Quality assessment

Risk of bias of the included articles was assessed using criteria specified in the Cochrane Handbook for Systematic Reviews of Intervention 5.0.2. Specifically, it included: (I) generation of random sequence (whether a random number table or other random method was utilized for grouping of research objects); (II) allocation concealment (whether there was randomization and whether the randomization remained concealed); (III) subject blinding (whether study subjects knew whether they were in the experimental group and which group they were in); (IV) outcome assessor blinding (whether the researcher or outcome assessor knew the group status of subjects); (V) data integrity (whether data were complete and whether there were missing data); (VI) selective reporting (whether there was selective reporting); and (VII) other biases. If data extracted by the two researchers were inconsistent, the inconsistency was discussed and resolved. If no consensus was achieved, a third researcher was consulted.