PMC8071979_01
Selection of studies for the meta-analysis (Preferred Reporting Items for Systematic Reviews and Meta-Analyses).
10.1177_17534666211009407-fig1.jpg
PMC8071979_01_10.1177_17534666211009407-fig1.jpg
fig1-17534666211009407
The Newcastle-Ottawa quality assessment scale (NOS) checklist (Supplementary material Figure S1 online) was used to assess the quality of eligible studies.