Data extraction, (selection and coding)
Selection of studies
Two review authors (N Hanada (NH), M Matsuzaki (MM)) will independently assess for inclusion all potential studies identified as a result of the search strategy. We will resolve any disagreement through discussion or, if required, we will consult a third author (E Ota (EO)).
We will create a study flow diagram to map out the number of records identified, included and excluded.
Data extraction and management
We will design a form to extract data. For eligible studies, two review authors will extract the data using the agreed form. We will resolve discrepancies through discussion or, if required, we will consult a third author. We will enter data into Review Manager software (RevMan 2014) and check it for accuracy.
When information regarding any of the above is unclear, e.g., abstracts only, we will attempt to contact authors of the original reports to provide further details.