Table 3.

Summary of the risk of bias assessment

Domain	Benic [2019] [29]	Gizani et al. [2016] [30]	Habib [2016] [31]	Kohar et al. [2015] [32]
1	Low	Low	Low	Unclear
2	Low	Unclear	Unclear	Unclear
3	Low	Low	Low	Unclear
4	Low	Low	Low	Unclear
5	Low	Low	Low	Low
6	Low	Low	Low	Low
7	Unclear	Unclear	Unclear	Unclear
Summary	Low	Low	Low	Unclear

Domains examined: 1: Random sequence generation 2: Allocation concealment, 3: Blinding of participants and personnel, 4: Blinding of outcome assessment, 5: Incomplete outcome data, 6: Selective outcome reporting, 7: Other potential threats to validity