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

Table 4 GRADE evidence quality evaluation of outcomes

Outcome	Risk of Bias^①	Inconsistency^②	Publication Bias^⑤	Level of Evidence
ΔFVC	− 1	-2	0	Extremely low
Δ%FVC	− 1	-2	-1	Extremely low
Δ6MWT	− 1	-2	0	Extremely low
Δ%DLco	− 1	-1	0	Low
at least one side effects	− 1	0	-1	Low
severe side effects	− 1	0	-1	Low
gastrointestinal effects	− 1	0	-1	Low
skin effects	− 1	0	0	Moderate
mortality rates	− 1	0	0	Moderate

− 1 (Downgrade by 1 level); 0 (no downgrade)
①Limitations in study design or execution; Most of the information comes from medium and high risk studies
②The effect size and direction of each study were inconsistent/confidence interval overlap was small/heterogeneity test P-value was small, I² > 50%
③Indirect evidence
④Insufficient sample size/The confidence interval is not narrow enough
⑤Funnel plot asymmetry/suspected large publication bias

ISSN: 1471-2466