ABSTRACT
BACKGROUND - An obesity paradox, wherein obese patients have lower mortality, has been described in cardiopulmonary diseases, including pulmonary arterial hypertension (PAH). Our objective was to determine whether obesity and body mass index (BMI) are associated with mortality in patients with PAH.
METHODS - We assessed incident patients with idiopathic, drug-induced, and heritable PAH from the French PAH Registry. Cox regression and Kaplan-Meier analysis were used to assess the association between BMI and obesity with all-cause mortality.
RESULTS - Of 1255 patients included, 30% were obese. A higher proportion of females (65.1% vs 53.4%, p<0.01), drug-induced PAH (28.9% vs 9.2%, p<0.01), systemic hypertension, diabetes, and hypothyroidism were present in the obese group. More obese patients were in New York Heart Association class III (66.4% vs. 57.1%), fewer were class IV (11.8% vs 16.9%) (p<0.01), and 6-minute walk distance was lower (276±121 vs 324±146, p<0.01). Right atrial pressure, pulmonary wedge pressure and cardiac index were higher while pulmonary vascular resistance was lower in obese patients. Neither BMI (HR 0.99, 95%CI 0.97-1.01, p=0.41) nor obesity (HR 1.0, 95%CI 0.99-1.01, p=0.46) were associated with mortality in multivariable analyses. There was a significant interaction between age and obesity such that mortality increased among morbidly obese patients under 65 years old (HR 3.01, 95%CI 1.56-5.79, p=0.001).
CONCLUSIONS - Obesity was not associated with mortality in the overall population, but there was an age-obesity interaction with increased mortality among young morbidly obese patients. These results have implications for active weight management in younger morbidly obese patients who are otherwise candidates for lung transplantation.
Copyright © 2018. Published by Elsevier Inc.