[Selective reporting of positive outcomes in randomised trials--secondary publication.. A comparison of protocols with published reports].
BACKGROUND
Selective reporting of positive outcomes is associated with bias.


METHODS
We conducted a cohort study of 102 protocols of randomised trials approved by the Scientific Ethics Committees for Copenhagen and Frederiksberg in 1994-1995 and the corresponding 122 reports.


RESULTS
The median proportion of incompletely reported outcomes per trial was 50%. Statistically significant outcomes were more often fully reported, odds ratio 2.4. In 62% of trials, at least one primary outcome was changed.


CONCLUSIONS
Outcomes in randomised trials are often reported selectively.
Hróbjartsson
Asbjørn
A
H:S Rigshopitalet, Det Nordiske Cochrane Center, University Health Network Toronto, Department of Medicine. a.hrobjartsson@cochrane.dk
Chan
An-Wen
AW
Haahr
Mette T
MT
Gøtzsche
Peter C
PC
Altman
Douglas G
DG
D002985:Clinical Protocols / Q000592:standards*; D015331:Cohort Studies; D003718:Denmark; D006801:Humans; D015201:Meta-Analysis as Topic; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D016896:Treatment Outcome