Elevated BMI linked to better survival in severe pulmonary hypertension

In a study presented at the American Thoracic Society International Conference, patients with severe pulmonary hypertension who were obese or morbidly obese had a significantly reduced risk for 1-year mortality compared with patients who had a BMI in the normal range.

Researchers evaluated data from 1,137 patients with severe pulmonary hypertension (pulmonary artery systolic pressure >60 mm Hg and ejection fraction >50%). Patients were stratified into three groups according to BMI: normal (18-24.9; n=361); obese (25-39.9; n=639) and morbidly obese (≥40; n=137). The mean age of the cohort was 71 years, and 69% were women.

Recent studies have suggested that obesity and a larger waist circumference may have a protective effect against congestive HF, and they referred to this observation as the “obesity paradox.”

“Obesity-related illnesses, particularly obesity hypoventilation syndrome and sleep apnea, may play a role in the development of pulmonary hypertension, and so we examined whether protective effects of obesity seen in patients with HF were also seen in these patients,” researcher Jose Caceres, MD, of Jacobi Medical Center/Albert Einstein College of Medicine in Bronx, N.Y., said in a press release.

At 1 year, the mortality rate was 34.1% in the normal BMI group, 22.8% in the obese group and 12.4% in the morbidly obese group (P<.001). Researchers determined a significant association between higher BMI and reduced mortality risk among obese (RR=0.616; 95% CI, 0.484-0.53) and morbidly obese patients (RR=0.306; 95% CI, 0.184-0.508) vs. the normal BMI group.

Rates of hospital readmission were 1.9% in the normal BMI group, 3.4% in the obese group and 3.1% in the morbidly obese group (P=.355).

“An obesity paradox may also occur in patients with significant pulmonary hypertension,” researcher Ronald Zolty, MD, also from Jacobi Medical Center/Albert Einstein College of Medicine, said in the release. “A possible mechanism underlying this phenomenon is increased levels of serum lipoproteins associated with increased body fat, which may play a role in neutralizing circulating toxins and inflammatory proteins.”

For more information:

Caceres JD. Abstract #54123. Presented at: the American Thoracic Society International Conference; May 16-21; San Diego.

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