“…12 of 31 studies compared SpA cases with cases of other rheumatic diseases, such as rheumatoid arthritis (RA), osteoarthritis (OA) and gout. 7 studies analyzed the dynamic alterations in metabolic profiles in SpA patients before and after treatment (Gao et al, 2008;Kapoor et al, 2013;Nanus et al, 2015;Butbul et al, 2020;Bogunia-Kubik et al, 2021;Funk and Becker, 2021;Gupta et al, 2021;Ou et al, 2021). Regarding the metabolomic analysis in different subtypes of SpA, 13 studies included AS patients (Gao et al, 2008;Fischer et al, 2012;Jiang et al, 2013;Chen et al, 2015;Shao et al, 2016;Wang et al, 2016;He et al, 2019;Bogunia-Kubik et al, 2021;Eryavuz Onmaz et al, 2021;Lv et al, 2021;Onmaz et al, 2021;Ou et al, 2021).…”