Table 2 Risk of bias of studies included in this meta-analysis
Study | Random sequence generation | Allocation concealment | Blinding of participants, personnel | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other sources of bias |
|---|---|---|---|---|---|---|---|
Abbasnezhad 2016 [23] | Low risk; computer-generated blocked randomization list with a block size of 6 | Low risk; quote "all the participants, researchers, and the physician were blind to the allocations using the random codes" | Low risk, double-blind | Low risk, double-blind | Low risk, quote "All analyses were done on the intention-to-treat population" | Low risk, all prespecified outcomes were reported | Low risk |
Khalighi Sikaroudi 2020 [24] | Low risk; randomization was performed by using the online site www. sealedenvelope.com | Low risk; quote "For performing the concealment in the randomization process, dedicated codes were used on the pharmaceutical sheets, which were generated by the software." | Low risk, double-blind | Low risk, double-blind | Low risk, intention-to-treat analysis | Low risk, all prespecified outcomes were reported | Low risk |
El Amrousy 2018 [25] | Low risk; quote "computer-generated random numbers using a random block size of 6" | Low risk; quote "Allocation concealment was done by sequentially numbered sealed opaque envelopes." | Low risk; participants and treating staff were blinded to the treatment group. | Low risk; all outcome assessors were blinded to the treatment group | Low risk, complete outcome | Low risk, all prespecified outcomes were reported | Low risk |
Jalili 2016 [26] | Unclear; the author reported that participants were randomly assigned to different groups but did not mention how the random sequence was generated | Low risk; randomization was provided in sealed opaque envelopes with successive numbers. | Low risk; all participants and researchers were blinded to the treatment group. | Unclear; insufficient information | Low risk, intention-to-treat analysis | Low risk, all prespecified outcomes were reported | Low risk |