Flowchart

Last update : 2020-06-02

Electronic databases
(n=16060, from PubMed)
Archives and curated websites
(n = 3670 from MedRxiv, ChinaXiv)
Other sources
(n = 22)

Records after duplicates removed
(n=13499)



Records screened
(n = 17191)


Records excluded
(n = 16845)

Full-text articles assessed for eligibility
(n = 346)


Full-text articles excluded:
(n = 215)

Randomized Controlled Trials
(n=17)

Quasi-experimental studies
(n=5)

Non-randomized studies (Observational Study)
(n=114)