Study selection

The title and abstract of the articles were independently evaluated based on the inclusion and exclusion criteria by two investigators (WJ and GY). Subsequently, the full text targeted articles were retrieved and accessed for eligibility to be included. The reason for the articles’ exclusion was documented. The process of study selection, data extraction and quality appraisal were conducted independently by two investigators (WJ and GY). Any disagreements or differences in opinion between the two researchers (WJ and GY) were handled through discussions and consensus, followed by a third researcher’s independent opinion (NAMT). The three researchers (WJ, GY and NAMT) would need to reach an agreement before making a final decision.