Impact of hypoglycemia at the time of hospitalization for heart failure from emergency department on major adverse cardiovascular events in patients with and without type 2 diabetes

Background: Few studies have examined the association between hypoglycemic episodes among people with type 2 diabetes (T2DM) at the time of hospitalization for heart failure (HF) and cardiovascular outcomes. Methods: From March 2016 to June 2018, we conducted a retrospective cohort study to investigate hypoglycemia during HF hospitalization in the emergency department, three-point major adverse cardiovascular events (3P-MACE), and all-cause mortality; these were followed up through June 2021. HF hospitalization was defined according to American Heart Association criteria. Hypoglycemia was defined as a glucose level < 3.9 mmol/L at the time of HF hospitalization. We classified the enrolled patients into three groups (reference group, those without T2DM or hypoglycemia; those diagnosed with T2DM without hypoglycemia; and those with hypoglycemia and T2DM). We used Cox proportional hazard regression analysis to investigate the association between the three groups and the development of the first occurrence of 3P-MACE and all-cause mortality. Results: During a median of 25 months of follow-up, a total of 783 patients admitted due to HF were analyzed. In total, 159 (20.3%) cases of 3P-MACE were identified, and the mortality rate was 20.2% (n = 158). The median age of patients was 76.0 (65.0–82.0) years, and 49.0% were men. Patients with 3P-MACE had a lower body mass index (22.6 [20.4–25.1] vs. 23.8 [21.3–26.7]), higher frequency of previous history of HF (24.5% vs. 15.7%), T2DM (64.2% vs. 47.3%), higher rates of hypoglycemia at the time of HF hospitalization (19.5% vs. 7.7%), and lower eGFR levels (61.1 [36.0–80.7] mL/min/1.73 m² vs. 69.2 [45.8–89.5] mL/min/1.73 m²) than those without 3P-MACE. The multivariable adjusted HR of 3P-MACE was as follows: group with hypoglycemia and T2DM: HR, 2.29; 95% CI: 1.04–5.06; group with T2DM without hypoglycemia: HR: 1.42; 95% CI: 0.86–2.33; and all-cause mortality group with hypoglycemia and T2DM: HR: 2.58; 95% CI: 1.26–5.31, group with T2DM without hypoglycemia: HR: 1.32; 95% CI: 0.81–2.16; compared to the reference group (group without T2DM or hypoglycemia). Conclusions: T2DM and hypoglycemia are independent risk factors for 3P-MACE and all-cause mortality compared to those without hypoglycemia during HF hospitalization.