Table 2 Risk of bias assessment of individual studies
Author, year | Appropriate question | Randomi-zation | Adequate Concealment method | Adequate blinding | Similar treatment in groups at start | Only difference is investigated treatment | Standardized, outcome measurement | Drop Outs before study completed | Intention to treat analysis | Overall rating of risk of bias |
|---|---|---|---|---|---|---|---|---|---|---|
Star, 2000 [27] | Yes | Yes | No | Can’t say | Yes | Yes | Yes | 0% | Yes | Acceptable (+) |
Yamamoto, 2004a [28] | No | Can’t say | No | Can’t say | Can’t say | Can’t say | Can’t say | Can’t say | Can’t say | Unacceptable |
Vu, 2012 [22] | Yes | Yes | Yes | Can’t say | Yes | Yes | Yes | 1.9% | Yes | High quality (++) |
Abdelnour, 2012b [29] | Yes | Can’t say | No | Can’t say | Can’t say | Can’t say | Can’t say | Can’t say | Can’t say | Low quality (-) |
Ruiz de Adana, 2015 [30] | Yes | Yes | No | No | Yes | Yes | Yes | 0% | Yes | Acceptable (+) |
Gerards, 2016 [20] | Yes | Yes | Yes | Yes | Can’t say | Can’t say | Yes | 15% | Yes | Acceptable (+) |
Grommesh, 2016 [31] | Yes | Yes | No | No | Yes | Yes | Yes | 15% | Yes | Acceptable (+) |
Hitchings, 2016 [21] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 0% | Yes | High quality (++) |
Lakhani, 2017 [17] | Yes | Yes | No | No | Yes | Yes | Yes | Control 26% Intervention 28% | Yes | Acceptable (+) |
Radhakutty, 2017 [16] | Yes | Yes | Yes | Can’t say | Yes | Yes | Yes | 4% | Yes | High quality (++) |
Seelig, 2017 [23] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 15% | Yes | High quality (++) |
Gerards, 2018 [32] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 0% | Yes | High quality (++) |
Aberer, 2019 [33] | Yes | Yes | Can’t say | Can’t say | Yes | Yes | Yes | 0% | Yes | Acceptable (+) |
Pernicova, 2020 [24] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Control 22% Intervention 27% | Yes | High quality (++) |
Ochola LA, 2020 [34] | Yes | Yes | No | No | Yes | Yes | Yes | Control 15% Intervention 35% | Yes | Acceptable (+) |
Hong JGS, 2021 [25] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Control 27% Intervention 29% | Yes | High quality (++) |
Battarbee AN, 2022 [26] | Yes | Yes | Can’t say | No | Yes | Can’t say | Yes | Control 0% Intervention 2% | Yes | Acceptable (+) |