Analysis of the risk of bias among the included studies
| Study | Random sequence generation (selection bias) | Allocation concealment (selection bias) | Blinding (participants and personnel; performance bias) | Blinding (outcome assessment; detection bias) | Incomplete outcome data (attrition bias) | Selective reporting (reporting bias) |
|---|---|---|---|---|---|---|
| Ayoya et al. (17), (18) | Yes | Yes | Yes | Yes | Yes | Unknown |
| Berger et al. (19) | Unknown | Unknown | Yes | Yes | Yes | Unknown |
| Boivin et al. (20) | Unknown | Unknown | Unknown | Unknown | Yes | Unknown |
| Bradfield et al. (21) | Unknown | Yes | Yes | Yes | Unknown | Unknown |
| Charoenlarp (22) | Unknown | Unknown | Yes | Yes | Yes | Unknown |
| Charoenlarp et al. (23) | Unknown | Unknown | Yes | Yes | Unknown | Unknown |
| Chwang et al. (24) | Unknown | Unknown | Unknown | Yes | Unknown | Unknown |
| de Silva et al. (25) | Unknown | Unknown | Yes | Yes | Yes | Unknown |
| Fallahi et al. (26) | Unknown | Unknown | Yes | Yes | Yes | Unknown |
| Gebreselassie (27) | Yes | Yes | Yes | Yes | Yes | Yes |
| Gopaldas et al. (28)– (31) | Unknown | Unknown | Yes | Yes | Unknown | Unknown |
| Greisen (32) | No | Unknown | Unknown | Yes | Yes | Unknown |
| Harvey et al. (33) | Unknown | Unknown | Unknown | Unknown | Yes | Unknown |
| Kashyap et al. (34) | Unknown | Unknown | Unknown | Unknown | Yes | Unknown |
| Konofal et al. (35) | Yes | Unknown | Yes | Yes | Yes | Unknown |
| Latham et al. (36) | Unknown | Unknown | Unknown | Yes | Yes | Unknown |
| Lawless et al. (37) | Yes | Yes | Yes | Yes | Unknown | Unknown |
| Nchito et al. (38)– (40) | Unknown | No | Unknown | Yes | No | Unknown |
| Paracha et al. (41) | Unknown | Unknown | Unknown | Yes | Yes | Unknown |
| Perrone et al. (42) | Unknown | Unknown | Unknown | Yes | Yes | Unknown |
| Pollitt et al. (43), (44) | Unknown | Unknown | Yes | Yes | No | No |
| Powers et al. (45) | Unknown | Unknown | Yes | Yes | Yes | Unknown |
| Richard et al. (46) | Yes | Yes | Yes | Yes | Yes | Unknown |
| Rico et al. (47)– (50) | Yes | Unknown | Yes | Yes | Yes | Yes |
| Rosales et al. (51) | Yes | Yes | Yes | Yes | Yes | Unknown |
| Sen et al. (52), (53) | No | No | No | No | Unknown | Unknown |
| Sen et al. (54) | Unknown | Unknown | No | No | Unknown | Unknown |
| Seshadri et al. (study 1) (28), (55) | Unknown | Unknown | No | No | Unknown | Unknown |
| Seshadri et al. (study 2) (28), (55) | Yes | Unknown | Unknown | Unknown | Unknown | Unknown |
| Seshadri et al. (study 4) (28) | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown |
| Soemantri et al. (56) | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown |
| Sungthong et al. (57), (58) | Yes | Yes | Unknown | Unknown | Yes | Unknown |