Pulmonary Arterial Hypertension and Obesity†

Purpose: To examine the association between obesity and pulmonary arterial hypertension (PAH). Methods: This retrospective case-control study consisted of patients with PAH (N=207) and controls seen at a pulmonary clinic for reasons other than PAH (N=965). All patients were evaluated between 1992 and 2006 at Mayo Clinic in Jacksonville, Florida. Obesity was defined as body mass index (BMI) of 30 kg/m or higher; class II obesity was defined as a BMI between 35.0 and 39.9 kg/m, and class III obesity was defined as a BMI of 40.0 kg/m or higher. Results: Obesity was present in 63 patients with PAH (30%) and 290 controls (30%). Class II or III obesity was present in 34 patients with PAH (16%) and 103 controls (11%), while class III obesity was present in 16 patients with PAH (8%) and 36 controls (4%). After adjustment for age, sex, and thyroid disease in logistic regression analysis, an association between obesity and PAH was not evident (odds ratio [OR], 0.97; P=.87), however non-statistically significant trends were observed toward an association between PAH and class II or III obesity (OR, 1.40; P=.14) and class III obesity (OR, 1.70; P=.11). Conclusions: Our findings do not indicate an association between PAH and obesity in WHO diagnostic group 1 patients. However trends were observed toward more severe class II and III obesity in PAH patients compared to controls, and this requires further study in larger samples.