Table 1.

Results of the Newcastle–Ottawa quality assessment

	Study	Study design	Selection				Comparability	Exposure/Outcome			Result
			1	2	3	4	1/2	1	2	3
1	Aoki et al. [39]	Retrospective cohort study with post-hoc case–control analysis	1	1	1	1	0	1	1	1	7
2	Barnard et al. [28]	Retrospective cohort	1	1	1	1	0	1	1	1	7
3	Barnard et al. [40]	Retrospective cohort	1	1	1	1	0	1	1	1	7
4	Beck et al. [29]	Retrospective cohort	1	1	1	1	0	1	1	1	7
5	Beck et al. [1]	Retrospective cohort	1	1	1	1	0	1	1	1	7
6	Chen et al. [41]	Retrospective cohort	1	1	1	1	0	1	1	1	7
7	Chia et al. [30]	Retrospective cohort	1	1	1	1	0	1	1	1	7
8	Chiang et al. [31]	Retrospective cohort	1	1	1	1	0	1	1	1	7
9	Claesson et al. [32]	Retrospective cohort	1	1	1	1	0	1	1	1	7
10	Cureton et al. [23]	Retrospective cohort	1	1	1	1	0	1	1	1	7
11	David et al. [19]	Randomized controlled trial	1	0	1	1	0	1	1	1	6
12	Deasy et al. [24]	Retrospective cohort	1	1	1	1	0	1	1	1	7
13	Di Bartolomeo et al. [6]	Prospective population-based study	1	1	1	1	0	1	1	1	7
14	Djarv et al. [35]	Retrospective cohort	1	1	1	1	0	1	1	1	7
15	Duchateau et al. [33]	Retrospective cohort	1	1	1	1	0	1	1	1	7
16	Escutnaire et al. [36]	Retrospective cohort	1	1	1	1	0	1	1	1	7
17	Evans et al. [27]	Retrospective cohort	1	1	1	1	0	1	1	1	7
18	Faucher et al. [21]	Retrospective cohort	1	1	1	1	0	1	1	1	7
19	Fukuda et al. [37]	Retrospective cohort	1	1	1	1	0	1	1	1	7
20	Gräsner et al. [2]	Retrospective cohort	1	1	1	1	0	1	1	1	7
21	Huber-Wagner et al. [20]	Retrospective cohort	1	1	1	1	0	1	1	1	7
22	Irfan et al. [34]	Retrospective cohort	1	1	1	1	0	1	1	1	7
23	Israr et al. [42]	Retrospective cohort	1	1	1	1	0	1	1	1	7
24	Javaudin et al. [46]	Retrospective cohort	1	1	1	1	0	1	1	1	7
25	Jun et al. [47]	Retrospective cohort	1	1	1	1	0	1	1	1	7
26	Kitamura et al. [26]	Retrospective cohort	1	1	1	1	0	1	1	1	7
27	Lin et al. [25]	Retrospective cohort	1	1	1	1	0	1	1	1	7
28	Lockey et al. [3]	Retrospective cohort	1	1	1	1	0	1	1	0	6
29	Lu et al. [43]	Retrospective cohort	1	1	1	1	0	1	1	1	7
30	Moriwaki et al. [22]	Retrospective cohort	1	1	1	1	0	1	1	1	7
31	Pickens et al. [17]	Retrospective cohort	1	1	1	1	0	1	1	1	7
32	Stockinger et al. [16]	Retrospective cohort	1	1	1	1	0	1	1	1	7
33	ter Avest et al. [44]	Retrospective cohort	1	1	1	1	0	1	1	1	7
34	Tsutsumi et al. [38]	Retrospective cohort	1	1	1	1	0	1	1	1	7
35	Willis et al. [18]	Retrospective cohort	1	1	1	1	0	1	1	1	7
36	Yamamoto et al. [45]	Prospective observational study with post hoc analysis	1	1	1	1	0	1	0	1	6

1 one star awarded for criterion, 0 no star awarded for criterion. The right-most column shows the total number of stars awarded per included study