Table 2 Appraisal of reviewed studies using the AXIS tool
| Â | Hedman et al. [33] | Li et al. [34] | Bhatta and Glantz [35] | Alzahrani et al. [37] | Farsalinos et al. [37] | Parekh et al. [38] |
|---|---|---|---|---|---|---|
Were the aims/objectives of the study clear? | Yes | Yes | Yes | Yes | Yes | Yes |
Was the study design appropriate for the stated aim(s)? | Yes | Yes | Yes | Yes | Yes | Yes |
Was the sample size justified? | Yes | Yes | Yes | Yes | Yes | Yes |
Was the target/reference population clearly defined? (Is it clear who the research was about?) | Yes | Yes | Yes | Yes | Yes | Yes |
Was the sample frame taken from an appropriate population base so that it closely represented the target/reference population under investigation? | Don't know | Yes | Yes | Yes | Yes | Yes |
Was the selection process likely to select subjects/participants that were representative of the target/reference population under investigation? | Yes | Yes | Yes | Yes | Yes | Yes |
Were measures undertaken to address and categorize non-responders? | Yes | Don't know | Don't know | Don't know | Don't know | Don't know |
Were the risk factor and outcome variables measured appropriate to the aims of the study? | Yes | Yes | Yes | Yes | Yes | Yes |
Were the risk factor and outcome variables measured correctly using instruments/measurements that have been trialed, piloted, or published previously? | Yes | Yes | Yes | Yes | Yes | Yes |
Is it clear what was used to determine statistical significance and/or precision estimates? (e.g., p values, Cis) | Yes | Yes | Yes | No | Yes | Yes |
Were the methods (including statistical methods) sufficiently described to enable them to be repeated? | Yes | Yes | Yes | Yes | Yes | Yes |
Were the basic data adequately described? | Yes | Yes | Yes | Yes | Yes | Yes |
Does the response rate raise concerns about non-response bias?* | Yes | Don't know | Don't know | Don't know | Don't know | Don't know |
If appropriate, was information about non-responders described? | Yes | Don't know | Don't know | Don't know | Don't know | Don't know |
Were the results internally consistent? | Yes | Yes | Yes | Yes | Yes | Yes |
Were the results for the analyses described in the methods presented? | Yes | Yes | Yes | Yes | Yes | Yes |
Were the authors discussions and conclusions justified by the results? | Yes | Yes | Yes | Yes | Yes | Yes |
Were the limitations of the study discussed? | Yes | Yes | Yes | Yes | Yes | Yes |
Were there any funding sources or conflicts of interest that may affect the authors' interpretation of the results?* | Don't know | Don't know | Don't know | Don't know | Don't know | No |
Was ethnical approval or consent of participants attained? | Yes | Yes | Yes | Yes | Yes | Yes |
Overall | 17 | 16 | 16 | 15 | 16 | 17 |