Table 2. The Jadad scale for quality assessment of included trials .
| Author/s, year | Q1 | Q2 | Q3 | Q4 | Q5 | Q6 | Q7 | Q8 | Total |
| Pugin et al21 1991 | Y | ND | Y | Y | Y | Y | Y | Y | 7 |
| DeRiso et al22 1996 | Y | Y | Y | Y | N | Y | N | Y | 6 |
| Bergmans et al 23 2001 | Y | ND | Y | Y | Y | Y | N | Y | 6 |
| Fourrier et al 24 2005 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Kollef et al25 2006 | Y | Y | Y | Y | Y | Y | Y | Y | 8 |
| Seguin et al26 2006 | Y | Y | N | N | Y | Y | N | Y | 5 |
| Koeman et al27 2006 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Segers et al 28 2006 | Y | Y | Y | Y | Y | Y | Y | Y | 8 |
| Bellissimo-Rodrigues et al29 2009 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Munro et al 30 2009 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Özçaka et al31 2012 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Haghighi et al32 2016 | Y | ND | N | ND | ND | Y | N | Y | 3 |
| Nasiriani et al33 2016 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Fernanda de Lacerda Vidal et al34 2017 | Y | Y | Y | Y | Y | Y | N | Y | 7 |
| Zand et al35 2017 | Y | Y | N | N | Y | Y | Y | Y | 6 |
| Chacko et al36 2017 | Y | Y | Y | ND | Y | Y | N | Y | 6 |
| Khaky et al37 2018 | Y | ND | Y | ND | Y | Y | N | Y | 5 |
Q1 = Was the research described as randomized?
Q2 = Was the approach of randomization appropriate?
Q3 = Was the research described as blinding?
Q4 = Was the approach of blinding appropriate?
Q5 = Was there a presentation of withdrawals and dropouts?
Q6 = Was there a presentation of the inclusion/exclusion criteria?
Q7 = Was the approach used to assess adverse effects described?
Q8 = Was the approach of statistical analysis described?
Y: Yes, N: No, ND: Not described.