Study	Reason for exclusion
Abzug 2011	Descriptive study
Adams 1990	Observational study
Alnot 1998	Descriptive study
Amadio 1990	Descriptive study
Angly 2006	Observational study
Ardouin 2011	Observational study
Atroshi 1997	Observational study
Atroshi 1998	Descriptive study
Bamberger 1992	Observational study
Barron 1998	Observational study
Battiston 1997	Descriptive study
Belcher 2001	Trial terminated early due to adverse effects and only 6 month outcome data
Beldame 2010	Observational study
Bellemère 2011a	Observational study
Berggren 2001	No intervention of interest
Bezwada 2002	Observational study
Brand 2007	Observational study
Braun 1982	No intervention of interest
Brunton 2011	Descriptive study
Budoff 2002	Observational study
Burton 1973	Review
Burton 1986	Observational study
Burton 1987	Review
Camus 2000	Descriptive study
Caputo 1993	Observational study
Carneiro 2007	No comparison of interest
Carroll 1987	Observational study
Chakrabarti 1997	Observational study
Chamay 1994	Observational study
Clough 1990	Observational study
Conolly 1989	Observational study
Conolly 1993	Descriptive study
Cox 2010	Review
Creamer 1998	Review
Cristiani 1997	Observational study
Dacatra 2001	No intervention of interest
Damen 1997	Observational study
Damen 2000	Observational study
Damen 2001	Observational study
Day 2004	No intervention of interest
Dell 1978	Observational study
Dhar 1994	Observational study
Dodaro 1999	Observational study
Eaton 1979	Observational study
Eaton 1984	Observational study
Eaton 1985	Observational study
Edmunds 1994	No intervention of interest
Egloff 2002	Observational study
Eiken 1970	Observational study
Esenwein 2011	No comparison of interest
Ferlic 1983	Observational study
Forseth 2003	No intervention of interest
Froimson 1987	Review
Fujiwara 2003	Observational study
Fulton 2001	Observational study
Furia 2010	No comparison of interest
Galli 2002	Observational study
Gallinet 2011	Observational study
Gangopadhyay 2008	Review
García‐Mas 2009	Observational study
Gibbons 1999	Observational study
Goldberg 1994	Observational study
Gray 2007	Observational study
Haase 2011	Review
Hannula 1999	Observational study
Harrison 1977	Observational study
Hartigan 2001	Observational study
Hass 1989	Observational study
Hernández‐Cortes 2012	Observational study
Herren 1997	Descriptive study
Hilty 1996	Observational study
Hobby 1998	Observational study
Hofammann 1987	Observational study
Hohendorff 2008	No comparison of interest
Hollevoet 1996	Descriptive study
Holmberg 1996	Observational study
Horlock 2002	No intervention of interest
Isselin 2001	Observational study
Johnston 2012	Observational study
Jörheim 2009	Observational study
Kaarela 1999	Observational study
Kapandji 2002	No intervention of interest
Karlsson 1990	Observational study
Kaszap 2012	Observational study
Kenniston 2008	Review
Kleinman 1991	Observational study
Kocheva 2011	Observational study
Kokkalis 2009	Observational study
Kuhns 2003	Observational study
Kuschner 1996	Review
Köhler 1987	Descriptive study
Lane 1987	Observational study
Lane 2001	Observational study
Lanzetta 1995	Observational study
Le Viet 1996	Observational study
Lehmann 1998	Descriptive study
Li 2011	Review
Lins 1996	Observational study
Linscheid 2000	Review
Lisanti 1997	Observational study
Liu 1999	Observational study
Lovell 1999	Observational study
MacDermid 2003	Observational study
Mandl 2006	No intervention of interest
Marmor 1969	Review
Marmor 1972	Review
Marti 2006	Observational study
Martinez de Aragon 2009	Observational study
Masmejean 2003	Observational study
McGovern 2001	Observational study
Menon 1995	Observational study
Mentzel 2001	Descriptive study
Messina 2000	No intervention of interest
Messina 2002	No intervention of interest
Mo 2004	Observational study
Molitor 1991	Observational study
Muermans 1998	Descriptive study
Mureau 2001	Descriptive study
Nakajima 1996	Observational study
Nilsson 2002	No intervention of interest
Nordback 2012	Observational study
Nusem 2003	Review
Nylén 1993	Observational study
O'Leary 1997	Observational study
O'Leary 2002	Observational study
Oka 2000	Observational study
Panciera 1997	Observational study
Pellegrini 1986	Observational study
Pellegrini 1996	No outcome of interest
Phaltankar 2003	Observational study
Punzi 2012	Review
Pérez‐Úbeda 2003	Observational study
Rab 2006	Observational study
Raven 2007	Observational study
Rayan 1997	Observational study
Ritchie 2008	No comparison of interest
Roberts 2001	Observational study
Robinson 1991	Observational study
Saehle 2002	Observational study
Sakellarides 1989	Observational study
Sammer 2010	Observational study
Sandvall 2010	Observational study
Schmidt 1993	Observational study
Schröder 2002	Descriptive study
Schuhl 2001	Observational study
Smith 2002	Observational study
Smíd 2001	Descriptive study
Sotereanos 1993	Observational study
Stein 2011	Observational study
Stussi 2000	Descriptive study
Swanson 1983	Review
Søndergaard 1991	Observational study
Taghinia 2008	No comparison of interest
Takwale 2002	Observational study
Thomsen 2000	Observational study
Tomaino 1995	Observational study
Tomaino 2000	Observational study
Ulrich‐Vinther 2008	Observational study
van Cappelle 1999	Observational study
van Cappelle 2001	Observational study
Van Giffen 2002	Observational study
Vandenbroucke 1997	Observational study
Vermeulen 2011	Review
Voulliaume 2003	Observational study
Wachtl 1997	Descriptive study
Wachtl 1998	Observational study
Wajon 2005	Review
Yang 1998	Observational study
Yao 2010	Observational study
Yao 2012	Descriptive study
Young 1998	Observational study
Young 2004	Review
Zancolli 2001	Review
Zollinger 2008	Observational study