Comparison of Functional Capacity and Symptoms of COPD Patients with and without Pulmonary Hypertension

Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD) associated with a decrease in the survival rate of patients with COPD. Our aim was to investigate whether PH impairs the functional capacity and symptoms in patients with COPD. In addition, we aimed to evaluate the correlation between the functional capacity and symptoms score in patients with COPD.

This prospective cross-sectional study enrolled 64 patients with moderate to severe COPD, prospectively. All patients underwent the pulmonary function test, echocardiography, 6-minute walk test (6MWT), and cardiopulmonary exercise testing (CPET). We applied the modified Medical Research Council (mMRC) dyspnea scale and COPD Assessment Test (CAT) to all patients. The mean pulmonary arterial pressure (mPAP) >30 mmHg with echocardiography was considered as PH. The patients were grouped according to the presence of PH as COPD-PH (n=30) and COPD-nonPH (n=34).

Hospitalization rate was higher in the COPD-PH group than in the COPD-nonPH group (p=0.006). The 6MWT results were lower in the COPD-PH group compared to the COPD-nonPH group (325±61 m vs. 354±46 m, respectively, p=0.025). In the COPD-PH group, the maximum oxygen consumption (VO_2max) was lower, but the difference did not reach statistical significance (p=0.118). Although the maximum load and minute ventilation were lower in the COPD-PH group, the end-tidal pressure of CO₂ (PETCO₂) was higher (p=0.033, p=0.036, and p=0.009, respectively). However, the CAT score and mMRC were similar between the groups (p=0.405 and p=0.238, respectively).

An elevated PAP in patients with COPD limits the exercise capacity. Using CPET in the functional evaluation of patients with COPD may be beneficial in the early detection of PH.