COPD	Chronic obstructive pulmonary disease
HRQOL	Health-related quality of life
PR	Pulmonary rehabilitation
RCT	Randomized controlled trial
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses
BMI	Body mass index
SD	Standard deviation
GRADE	Grading of Recommendations Assessment, Development and Evaluation
6MWD	6 min walk distance
WMD	Weighted mean difference
CI	Confidence interval