Effects of Preoperative HbA1c Levels on the Postoperative Outcomes of Coronary Artery Disease Surgical Treatment in Patients with Diabetes Mellitus and Nondiabetic Patients: A Systematic Review and Meta-Analysis

Table 2

Risk of bias for included studies.

No.	Included studies	①	②	③	④	⑤	⑥	⑦	⑧	Overall score
1	Jin 2017	1	0	1	1	1	1	0	0	5
2	Andrzej 2014	1	1	0	1	1	0	1	1	6
3	Balachundhar 2014	1	1	0	1	1	1	0	0	5
4	Brooke 2016	1	1	1	1	1	0	0	0	5
5	Francesco 2018	1	0	1	1	1	1	0	0	5
6	Jacek 2015	1	1	0	1	1	1	1	1	7
7	Jeanette 2016	1	0	1	1	1	0	1	1	6
8	Mona 2017	1	1	1	1	1	0	0	0	5
9	Orit 2013	1	1	0	1	1	1	0	0	5
10	Sato 2010	1	1	1	1	1	0	0	0	5
11	Seyed 2012	1	1	1	1	1	1	1	1	8
12	Michael 2008	1	1	1	1	1	0	1	1	7
13	Santos 2015	1	1	1	1	1	0	0	0	5
14	Gilles 2009	1	1	1	1	1	0	1	1	7
15	Nyström 2015	1	1	1	1	1	0	1	1	7
16	Tsuruta 2011	1	1	1	1	1	0	1	1	7
17	Knapik 2010	1	1	1	1	2	0	0	0	6
18	Matsuura 2009	1	1	1	1	1	0	1	1	7
19	Arslan 2015	1	0	1	1	1	1	0	0	5
20	Pradeep 2017	1	1	1	1	1	1	0	0	6
21	Stephen 2013	1	1	1	1	1	1	1	0	7
22	Michael 2008	1	1	1	1	1	0	0	0	5
23	Islam 2015	1	1	1	1	1	1	1	0	7

^①Representativeness of the exposed cohort. ^②Selection of the nonexposed cohort. ^③Ascertainment of exposure. ^④Demonstration that the outcome of interest was not present at the start of the study. ^⑤Comparability of cohorts on the basis of the design or analysis. ^⑥Assessment of outcome. ^⑦Follow-up was long enough for outcomes to occur. ^⑧Adequacy of follow-up of cohorts.