Table I.

Characteristics of studies included in the present meta-analysis.

First author (ref.)	Year	Country	Ethnicity	Study design	Case number	Duration of intervention	Frequency of sessions	Main outcome measures	Quality scores
Corner et al (22)	1996	UK	Caucasian	RCT	11	3–6 weeks	Weekly	Visual analog scales, hospital anxiety and depression scale	30
Bredin et al (23)	1999	UK	Caucasian	RCT	51	3–8 weeks	Weekly	Visual analog scales, hospital anxiety and depression scale	26
Hately et al (8)	2003	UK	Caucasian	Cohort study	30	4–6 weeks	Weekly	Visual analog scales	25
Li (24)	2003	China	Asian	Cohort study	38	6 months	6 months	Pulmonary function, quality of life	21
Ye et al (17)	2004	China	Asian	Cohort study	52	6 months	3 months	Pulmonary function, quality of life	22
Pan et al (15)	2005	China	Asian	Cohort study	82	1–6 months	6 months	Pulmonary function, quality of life	20
Shi (16)	2006	China	Asian	Cohort study	48	6 months	3 months	Pulmonary function, quality of life	23
Zhou et al (25)	2012	China	Asian	Cohort study	86	1 week	1 week	Pulmonary function	22

RCT, randomized controlled trial.