Efficacy of N-acetylcysteine plus pirfenidone in the treatment of idiopathic pulmonary fibrosis: a systematic review and meta-analysis

Table 3 RCT risk assessment using the Cochrane collaboration risk of bias tool

Reference	Random Sequence Generation^①?	Allocation Concealment^②?	Blinding of Participants and Personnel^③?	Incomplete Outcome Data^④?	Selective Reporting^⑤?	Other Biases^⑥?	Risk of Bias
Sakamoto (2021) [18]	+	+	-	+	+	+	High
Behr (2016) [19]	+	+	+	+	+	+	Low
Wen (2019) [22]	+	-	-	-	+	-	High
Zhou (2021) [23]	+	-	-	+	+	+	High
Zhao (2023) [24]	+	-	-	+	+	+	High

①Describe the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups
②Describe the method used to conceal the allocation sequence in sufficient detail to determine whether intervention allocations could have been foreseen in advance of, or during, enrolment
③Describe all measures used, if any, to blind study participants, personnel and outcome assessors from knowledge of which intervention a participant received
④Describe the completeness of outcome data for each main outcome, including attrition and exclusions from the analysis
⑤State how the possibility of selective outcome reporting was examined by the review authors, and what was found
⑥State any important concerns about bias not addressed in the other domains in the tool. The other bias mainly refers to the existence of at least one of the important sources of bias, such as the existence of potential sources of bias related to the specific study design used; Claims of deception; or there are some other problems

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