Table 3. Quality assessment of included study.
| Author | Year | Selection | Comparability | Outcome | Number of stars |
|---|---|---|---|---|---|
| Bassig et al. (16) | 2014 | ★★★ | ★★ | ★ | 6 |
| Bijnens et al. (17) | 2015 | ★★ | ★★ | ★ | 5 |
| Bin et al. (18) | 2010 | ★★ | ★★ | ★ | 5 |
| De Felice et al. (19) | 2012 | ★★★★ | ★★ | ★ | 7 |
| Dioni et al. (20) | 2011 | ★★ | ★ | ★ | 4 |
| Eshkoor et al. (21) | 2011 | ★ | ★★ | ★ | 4 |
| Hou et al. (22) | 2012 | ★★ | ★★ | ★ | 5 |
| Hoxha et al. (23) | 2009 | ★★ | ★★ | ★ | 5 |
| Lee et al. (24) | 2017 | ★★★ | ★★ | ★ | 6 |
| Li et al. (25) | 2015 | ★★ | ★★ | ★ | 5 |
| Li et al. (26) | 2011 | ★★ | ★★ | ★ | 5 |
| Lin et al. (27) | 2017 | ★★★ | ★★ | ★ | 6 |
| Lin et al. (28) | 2013 | ★★ | ★★ | ★ | 5 |
| Ling et al. (29) | 2016 | ★★ | ★★ | ★★★ | 7 |
| McCracken et al. (30) | 2010 | ★★ | ★★ | ★★★ | 7 |
| Pavanello et al. (31) | 2010 | ★★ | ★★ | ★ | 5 |
| Pawlas et al. (32) | 2015 | ★★ | ★★ | ★★★ | 7 |
| Pieters et al. (33) | 2015 | ★★ | ★★ | ★ | 5 |
| Shan et al. (34) | 2014 | ★★★★ | ★★ | ★ | 7 |
| Walton et al. (35) | 2016 | ★★★ | ★★ | ★★★ | 8 |
| Ward-Caviness et al. (36) | 2016 | ★★★ | ★★ | ★★★ | 8 |
| Wong et al. (37) | 2014 | ★★ | ★★ | ★★★ | 7 |
| Wu et al. (38) | 2012 | ★★ | ★★ | ★ | 5 |
| Xia et al. (39) | 2015 | ★★★ | ★★ | ★★★ | 8 |
| Zota et al. (40) | 2015 | ★★★ | ★★ | ★★ | 7 |
The scale contains eight items which has three main aspects: selection, comparability and outcome. Assessment result is demonstrated by the number of stars (★) the study obtained. A maximum of nine stars can be given for each study.