Previous studies have found dysregulated serum irisin in COPD, suggesting that irisin may be involved in the pathogenesis of COPD and its skeletal muscle comorbidity (Greulich et al., 2014; Ijiri et al., 2015; Boeselt et al., 2017; Sugiyama et al., 2017; Kubo et al., 2019; Zhang and Sun, 2021). This evidence concerns the gene FNDC5 and chronic obstructive pulmonary disease.