Inconsistent reporting of surrogate outcomes in randomised clinical trials: cohort study.
OBJECTIVE
To assess if authors of randomised clinical trials convey the fact that they have used surrogate outcomes and discussed their validity.


METHODS
Cohort study.


METHODS
Six major general medical journals.


METHODS
Randomised clinical trials published in 2005 and 2006 that used a surrogate as a primary outcome.


RESULTS
Of 626 published randomised clinical trials, 109 (17%) used a surrogate as a primary outcome. Of these trials, 62 (57%, 95% confidence interval 47% to 67%) clearly reported that the primary outcome was a surrogate. Only 38 (35%, 26% to 45%) also discussed the validity of the surrogate.


CONCLUSIONS
Only about one third of authors of randomised clinical trials that used a surrogate as a primary outcome reported adequately on the surrogate. Better reporting is needed.
la Cour
Jeppe Lerche
JL
Copenhagen Trial Unit, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark. Jeppelerche@hotmail.com
Brok
Jesper
J
Gøtzsche
Peter C
PC
D015331:Cohort Studies; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards*; D016896:Treatment Outcome