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'Obesity paradox' identified in acute decompensated HF
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A lower BMI was associated with a higher risk for death, disease severity and age in a recent study.
“Obesity is associated with incident HF, but is paradoxically associated with better prognosis during chronic HF,” researchers wrote.
The study was conducted to define the relationship between BMI and death in patients with acute decompensated HF across four continents. Researchers evaluated data on 6,142 patients with acute decompensated HF on hospital admission collected from 12 prospective observational studies. The incidence of 30-day and 1-year mortality after discharge was compared between normal-weight (BMI 18.5 to 25; n=2,197), overweight (BMI 25 to 30; n=2,243) and obese patients (BMI ≥30; n=1,702).
After adjustment for clinical risk factors, patients with a higher BMI were at decreased risk for mortality (11% decrease at 30 days, 9% decrease at 1 year) compared with patients with a lower BMI (P<.05). Event-free survival at 30 days and 1 year was highest among obese patients; overweight patients also had improved survival when compared with normal-weight patients.
Further adjustment for B-type natriuretic peptide and ejection fraction did not eliminate the significance of the association between higher BMI and survival, nor did the exclusion of patients with grade 3 obesity or patients collected from the largest referral center used in the study, according to the study findings.
Analysis according to age, diabetes status and ejection fraction indicated the observed risk decrease was significant only in patients older than 75 years (HR=0.82; 95% CI, 0.72-0.95), those with an ejection fraction <50% (HR=0.85; 95% CI, 0.79-0.92), those without diabetes (HR=0.86; 95% CI, 0.79-0.93) and those with de novo HF (P=.004).
“The ‘obesity paradox’ is confined to older individuals, decreased cardiac function, less cardiometabolic illness and recent onset HF, suggesting that aging, HF severity/chronicity and metabolism may explain the obesity paradox,” the researchers wrote.
The researchers noted that BMI measurement at baseline was more effective for mortality risk reclassification at 1 year than typical clinical risk markers (continuous net reclassification index=0.119; P<.001), particularly among patients who died during follow-up (net reclassification index=0.19 for events compared with –0.07 for non-events).
Further, the association with higher BMI with lower mortality persisted in Asia, Western Europe, Central Europe and North America.
“While these observations certainly do not endorse weight gain to ‘protect’ patients with established HF, the general implication is that a lower BMI in acute decompensated HF identifies those individuals at particularly high risk,” the researchers wrote. “This phenomenon is evident in patients previously classified as ‘normal weight,’ thereby possibly resetting what is considered the lower normative bound for BMI in the acute decompensated HF setting.
“Ultimately, while a high BMI may not be the arbiter of prognostic benefit in those hospitalized with HF, a normal BMI — especially in the context of cardiac function and older age — particularly signals adverse long-term prognosis,” they concluded.
Disclosure: See the full study for a list of relevant financial disclosures.
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