Objective: To investigate the correlation between body mass index (BMI) and pulmonary artery systolic pressure in a large population of patients with pulmonary arterial hypertension (PAH).
Patients and methods: The BMI of patients with group 1 PAH enrolled in the Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL) was compared with that of age- and sex-matched controls in the National Health and Nutrition Examination Survey (NHANES) to clarify whether obesity is linked with PAH. The diagnosis of PAH was defined in REVEAL by right-sided heart catheterization. Differences in BMI and the percentage of patients considered obese (BMI ≥30) and underweight (BMI <18.5) in various subgroups of patients enrolled in REVEAL from March 30, 2006, through September 11, 2007, were determined.
Results: Mean BMI was no different for patients with PAH (n=2141) than for the NHANES normal comparison group; however, the proportion of obese and underweight patients was increased in patients with PAH. Subgroup analysis demonstrated that subgroups with idiopathic PAH and those with PAH associated with drugs and toxins had both higher BMI and percentage of obese patients, whereas 3 other subgroups (those with PAH associated with congenital heart disease, connective tissue disease, and human immunodeficiency virus) had lower mean BMI.
Conclusion: Mean BMI of the REVEAL patients was the same as that of the NHANES normal comparison group; however, there were higher percentages of obese and underweight patients in REVEAL. This discrepancy can be explained by the balancing effect of more overweight and underweight patients in different PAH subgroups. The reason for the increased frequency of obesity in idiopathic PAH is unknown, and additional study is needed.
Trial registration: ClinicalTrials.gov NCT00370214.