Table 3.

Risk of bias

Study	Type of bias; risk
	Sequence generation	Allocation concealment	Incomplete outcome data	Blinding
Ahmed et al.22	Unclear	High	High	High
Khan et al.21	Unclear	High	High	High
Bali et al.20	High	High	High	High
Tokac et al.19	Unclear	Low	High	High
Arslan et al.18	Unclear	Low	High	High
Bessa17	Low	Low	Unclear	Low
Ates et al.16	Unclear	Low	High	High
Can et al.15	Unclear	Low	High	High
Ersoy et al.14	High	High	High	High
Pooled data	Low 1	Low 5	Low 0	Low 1