Data synthesis
We will carry out statistical analysis using the Review Managersoftware (RevMan 2014). We will use fixed-effect meta-analysisfor combining data where it is reasonabl e to assume that studies areestimating the same underlying treatment effect: i.e. where trialsare e xamining the same intervention, and the trials’ populationsand methods are judged sufficiently similar. If there is clinical het-erogeneity sufficient to expect that the underlying treatment ef-fects differ between trials, or if substantial statistical heterogeneityis de tected, we will use random-effects meta-analysis to producean overall summary, if an average treatment effect across tr ials isconsidered clinically meaningful. The r andom-effects summarywill be treated as the average range of possible treatment effectsand we will discuss the clinical implications of treatment effectsdiffering between trials. If the average treatment effect is not clin-ically meaningful, we will not combine trials.If we use random-effects analyses, the results will be presented asthe average treatment effect with 95% confidence intervals, andthe estimates of T² and I²