Table 5. Methodological quality of included studies based on Downs and Black** checklist (n = 35).
| Study | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | Quality Score | Percentage (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Karu et al., (1995) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/24 | 46 |
| Graupe et al, (2000) | 1 | 1 | 0 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 0* | 0* | 1 | 0* | N/A | N/A | 0 | 0 | 0* | N/A | 8/21 | 38 |
| Griffin et al., (2002) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/24 | 46 |
| Godfrey et al., (2002) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Eser et al., (2003) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/22 | 55 |
| Thomas et al., (2003) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/24 | 46 |
| Kebaetse et al., (2005) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Decker et al., (2010) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/22 | 55 |
| del-Ama et al., (2012) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/24 | 50 |
| Chang and Shields, (2011) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 10/24 | 42 |
| Graham et al., (2006) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/24 | 50 |
| Thrasher et al., (2005) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/22 | 55 |
| Bickel et al., (2004) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 10/24 | 42 |
| Scott et al., (2007) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Scott et al., (2005) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Deley et al., (2015) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/22 | 55 |
| Gorgey et al., (2014) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 1 | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 1 | 1 | 1 | N/A | 1 | 0 | 0 | 1 | N/A | 16/23 | 70 |
| Chou et al., (2008) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Popovic and Malesevic, (2009) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 0* | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 9/22 | 41 |
| Malešević et al., (2010) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 10/22 | 45 |
| Nguyen et al., (2011) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 12/22 | 55 |
| Sayenko et al., (2014) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/22 | 50 |
| Downey et al., (2014) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | N/A | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 13/24 | 54 |
| Shields and Dudley-Javoroski (2006) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 1 | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 11/23 | 48 |
| Shields et al., (2006) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 1 | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 1 | 1 | 0* | N/A | 0 | 0 | 0 | 1 | N/A | 14/23 | 61 |
| Butler et al., (2004) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0 | 1 | 0* | N/A | 1 | 0 | 0 | 0 | N/A | 12/23 | 52 |
| Gerrits et al., (2000) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 1 | 0* | 0* | 0 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 10/23 | 43 |
| Gerrits et al., (2002) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 0 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0* | N/A | 10/23 | 43 |
| Fornusek and Davis, (2004) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 0 | N/A | 11/23 | 48 |
| Hartkopp et al., (2003) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 1 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | 1 | 0 | 0 | 1 | N/A | 13/23 | 57 |
| Peckham et al., (1976) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0* | 1 | 0* | N/A | N/A | 0 | 0 | 0 | N/A | 10/22 | 45 |
| Sabatier et al., (2006) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 1 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 1 | 1 | 0* | N/A | 0 | 0 | 0 | 0* | N/A | 12/23 | 52 |
| Gorgey et al., (2015) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 0 | 0 | 0 | 1 | N/A | 1 | 1 | 1 | 0* | N/A | N/A | 0 | 0 | 0* | N/A | 10/22 | 45 |
| Shields et al., (2006) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0 | 1 | 0* | N/A | 1 | 0 | 0 | 0 | N/A | 11/23 | 48 |
| Dudley-Javoroski et al., (2011) | 1 | 1 | 1 | 1 | N/A | 1 | 1 | 0 | 0 | 0 | 0* | 0* | 1 | 0 | 0 | 1 | N/A | 1 | 0 | 1 | 0* | N/A | 1 | 0 | 0 | 0 | N/A | 11/23 | 48 |
Abbreviation: D&B criteria met = 1, D&B criteria not met = 0, Unable to determine = *0, i.e. scored 0, Criteria is not applicable to the study = N/A, Unable to determine = UTD.
The table presents the grading of included studies based on the D&B criteria 1 to 27.
Downs and Black**- Criteria are as summarised below
1-Hypothesis/aim stated, 2- Outcome described in introduction/ method, 3- Participants’ characteristics described, 4- Intervention described, 5- Distribution of principal confounders described, 6- Findings described, 7- Data distribution, 8- Description of adverse events, 9- Characteristics of participants’ lost to follow-up described, 10- Exact p-value reported, 11- Participants’ sources described, 12- Participants’ selection described, 13- Appropriateness of the experimental facility, 14- Blinding of the participants to the intervention, 15- Blinding of the examiner, 16- “Data dredging”, 17- Analysis adjustment to different length of follow-up, 18- Appropriate statistics used to measure outcomes, 19- Adherence to the intervention, 20- Accuracy of outcome measures, 21- Source of participant for comparison groups, 22- Time period of participants’ recruitment, 23- Participants’ randomisation, 24- Randomised intervention assignment, 25- Adjustment for confounders during analysis, 26- Consideration to loss to follow-up, 27- Statistical power of the outcome of the study.
Criterion 5 has a maximum of 2 points while others have a maximum of 1 point each. Points were awarded only when the criteria were clearly described.