Waist-to-height ratio may have stronger prognostic value vs. BMI in HF
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Key takeaways:
- Waist-to-height ratio may be more prognostic of heart failure outcomes than BMI.
- The finding could question validity of the obesity paradox in patients with heart failure.
Alternative anthropometrics, such as waist-to-height ratio, may better predict HF hospitalization and CV death in patients with HF with reduced ejection fraction and overweight compared with BMI alone, researchers reported.
These findings may question the validity of the “obesity paradox” of reduced mortality among patients with HF who are overweight compared with normal weight, according to a study published in the European Heart Journal.
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“Although obesity has been repeatedly shown to be an independent risk factor for the development of HF, its prognostic importance in established HF, especially HFrEF, is less clear and an ‘obesity-survival paradox’ has been described in patients with HFrEF,” Jawad H. Butt, MD, research fellow in the department of cardiology at Rigshospitalet at Copenhagen University Hospital in Denmark, and colleagues wrote. “However, the associations between obesity and outcomes in HFrEF have generally been based on BMI ... which has many limitations as a measure of adiposity. BMI does not take into account the location of body fat or its amount, relative to muscle, or the weight of the skeleton, which may differ according to sex, age and race.”
To test the prognostic value of waist-to-height ratio compared with BMI in patients with HFrEF, Butt and colleagues used data from the randomized, double-blind, placebo-controlled PARADIGM-HF trial, which was designed to assess the efficacy and safety of sacubitril/valsartan (Entresto, Novartis) compared with ACE inhibition with enalapril, on top of standard care, in patients with HFrEF.
As Healio previously reported, in the PARADIGM-HF trial, sacubitril/valsartan reduced risk for death and HF hospitalization in patients with HFrEF compared with enalapril.
Prognostic values
The primary outcome of the present analysis was HF hospitalization or CV mortality.
Median BMI was 27.5 kg/m2 among men and 27.6 kg/m2 among women.
Median waist-to-height ratio was 0.58 among men and 0.59 among women.
Researchers initially observed an obesity paradox of lower mortality among participants with BMI of 25 kg/m2 or more compared with normal weight.
However, the association between BMI and CV death was attenuated after adjustment for prognostic variables, including N-terminal pro-B-type natriuretic peptide, and the association between elevated BMI and HF hospitalization was accentuated.
In a similarly adjusted analyses of waist-to-height ratio by quintile, the highest quintile of waist-to-height ratio was associated with increased risk for all-cause death (adjusted HR = 1.1; 95% CI, 0.87-1.39) and HF hospitalization (aHR = 1.39; 95% CI, 1.06-1.81) compared with the lowest quintile.
Moreover, analysis of both BMI and waist-to-height ratio indicated associations between adiposity risk for the primary outcome; however, the association was stronger for waist-to-height ratio and persisted after adjustment when comparing the highest quintile with the lowest (aHR for CV death = 1.15; 95% CI, 0.88-1.49; aHR for HF hospitalization = 1.39; 95% CI, 1.06-1.81).
“Among the patients with HFrEF in PARADIGM-HF, there was no longer evidence of a BMI-related ‘obesity-survival paradox’ after comprehensive adjustment for other prognostic variables,” the researchers wrote. “Moreover, the counterintuitive epidemiologic observation of a lower risk of death in patients with greater adiposity was less apparent with the newer anthropometric indices. All anthropometric indices examined showed that greater adiposity was associated with a higher risk of HF hospitalization as this was more evident with the newer indices.”
Results ‘raise the alarm’ around the obesity paradox
In a related editorial, Ryosuke Sato, MD, PhD, fellow, and Stephan von Haehling, MD, PhD, professor, both in the department of cardiology and pneumology at the University Medical Centre Göttingen in Germany, discussed how these findings may affect the debate surrounding the obesity paradox.
“The present study ... provides no new evidence for the existence of an obesity paradox in patients with HFrEF by either BMI or waist-to-height ratio anthropometric measurements,” the authors wrote. “It also showed that adiposity assessed by the waist-to-height ratio not only more definitely eliminates the paradox, but also is associated with a higher risk of HF hospitalization than BMI; however, the obesity paradox was never intended to predict hospitalizations.
“The present findings raise the alarm over the term ‘obesity paradox,’ which has been claimed to be based on BMI,” the wrote. “Can we tell obese HF patients just to stay as they are? To adequately address this question, not only should the obesity paradox be revisited even in patients with HF with preserved ejection fraction and in lean HF patients by [waist-to-height ratio], which better reflects pathophysiological processes of obesity, but also further tests are warranted to validate the effect of weight loss in ‘truly’ obese HF patients with a high [waist-to-height ratio].”
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