Author / Adequate sequence generation / Allocation concealment / Blinding / Addressed incomplete outcome data / Free of selective reporting / Free of other bias
Mountain64 / no / unclear / no / yes / unclear / unclear
Longland28 / yes / unclear / yes / yes / unclear / unclear
Madsen43 / unclear / unclear / yes / yes / unclear / no
Andersen, Bendtsen65 / unclear / unclear / yes / yes / unclear / unclear
Andersen, Korner66 / no / unclear / unclear / unclear / unclear / unclear
Mackie29 / unclear / unclear / unclear / yes / unclear / unclear
Bates67 / yes / yes / yes / yes / unclear / unclear
Gilmore and Martin30 / unclear / unclear / unclear / no / unclear / unclear
Gilmore and Sanderson68 / unclear / unclear / unclear / yes / unclear / unclear
Jensen31 / unclear / unclear / yes / yes / unclear / unclear
McCluskey69 / unclear / unclear / yes / yes / unclear / unclear
Galland36 / unclear / unclear / yes / unclear / unclear / no
Stokes35 / unclear / unclear / unclear / unclear / unclear / no
Barr40 / unclear / yes / yes / yes / unclear / no
Tanphiphat37 / unclear / unclear / yes / yes / unclear / unclear
Andersen,Burcharth41 / unclear / unclear / unclear / yes / unclear / unclear
Foster34 / unclear / unclear / no / yes / unclear / unclear
Gray70 / unclear / unclear / yes / unclear / unclear / no
Kothuis71 / unclear / unclear / yes / yes / unclear / unclear
Ostergaard72 / no / unclear / unclear / unclear / unclear / no
Walsh73 / unclear / unclear / yes / yes / unclear / unclear
de Jong74 / unclear / unclear / yes / yes / unclear / unclear
Galland75 / no / no / unclear / unclear / unclear / unclear
Sherlock33 / yes / unclear / unclear / unclear / unclear / unclear
Sood32 / unclear / unclear / unclear / yes / unclear / unclear
Juul76 / no / unclear / unclear / yes / unclear / no
Lau77 / unclear / unclear / unclear / yes / unclear / no
Moesgaard and Nielsen42 / unclear / unclear / unclear / unclear / unclear / no
Moesgaard. Nielsen and Hjortrup78 / unclear / unclear / unclear / yes / unclear / unclear
Raahave46 / unclear / unclear / yes / yes / unclear / unclear
Seco79 / no / unclear / no / unclear / unclear / no
Cervantes-Sanchez55 / unclear / unclear / unclear / unclear / unclear / unclear
Al-Ramahi53 / unclear / unclear / unclear / unclear / unclear / unclear
Pradhan39 / unclear / unclear / unclear / yes / unclear / unclear
Güngördük54 / no / unclear / unclear / unclear / unclear / unclear
Logan80 / unclear / unclear / unclear / yes / unclear / unclear
Ciccone44 / unclear / unclear / yes / unclear / unclear / unclear
Galle45 / unclear / unclear / unclear / unclear / unclear / unclear
Lord38 / yes / yes / yes / yes / unclear / unclear
Rogers81 / unclear / unclear / unclear / unclear / unclear / no
Mathelier82 / yes / unclear / yes / yes / unclear / unclear
Supplement 2: Funnel plots of study groups A and B