Author + information
- Tetsuro Tsujimoto, MD, PhD∗ ()
- ↵∗Department of Diabetes, Endocrinology, and Metabolism, Center Hospital, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
We appreciate the comments from Drs. Rodriguez-Granillo and Carrascosa on our recent study (1). The obesity paradox is observed in patients with heart failure. Possible explanations for this paradox include residual confounding, unintentional weight loss, unmeasured comorbidities, or selection bias (2). Puig et al. (3) recently reported that higher body mass index (BMI) and waist circumference were associated with a decreased risk of all-cause mortality in patients with heart failure. Although our study also observed an inverse relationship between BMI and mortality, several analyses showed that abdominal obesity was significantly associated with an increased risk of all-cause mortality in patients with heart failure with preserved ejection fraction (HFpEF) (1). The difference in results between the 2 studies may partially reflect the methods of the multivariable analysis. The former study used a backward stepwise method, and adjustment was made using selected variables. Additionally, the former study included patients with low BMI levels, which can include patients with undernutrition and unknown or unmeasured serious comorbidities. A sensitivity analysis excluding patients with a BMI of <18.5 kg/m2 may be needed to confirm the results. Moreover, the former study used waist circumference and not abdominal obesity. The definition of abdominal obesity differed for men and women, and that difference could influence the results. Furthermore, the 2 studies primarily differed in their study subjects: the former study included many patients with heart failure with reduced ejection fraction (HFrEF), whereas our study included only patients with HFpEF. The pathophysiology and characteristics of patients with HFpEF and HFrEF differ significantly. In addition, unlike HFrEF, little evidence supports any specific treatment for HFpEF. Our study results (1) suggest that abdominal obesity, not BMI, may be an important risk factor for mortality in patients with HFpEF. There were no significant interactions between abdominal obesity and clinically important subgroups including sex. The inability of BMI to accurately characterize the severity of obesity may be partially associated with the obesity paradox. BMI does not distinguish between fat and lean mass, and parameters such as waist circumference and waist-to-hip ratio measure body composition more accurately than BMI. Furthermore, not peripheral fat but central fat may be a more important risk factor for mortality in patients with HFpEF because visceral fat is more strongly associated with systemic inflammation. Our findings may support the recently proposed hypothesis that the presence of a systemic proinflammatory state is associated with the pathophysiological mechanisms underlying HFpEF. Further studies are needed to assess the effects of visceral fat and fat distribution on the development of HFpEF and mortality in these patients.
Please note: Dr. Tsujimoto has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
- Tsujimoto T.,
- Kajio H.
- Tsujimoto T.,
- Kajio H.,
- Sugiyama T.
- Puig T.,
- Ferrero-Gregori A.,
- Roig E.,
- et al.