Background: Pulmonary hypertension associated with COPD varies greatly among studies, and accounts for increased morbidity and mortality among patients with COPD. This study aims to evaluate prevalence of pulmonary hypertension, possible predictors and effect on exercise capacity.

Methods: 73 COPD patients were grouped into 2 groups according to presence of pulmonary hypertension. Assessment included full clinical history, mMRC dyspnea scale and COPD assessment test. Transthoracic echocardiography, cardiopulmonary exercise testing (CPET) using incremental treadmill exercises protocol. Results: 43 COPD patients (58.9%) suffered from pulmonary hypertension, 58.1% of them were males. COPD patients with pulmonary hypertension had significantly lower parameters of pulmonary function tests either pre or post-bronchodilator; significantly lower pH, PO2 and SO2 either before or after CPET. Mean pulmonary artery pressure had significant negative correlations with FEV1 (r= -0.27, p= 0.02), pre-test PaO2 (r= -0.38, p< 0.001), post-test PaO2 (r= -0.28, p= 0.01), predicted VO2 (r= -0.62, p< 0.001), predicted BR (r= -0.42, p< 0.001) and oxygen pulse (r= -0.48, p< 0.001). Predictors of pulmonary hypertension among COPD patients were oxygen saturation before the test (OR= 0.59, 95%CI= 0.39-0.90) and oxygen pulse (OR= 0.55, 95%CI= 0.35-0.87). Conclusion: pulmonary hypertension is negatively correlated with exercise capacity, specifically peak VO2 percent predicted. Predictors of pulmonary hypertension among COPD patients were oxygen saturation before the test and oxygen pulse.