Metagenomic analysis of gut microbiome and spondyloarthropathy: A systematic review

Table 2 Risk of bias analysis of the selected studies

Ref.	Risk of bias
	Selection				Comparability	Outcome
	Is the exposed cohort truly representative of the population?	Was the nonexposed cohort chosen from the same group of people as the exposed cohort?	Did the determination of exposure originate from secure records?	Was the desired outcome missing at the beginning of the study?	Was comparability of cohorts done on the basis of the design or analysis?	Was the evaluation of the outcome based on a record linkage or an independent blind assessment?	Was the follow-up period long enough for results to materialise?	Was the cohort follow-up sufficient (subjects lost to follow-up < 20%)?
Zhou et al[26] 2020	+	+	+	-	+	+	+	+
Huang et al[33] 2020	+	+	-	+	+	+	+	+
Yin et al[31] 2020	+	+	+	-	+	+	+	+
Li et al[32], 2023	+	+	-	+	-	+	-	+
Wen et al[34], 2017	+	+	+	-	+	+	+	+

“+” indicates studies satisfying the domain item analysed; “-“ indicates studies lacking the domain item analysed.