Effect of pulmonary hypertension on exercise tolerance in patients with COPD: a prognostic systematic review and meta-analysis

Abstract

Background: Pulmonary hypertension (PH) is a frequent complication in patients with COPD.

Objective: To determine if, in patients with COPD, the presence of PH decreases exercise tolerance.

Methods: We included studies that analysed exercise tolerance using a cardiopulmonary exercise test (CPET) in patients with COPD with PH (COPD-PH) and without PH (COPD-nonPH). Two independent reviewers analysed the studies, extracted the data and assessed the quality of the evidence.

Results: Of the 4915 articles initially identified, seven reported 257 patients with COPD-PH and 404 patients with COPD-nonPH. The COPD-PH group showed differences in peak oxygen consumption (V'_O2peak ), -3.09 mL·kg^-1·min^-1 (95% CI -4.74 to -1.43, p=0.0003); maximum workload (W_max), -20.5 W (95% CI -34.4 to -6.5, p=0.004); and oxygen pulse (O₂ pulse), -1.24 mL·beat^-1 (95% CI -2.40 to -0.09, p=0.03), in comparison to the group with COPD-nonPH. If we excluded studies with lung transplant candidates, the sensitivity analyses showed even bigger differences: V'_O2 , -4.26 mL·min^-1·kg^-1 (95% CI -5.50 to -3.02 mL·kg^-1·min^-1, p<0.00001); W_max, -26.6 W (95% CI -32.1 to -21.1 W, p<0.00001); and O₂ pulse, -2.04 mL·beat^-1 (95% CI -2.92 to -1.15 mL·beat^-1, p<0.0001).

Conclusion: Exercise tolerance was significantly lower in patients with COPD-PH than in patients with COPD-nonPH, particularly in nontransplant candidates.