“…Six of the 17 included studies demonstrate at least 80% power for detecting a meaningful statistical significant change in their primary outcome measure25,29,31,32–34,36,38 and four studies failed to include sufficient patient numbers as determined by their sample size calculations 20,21,27,35. Seven studies did not mention whether their study was sufficiently powered,22–24,26,28,30,37,39 but three of these studies include less than 40 patients in each study arm26,28,30 and are most likely underpowered.…”