Comparison of maximal exercise capacity between patients with COPD from Brazil and United Kingdom

Abstract

Background: Field exercise tests such as the incremental shuttle walking test (ISWT) have been used worldwide in order to assess exercise capacity of patients with chronic obstructive pulmonary disease (COPD). However, the responses to this test in patients from different world regions have not yet been compared.

Objectives: To compare the responses to the ISWT between patients with COPD from Brazil and United Kingdom (UK).

Methods: 20 patients with COPD from Brazil were matched to 20 patients from the UK concerning gender distribution, age, body mass index and FEV₁. All patients performed the ISWT during the baseline assessment for admission to a pulmonary rehabilitation program in their respective country. The total distance walked was recorded and heart rate (HR), oxygen saturation (SpO₂) and dyspnea score (Borg scale) were assessed before and after the test in both centers.

Results: In both groups, SpO₂ decreased and HR and dyspnea scores increased significantly after the test (p<0.05 for all). Brazilian patients walked farther and achieved higher% of their maximal predicted HR than patients from the UK (345±173 vs 209±116 meters [p=0.006] and 80±12 vs 64±10%pred [p<0.0001], respectively). The increase in dyspnea sensation after the test tended to be higher in the Brazilian group (4 [2-6] vs 2 [1-4], p=0.06).

Conclusions: Brazilian patients with COPD seem to walk more and achieve higher effort during the ISWT than patients from the United Kingdom. This is in line with previous data showing that patients from South America (especifically Brazil) are more active in daily life and have better functional exercise capacity in comparison to patients from Europe and United States.