The Obesity Paradox Existing in Idiopathic Pulmonary Arterial Hypertension

Özet

Objectives: Our purpose was to evaluate the association between idiopathic pulmonary arterial hypertension (PAH) and obesity, as indicated by the body-mass index (BMI), in terms of the all-cause mortality in a group of patients from a specialized center. Materials and Methods: In this study, we retrospectively analyzed 78 consecutive adult patients with idiopathic PAH. The patients were classified into two groups as the deceased (D) and the survived (S). A set of data was collected for each patient, including gender, age, weight, height, BMI (kg/m2), World Health Organization functional class (WHO FC), brain natriuretic peptide (BNP), hemoglobin, the presence of atrial fibrillation (AF), 6-minute walking distance (6MWD), echocardiographic and hemodynamic parameters. Results: The mean follow-up period was 33.7 months (maximum: 128 months), 38 deaths (48.7%) were noted. The two groups were found to be similar in terms of gender, age, and the presence of AF. The median BNP level in group D was significantly higher than that in group S (p<0.001). Baseline WHO FC III-IV was significantly more common in group D than that in group S (89.5% vs 57.5%, p=0.003). Group D had significantly lower BMI and 6MWD compared to those in group S (p<0.001 and p=0.017, respectively). Multivariate logistic regression analysis showed that BMI [Odds ratio (OR)=0.632, 95% confidence interval (CI)=0.478-0.837, p=0.001] and 6MWD (OR=0.981, 95% CI=0.970-0.993, p=0.002) were independent predictors of mortality in this cohort. The receiver operating characteristic curve analysis was performed to assess the utility of BMI as a predictor of mortality. The optimal BMI cut-off was 24.25 kg/m2, with 60.5% sensitivity and 82.5% specificity (area under the curve=0.759, 95% CI=0.654-0.864, p<0.001) and thepatients with a BMI of ≤24.25 had worse prognosis based on the Kaplan Meier analysis survival curves (log-rank p<0.004). Conclusion: BMI seems to be linearly but inversely related to all-cause mortality among patients with idiopathic PAH.