Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a debilitating disease. The severity of airflow limitation alone is not strongly correlated with quality of life (QoL) and, therefore, exercise testing is employed to measure functional performance objectively, which is generally believed to correlate with QoL.

Objectives: Understand the relation between exercise capacity and quality of life.

Methods: Prospective study. Stable COPD patients were consecutively recruited. We analysed demographic, clinical, functional and exercise performance data. Patients answered symptoms and quality of life questionnaires - modified Medical Research Council (mMRC) dyspnoea scale, COPD Assessment Test (CAT), COPD Clinical Questionnaire (CCQ).

Results: 124 subjects - 13% female, mean age 66 ± 9years. Most patients were GOLD B or D (36% and 33%). Median FEV1 was 47%, (38-65%). Forty subjects (32%) had mMRC ≥ 2, CAT was ≥ 10 in 35% and CCQ ≥ 1.5 in 40% of patients. FEV 1 and hyperinflation, measured by IC/TLC, correlated with mMRC and CCQ but not with CAT. DLCO correlated better with mMRC and CCQ than CAT. The median peak VO2, in CPET, was 15.5 mL/min/kg (13.6-17.8 mL/min/kg). The 6MWD median was 479 meters (404-510 m), with median ΔSpO2 5% (3-9%). Patients with mMRC ≥ 2 had worse performance in both 6MWT and CPET - lower 6MWD, peak workload and peak VO2 and higher ΔSpO2 and ΔBorg. The 6MWD, peak workload and peak VO2 also correlated with quality of life (CAT and CCQ). Higher mMRC and CCQ were associated with dynamic hyperinflation, but not CAT.

Conclusion: Symptoms and QoL can estimate exercise performance.