Diabetes-related differences in body composition and their prognostic value among patients with heart failure and preserved ejection fraction: a cardiac-MRI-based study

Background: Heart failure and diabetes mellitus share common risk factors and can independently regulate the body composition profile of patients. Approximately one-third of patients with heart failure and preserved ejection fraction (HFpEF) have concomitant diabetes mellitus, but the additional impact of diabetes on the body composition of HFpEF patients and its associations with prognosis have not been explored. Methods: This study included 281 HFpEF patients, among whom 87 had type 2 diabetes (T2DM). On the basis of their cardiac magnetic resonance (MR) images, regional adipose tissue (including subcutaneous, visceral and paracardial adipose tissue) as well as thoracic skeletal muscle were measured and compared between the diabetic and non-diabetic groups. Clinical endpoints were recorded and the predictive performance of body composition parameters and body mass index (BMI) for adverse events was assessed using multivariable Cox regression analysis in the overall HFpEF population and subgroups stratified by diabetes. Results: HFpEF patients with concomitant diabetes were significantly older (65.06 ± 12.92 vs. 57.98 ± 14.44 years, p < 0.001). The LVEDV index and LVSV index were significantly lower in the T2DM group. The paracardial adipose tissue (ParaAT index) was noticeably greater in the T2DM group than in the non-T2DM group (76.21 vs. 65.60 ml/m2, p = 0.005). In the overall HFpEF population, the increase in the skeletal muscle index (SMI) corresponded to a linear decrease of prognostic risks. In contrast, the increase in the ParaAT-VAT ratio and ParaAT-muscle ratio corresponded to linearly increasing risks of poor outcomes. BMI demonstrated a non-linear correlation with survival risks (p for nonlinearity: 0.031) and the lowest tertile compared with the middle tertile increased survival risks significantly. Subgroup analysis revealed that the prognostic risks associated with the ParaAT-VAT ratio and ParaAT-muscle ratio were greater in diabetic HFpEF patients (adjusted HR: 1.069 [1.022, 1.117] and 1.948 [1.391, 2.729], respectively) than in nondiabetic patients (adjusted HR: 1.053 [1.006-1.103] and 1.597 [1.018, 2.505], respectively). Protective role from increased SMI persisted among the non-T2DM patients (adjusted HR: 0.968 [0.951, 0.985], p < 0.001) but not among the T2DM patients (adjusted HR: 0.990 [0.968, 1.012], p = 0.380). The lowest tertile group of BMI for non-T2DM patients or instead, the highest tertile group of BMI for T2DM patients led to an unfavorable prognosis. Conclusions: Concomitant diabetes exacerbated paracardial adipose excess among HFpEF patients and worsened the association between body composition and adverse outcomes.