Table 2.

Risk of bias assessment in included studies

Bias	Authors’ judgment	Support for judgment
Fallah Huseini et al.
Random sequence generation (selection bias).	Unclear	No randomization method described
Allocation concealment (selection bias)	Low risk	The medications were placed in two boxes, and no difference could be detected.
Blinding of participants and personnel (performance bias)	Low risk	Double-blind
Blinding of outcome assessment (detection bias).	low risk	Double-blind
Incomplete outcome data (attrition bias).	Low risk	No loss
Selective reporting (reporting bias).	Unclear	Not found
Barghamdi et al.
Random sequence generation (selection bias).	Unclear	No randomization method was described.
Allocation concealment (selection bias)	Unclear	The method of concealment was not described in sufficient detail to allow a definite judgment.
Blinding of participants and personnel (performance bias)	Low risk	Double-blind
Blinding of outcome assessment (detection bias).	Low risk	Double-blind
Incomplete outcome data (attrition bias).	Low risk	No loss
Selective reporting (reporting bias).	High risk	LDL, HDL, cholesterol and triglyceride not reported
Yaghobi et al.
Random sequence generation (selection bias).	Low risk	Randomized selecting the A and B codes by the patient and recording in the file
Allocation concealment (selection bias)	Low risk	The medications were placed in two boxes, and no difference could be detected.
Blinding of participants and personnel (performance bias)	Low risk	Double-blind
Blinding of outcome assessment (detection bias).	Low risk	Double-blind
Incomplete outcome data (attrition bias).	Low risk	Minimal loss
Selective reporting (reporting bias).	High risk	HbA1c not reported
Li et al.
Random sequence generation (selection bias).	Unclear risk	No randomization method described
Allocation concealment (selection bias)	Unclear risk	The concealment method has not been described in sufficient detail to allow us to reach an accurate conclusion.
Blinding of participants and personnel (performance bias)	Unclear risk	Not mentioned
Blinding of outcome assessment (detection bias).	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias).	Unclear risk	Not mentioned
Selective reporting (reporting bias).	Unclear risk	The protocol’s database was not found.