Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Lung function
[74] RCT	709 Chinese people with COPD, with at least 2 exacerbations per year over 2 years	Lung function 12 months with carbocisteine 250 mg twice daily with placebo Absolute numbers not reported	P value not reported Reported as not significant		Not significant