Planned methods of analysis
Data on feasibility, efficacy and safety were extracted where possible. The prevalence of the main outcome variables in each study was combined, to yield a pooled prevalence with a 95% CI for all studies. Data were pooled using random-effects models, to generate a more conservative estimate of the prevalence. Heterogeneity among studies was assessed by using Cochran’s Q (reported with a 2-value and p-value) and the I2 statistic, the latter describing the percentage of variation across studies that is due to heterogeneity, rather than chance, and presented with a 95% CI. Publication bias was measured using Egger’s regression. Statistical analyses were carried out using the R statistical software package, version 2.15.2.13 P