The Impact of Body Mass Index on Survival and Clinical Outcomes in Pulmonary Arterial Hypertension: Revisiting the Obesity Paradox.

OBJECTIVE: This study aims to investigate the impact of body mass index (BMI) on survival outcomes and clinical characteristics in patients with pulmonary arterial hypertension (PAH). Given the conflicting evidence on the "obesity paradox," we sought to further explore this phenomenon within a demographically diverse cohort at Louisiana State University Health Sciences Center in Shreveport. MATERIALS AND METHODS: We conducted a retrospective observational study of PAH patients aged 18 years and older who received care at our institution from 2019 to 2022. Patients were categorized by BMI as normal (<25 kg/m²), overweight (25-30 kg/m²), and obese (>30 kg/m²). Clinical and demographic data, including age, gender, comorbidities, PAH subtype, and functional measures, were collected. Hemodynamic parameters, right heart catheterization (RHC) findings, and functional assessments were also included. Survival analysis was conducted using the Kaplan-Meier method, with group comparisons performed via ANOVA and chi-squared tests. RESULTS: A total of 69 patients were included, with 55.1% classified as obese, 26.1% as overweight, and 18.8% as having a normal BMI. The majority of patients were female (72%) and African American (44.8%). Although obese patients displayed more severe hemodynamic measures, including higher mean pulmonary artery pressure (mPAP) and greater right ventricular dysfunction, the survival analysis showed that the obese group had a non-significant trend toward better survival outcomes compared to normal BMI and overweight groups. Functional improvements on the 6-minute walk test (6MWT) post-treatment were also more pronounced in the obese group. CONCLUSION: Our findings contribute to the understanding of the obesity paradox in PAH, revealing a potential trend toward improved survival in obese PAH patients despite more adverse hemodynamic profiles. These results underscore the need for further research to elucidate the mechanisms underlying the obesity paradox in PAH and to determine if BMI-targeted management strategies may benefit this population.