A systematic review and meta-analysis based on 92 observational studies involving nearly 12,000 participants shows that patients with rheumatic diseases have a lower αdiversity of the gut microbiome compared to healthy controls.
The researchers searched PubMed, Embase and the Cochrane Library for observational studies assessing associations between the gut microbiome and rheumatic disease.
Of the 92 included studies (with 11,998 participants), 68 provided data on α diversity. Overall, it was consistently lower in rheumatic diseases (observed species: standardized mean difference (SMD) -0.36 (95% CI -0.63 to -0.09); Chao1: SMD -0.57 (95 % CI -0.88 to -0.26), Shannon Index: SMD -0.33 (95% CI -0.48 to -0.17), Simpson Index: SMD -0.32 (95 % CI -0.49 to -0.14)). However, when specific rheumatic diseases were investigated, a decrease was only observed in RA (observed species: SMD -0.51 (95% CI -0.78 to -0.24); Shannon Index: SMD -0.31 (95% CI -0.49 to -0.13) Simpson Index: SMD -0.31 (95% CI -0.54 to -0.08)), SLE (Chao1: SMD -1.60 (95% CI -2.54 to -0.66), Shannon Index: SMD -0.63 (95% CI -1.08 to -0.18)), Gout (Simpson Index: SMD – 0.64 (95% CI -1.07 to -0.22)) and fibromyalgia (Simpson index: SMD -0.28 (95% CI -0.44 to -0.11)), while a increase was observed for scleroderma (Shannon index: SMD 1.25 (95% CI 0.09 to 2.41)). Statistically significant differences in β diversity have been reported in ankylosing spondylitis and IgG4-related disorders. Little evidence was found for disease-specific changes in the presence of gut microbes. However, a depletion of anti-inflammatory butyrate-producing microbes (Faecalibacterium) and an enrichment of pro-inflammatory microbes (Streptococcus) was observed in both RA, Sjögren and SLE.
Wang Y, Wei J, Zhang W, et al. Gut dysbiosis in rheumatic diseases: A systematic review and meta-analysis of 92 observational studies. EBioMedicine. 2022;80:104055.