Both high and low body mass indexes are prognostic risks in Japanese patients with chronic heart failure: implications from the CHART study

Background: Prognostic impact of body mass index (BMI) in Japanese patients with chronic heart failure (HF) remains unclear.

Methods and results: We examined the relationship between BMI and the prognosis of Japanese HF patients in the Chronic Heart Failure Analysis and Registry in the Tohoku District (CHART) study. The study sample was 972 Japanese chronic HF patients (mean age, 68.2 ± 13.5; male 65.2%). We categorized them into 5 groups; BMI <18.5, 18.5 to 22.9, 23.0 to 24.9 (reference), 25.0 to 29.9, and ≥ 30.0. Using a Cox hazards model, the relationships between BMI and deaths or admission for worsening HF were studied in detail. Mean follow-up period was 3.4 ± 1.7 years. Multivariate analysis showed that, as compared with reference group (BMI 23.0 to 24.9), hazard ratios (HR) for all-cause death showed a U-shaped association with 1.70 (95% confidence interval; 1.04-2.76), 1.23 (0.85-1.78), 1.26 (0.84-1.90), and 2.75 (1.51-5.00) among those with BMI<18.5, 18.5 to 22.9, 25.0 to 29.9, and ≥ 30.0, respectively. There were significant and suggestive U-shaped associations between BMI and cardiac-cause death or admission for worsening HF.

Conclusions: Both high and low BMIs were associated with increased outcomes, suggesting that extreme obesity is not beneficial in improving the prognosis of Japanese chronic HF patients.