Fig. 1From: The effect of acupuncture on exercise capacity in patients with COPD is mediated by improvements of dyspnea and leg fatigue: a causal mediation analysis using data from a randomized controlled trialAssumed causal graph The relationships between intervention (A), mediators (M1 and M2), outcome (Y), and covariates (C) that were assumed in this study are shownBack to article page