Table 5.

Methodologic quality assessment of non-randomized clinical studies

First author	Year	Domain
		1	2	3	4	5	6
El Shenawy et al. [37]	2015	Low	Low	Unclear	High	Low	Low
Othman et al. [44]	2016	High	High	High	High	Low	Unclear

Domain 1: Selection bias caused by inadequate selection of participants; Domain 2: Selection bias caused by inadequate confirmation and consideration of confounding variable; Domain 3: Performance bias caused by inadequate measurement of intervention (exposure); Domain 4: Detection bias caused by inadequate blinding of outcome assessment; Domain 5: Attrition bias caused by inadequate handling of incomplete outcome data; Domain 6: Reporting bias caused by selective outcome reporting