In the case of studies including multiple intervention
groups, we will follow the recommended method suggested
by the Cochrane Collaboration section 16.5 [53] for
combining multiple groups from one study. For continuous
outcomes, means and standard deviations will be
combined using methods and formulae described in
chapter 7 (7.7.3.8) - combining groups, in the Cochrane
Handbook of Systematic Reviews of Interventions.
The following will be considered in relation to assessing
the risk of bias in multiple intervention studies: