Table 4.

Quality assessment of included retrospective studies using AHRQ criteria

Author	Item 1	Item 2	Item 3	Item 4	Item 5	Item 6	Item 7	Item 8	Item 9	Item 10	Item 11	Total quality score out of 11
Innes et al.35	Yes	Unclear	Yes	Yes	No	Yes	No	No	Unclear	Yes	No	5
Ludwig et al.36	Yes	Yes	Yes	Yes	No	Yes	Yes	No	No	Yes	Yes	8

The agency of healthcare research and quality (AHRQ) criteria