Study characteristics
Finally, 14 retrospective cross-sectional studies regarding different population which can be concluded from patients’ origin were suitable for this meta-analysis[14-27]: four multi-center studies[19-21, 27] and ten single-center studies[14-18, 22-26]. All the eligible studies were from China and published in 2020. Due to the instinct design of this meta-analysis, no randomized or non-randomized controlled trial was eligible for this meta-analysis. Characteristics of eligible studies were shown in Table 1.