assessed the correlation between ECV and HbA1C. Sensitivity and subgroup analyses were performed to explore heterogeneity.

Results: Diabetic patients exhibited significantly higher ECV values than controls (WMD: 2.17; 95% CI: 1.32-3.02), consistent across subgroups excluding cardiac comorbidities (WMD: 2.02; 95% CI: 0.74-3.31). HbA1C levels were also significantly elevated in diabetics (WMD: 1.78; 95% CI: 1.37-2.19). However, no significant difference in native T1 values was observed (WMD: 13.40; 95% CI: -13.98-40.79). Meta-regression revealed no significant correlation between ECV and HbA1C, potentially due to limited data and high heterogeneity (I²: 93.37%).

Conclusions: ECV is a promising marker for quantifying MF in T2DM, demonstrating significant differences between diabetics and controls. The lack of correlation between ECV and HbA1C underscores the complexity of MF in diabetes and highlights the need for further research. Future studies with standardized protocols are essential to validate these findings and refine the use of CMR in diabetic cardiomyopathy.