Problems with the use of composite endpoints in cardiovascular trials: systematic review of randomised controlled trials - Ferreira-Gonzles, I; Permanyer-Miralda, G; Domingo-Salvany, A; Busse, JW; Heels-Ansdell, D; Montori, VM; Akl, EA; Bryant, DM; Alonso-Coello, P; Alonso, J; Worster, A; Upadhye, S; Jaeschke, R; Schnemann, HJ; Pacheco-Huergo, V; Wu, P; Mills, EJ; Guyatt, GH (Brit Med J, 2007)