Data synthesis
We will carry out statistical analysis using the Review Manager
software (RevMan 2014). We will use fixed-effect meta-analysis
for combining datawhere it is reasonable to assume that studies are
estimating the same underlying treatment effect: i.e. where trials
are examining the same intervention, and the trials’ populations
and methods are judged sufficiently similar. If there is clinical heterogeneity
sufficient to expect that the underlying treatment effects
differ between trials, or if substantial statistical heterogeneity
is detected, we will use random-effects meta-analysis to produce
an overall summary, if an average treatment effect across trials is
considered clinically meaningful. The random-effects summary
will be treated as the average range of possible treatment effects
and we will discuss the clinical implications of treatment effects
differing between trials. If the average treatment effect is not clinically
meaningful, we will not combine trials.
If we use random-effects analyses, the results will be presented as
the average treatment effect with 95% confidence intervals, and
the estimates of T² and I².