Inclusion and exclusion criteria

Inclusion and exclusion criteria were recorded following PRISMA guidelines presented in the form of a PRISMA flow diagram (Fig. 1 ). Briefly, the retrieved literature was imported into Endnote software (v. × 9.0) and screened for exclusion criteria. First, duplicate literature was removed by Endnote, and then obviously inappropriate ones were eliminated based on the title and abstract. Finally, remaining inappropriate entries were eliminated by reading the full articles. The exclusion criteria for articles were non-English studies, entries with only an abstract, those with no relevant topic, and studies containing no useful or duplicated data from previously published studies. The inclusion criteria are articles reporting confirmed SARS-CoV-2 positive patients, and studies presenting original data as well as clear and precise end-point outcomes.

PRISMA flowchart of literature search strategy.