Abstract
BACKGROUND: Obesity or underweight can complicate and aggravate symptoms and progression of right heart failure in patients with pulmonary arterial hypertension (PAH). This study investigates the influence of different body mass index (BMI) categories on right heart function and outcome in PAH patients. METHODS: In this cross-sectional study with survival follow-up (mean follow-up 3.1 ± 2.6 years, median 2.7 years), clinical measures such as WHO-functional class and invasively measured hemodynamic parameters at initial diagnosis of PAH were compared between different BMI groups. RESULTS: Out of 2055 data sets, 755 patients with PAH (62.5% female) were eligible for the study (65 ± 15 years, 44.9% idiopathic PAH, 64.8% WHO functional class III or IV). Out of them 15 patients (1.99%) were underweight (BMI < 18 kg/m(2)), 248 (32.85%) patients had a normal weight (BMI 18.5-25 kg/m(2)), 256 (33.91%) were overweight (BMI > 25 to 30 kg/m(2)) and 236 patients (31.26%) were classified as obese (BMI > 30 kg/m(2)). Worst survival was denoted for patients with BMI < 18.5 kg/m(2), best survival for BMI > 25 to 30 kg/m(2). Cardiac output (CO) significantly differed between BMI groups (p < 0.0001, R = 0.268) and sex. In multivariable age-adjusted survival analysis, BMI-status, sex and right ventricular function were identified as independent predictors of survival. CONCLUSIONS: This is the first study to assess RV function with regard to BMI status and survival in PAH. The study underlines the importance of the parameter body weight in the clinical management of PAH patients. It provides important insights in the relations of BMI and CO and documented significant gender differences.