Methods
A systematic search was conducted for randomised controlled trials
published between 1946 and May 2019 across major databases using the key
MeSH terminologies. The association between PEs and PI, LF and HRQOL
were extracted and categorized into positive, negative or no association
for analysing the data. A descriptive synthesis was conducted and the
association between PEs and PI, LF and HRQOL were reported.