Fig. 2

Alterations of α- and β-diversity of gut microbiome in ME/CFS patients A Outline of gut microbiome α- and β-diversity change from the 11 selected studies, denoted by Roman numerals I to XI. B Forest plots summarizing alpha-diversity of gut microbiome using the random-effects meta-analysis model. C List of gut microbiome β-diversity in gut microbiome of ME/CFS patients versus healthy controls. CI confidence interval, df degrees of freedom; I², I-square heterogeneity statistic, ME/CFS Myalgic encephalomyelitis/chronic fatigue syndrome, HC healthy control, N/A non-available, CCA Canonical correspondence analysis, BCD Bray–curtis dissimilarity, WUD Weighted UniFrac distance, UUD Unweighted UniFrac distance; DFA Discriminant function analysis. *P < 0.05 and **P < 0.01 ME/CFS patients compared to the healthy controls