Type 2 diabetes increases the risk of mortality and cardiovascular events in ischemic HFmrEF patients: a retrospective cohort study

BACKGROUND: Type 2 diabetes mellitus (T2DM) is known to worsen the prognosis of heart failure (HF), but its specific impact on patients with ischemic versus non-ischemic heart failure with mildly reduced ejection fraction (HFmrEF) remains unclear due to limited research and conflicting evidence. METHODS: We conducted a retrospective study of 1,691 HFmrEF patients at Xiangtan Central Hospital. Participants were divided into four groups: ischemic with T2DM (467 patients), ischemic without T2DM (856 patients), non-ischemic with T2DM (87 patients), and non-ischemic without T2DM (281 patients). We utilized the Cox proportional hazards model to analyze differences in all-cause mortality and cardiovascular events among the groups. RESULTS: After adjusting for multiple confounding factors using the Cox proportional hazards model, the ischemic heart disease and T2DM group had a significantly higher risk of all-cause mortality compared to the ischemic group without T2DM (HR = 1.5, 95% CI = 1.2-1.9, P = 0.001). The risk of cardiovascular events was also significantly increased (HR = 1.3, 95% CI = 1.1-1.5, P = 0.001). In non-ischemic HFmrEF patients, T2DM was not associated with a significantly increased risk of all-cause mortality (HR = 1.0, 95% CI = 0.6-1.7, P = 0.957) or cardiovascular events (HR = 1.3, 95% CI = 0.9-1.9, P = 0.113). CONCLUSION: T2DM significantly increases the risk of all-cause mortality and cardiovascular events in ischemic HFmrEF patients, while its impact on non-ischemic HFmrEF patients is limited. These findings underscore the importance of managing T2DM in patients with ischemic HFmrEF.