2.3 Data extraction
Inclusion and exclusion criteria were defined to determine the selection of clinical studies. References of all included articles were manually examined and added to our electronic citation manager to ensure that all pertinent published works had been identified. With no prior knowledge of the authors or results of the selected publications, 2 reviewers (Cao Z and Ling Y) rated the clinical and methodological quality of each study using a standardized scoring system independently after acquiring full texts of the studies. Studies that did not rate above a quality score threshold were excluded from data extraction.