... Most of the trials included in the meta-analysis were conducted in the United Kingdom (16 out of 36, 44%), [23][24][25][26][27]34,[38][39][40][41]43,44,50,51,56,57 followed by Canada (7 out of 36, 19%), 34,44,45,47,48,52,55 the Czech Republic (5 out of 36, 14%), 27,34,37,39,44 the United States (4 out of 36, 11%), 22,28,30,36 the Netherlands (3 out of 36, 8%), 29,33,49 Austria (2 out of 36, 6%), 37,54 Belgium (2 out of 36, 6%), 30,44 Spain (2 out of 36, 6%), 34,39 Switzerland (2 out of 36, 6%), 31,53 Italy (2 out of 36, 6%), 35,39 and Germany (2 out of 36, 6%), 32,42 with the remaining countries (Denmark, 46 France, 34 Poland, 39 and Romania) 44 contributing participants to 1 study each. Of the included studies, 6 trials recruited patients from more than 1 country (range: 2-5 countries). ...