Associations among obesity degree, glycemic status, and risk of heart failure in 9,720,220 Korean adults

Background: Recent studies suggest an association between diabetes and increased risk of heart failure (HF). However, the associations among obesity status, glycemic status, and risk of HF are not known. In this study, we analyzed whether the risk of HF increases in participants according to baseline glycemic status and whether this increased risk is associated with obesity status. Methods: We analyzed the risk of HF according to baseline glycemic status (normoglycemia, impaired fasting glucose [IFG], and diabetes) in 9,720,220 Koreans who underwent Korean National Health Screening in 2009 without HF at baseline with a median follow-up period of 6.3 years. The participants were divided into five and six groups according to baseline body mass index (BMI) and waist circumference, respectively. Results: Participants with IFG and those with diabetes showed a 1.08- and 1.86-fold increased risk of HF, respectively, compared to normoglycemic participants. Compared to the normal weight group (BMI, 18.5 to 22.9 kg/m²), the underweight group (BMI <18.5 kg/m²) showed a 1.7-fold increased risk of HF, and those with BMI ≥30 kg/m² showed a 1.1-fold increased risk of HF, suggesting a J-shaped association with BMI. When similar analyses were performed for different glycemic statuses, the J-shaped association between BMI and HF risk was consistently observed in both groups with and without diabetes. Conclusion: Participants with IFG and diabetes showed a significantly increased HF risk compared to normoglycemic participants. This increased risk of HF was mostly prominent in underweight and class II obese participants than in participants with normal weight.