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

Background This study aimed to assess the safety of 6-minute 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. Methods 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. Results 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/m 2 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 SpO 2 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. Conclusion The 6MWT is safe for adults with severe asthma when pre-bronchodilation is provided and SpO 2 <85% is used as a stopping criterion. Participants treated or not with mAb achieved comparable 6MWT distances.