Table 2 AMSTAR, assessing methodological quality of systematic reviews
Study | Alkhenzian et al. 2011 | Matrix group 2010 | Flodgren et al. 2011 | Brubakk et al. |
|---|---|---|---|---|
AMSTAR question | Yes, No, Can’t answer, Not applicable |  | ||
1. Was an ‘a priori’ design provided? | Yes | Yes | Yes | Yes |
2. Was there duplicate study selection and data extraction? | No | No | Yes | Yes |
3. Was a comprehensive literature search performed? | Yes | Yes | Yes | Yes |
4. Was the status of publication (i.e. grey literature) used in the inclusion criterion? | No | Yes | No | No |
5. Was a list of studies (included and excluded) provided? | Yes, although only for the included | Yes, although only for the included | Yes, both included and excluded studies | Yes, both included and excluded studies |
6. Were the characteristics of the included studies provided? | Yes | Yes | Yes | Yes |
7. Was the scientific quality of the included studies assessed and documented? | Yes | Yes, No | Yes | Yes |
8. Was the scientific quality of the included studies used appropriately in formulating conclusions? | No | Can’t answer | Yes | Yes |
9. Were the methods used to combine the findings of studies appropriate? | Not applicable (N/A) | Yes | Not applicable (N/A) | Not applicable (N/A) |
10. Was the likelihood of publication bias assessed? | No | No | Yes | Yes |
11. Was the conflict of interest stated? | No | No | Yes | Yes |