Table 1. Methodological details potentially related to bias.

Authors	Year	Phase	Blindness	Withdrawn description	Alpha error	Beta error	ITT analysis	Multicenter	Sponsor
Johnson et al	2004	II	No	Yes	Yes	Yes	Yes	Yes	Industry
Sandler et al	2006	III	No	Yes	Yes	Yes	No	Yes	Industry
Herbst et al	2007	II	Unclear	Yes	No	No	Yes	Yes	Industry
Reck et al	2009	III	Yes	Yes	Yes	Yes	Yes	Yes	Industry
Nishio et al	2009	II	No	Yes	No	No	No	Yes	No report

ITT: intention-to-treat analysis.