The influence of study characteristics on reporting of subgroup analyses in randomised controlled trials: systematic review.

Sun X, Briel M, Busse JW, You JJ, Akl EA, Mejza F, Bala MM, Bassler D, Mertz D, Diaz-Granados N, Vandvik PO, Malaga G, Srinathan SK, Dahm P, Johnston BC, Alonso-Coello P, Hassouneh B, Troung J, Dattani ND, Walter SD, Heels-Ansdell D, Bhatnagar N, Altman D, Guyatt GH. The influence of study characteristics on reporting of subgroup analyses in randomised controlled trials: systematic review. BMJ 2011; 342; d1569 . Vitenskapelig artikkel 2011.BMJ 2011; 342; d1569