Criteria for Study Identification and Selection

Two authors identified and selected original studies based on the eligibility criteria, and conducted an in-depth literature review of studies that might meet the requirements (Figure 1). Two authors (Lu Yao and Lin Fengxia) analyzed and selected all the papers manually, independently, and simultaneously. Disagreement was resolved through joint assessment of the literature or by referring the controversial literature to a third person for decision until consensus was reached. Through electronic retrieval, 173 papers were identified. A total of 86 duplicate publications were excluded, which was rechecked by EndNote bibliography software. The remaining 87 papers were screened after reading their titles and abstracts, as well as the full text. Finally, after a comprehensive assessment of the eligibility criteria, 10 studies entered the next stage of review.

Literature screening process.