Safety of the 6-min walk test in adults with severe asthma

This study aimed to assess the safety of 6-min walk test (6MWT) in people with severe asthma compared with non-severe asthma, chronic obstructive pulmonary disease (COPD), and healthy controls. Secondly, we sought to compare 6MWT outcomes between adults with severe asthma receiving monoclonal antibody therapy (mAb) or not.

A total of 403 participants (severe asthma n = 175; non-severe asthma n = 64; COPD n = 99; controls n = 65) underwent a cross-sectional multidimensional assessment that included a 6MWT. Groups were compared regarding adverse events, limiting factors, and physiological responses during the 6MWT.

Participants with severe asthma, mostly female (65 %), with an average (median [quartile1, quartile3]) age of 60 [45,69] years and BMI of 31 [26,37] kg/m² showed no adverse events during the 6MWT, irrespective of mAb treatment. The proportion of participants who rested during 6MWT was similar between participants with severe (10 %) and non-severe asthma (9 %), but lower than those with COPD (23 %). The severe asthma group experienced greater breathlessness from the 6MWT compared with non-severe asthma and controls (p < 0.001). Fewer participants with severe asthma had SpO₂ decrease to <85 % during the test compared with COPD (3 % vs 14 %, p < 0.05). No differences in the 6MWT distance were observed between mAb-treated or non-treated severe asthma participants (p = 0.13). Those receiving mAb therapy did not report respiratory limitations during the test.

The 6MWT is safe for adults with severe asthma when pre-bronchodilation is provided and SpO₂ <85 % is used as a stopping criterion. Participants treated or not with mAb achieved comparable 6MWT distances.