Blinding and exclusions after allocation in randomised controlled trials : survey of published parallel group trials in obstetrics and gynaecology.
To assess the methodological quality of approaches to blinding and to handling of exclusions as reported in randomised trials from one medical specialty.
Design-Survey of published, parallel group randomised controlled trials.
Data sources-A random sample of 110 reports in which allocation was described as randomised from the 1990 and 1991 volumes of four journals of obstetrics and gynaecology.
Main outcome measures-The adequacy of the descriptions of double blinding and exclusions after randomisation.
Though 31 trials reported being double blind, about twice as many could have been.
Of the 31 trials only eight (26%) provided information on the protection of the allocation schedule and only five (16%) provided some written assurance of successful implemention of double blinding.
Of 38 trials in which the authors provided sufficient information for readers to infer that no exclusions after randomisation had occurred, six (16%) reported adequate allocation concealment and none stated that an intention to treat analysis had been performed.
That compared with 14 (27%) and six (12%), respectively, for the 52 trials that reported exclusions.
Conclusions-Investigators could have double blinded more often.
When they did double blind, they reported poorly and rarely evaluated it.
Paradoxically, trials that reported exclusions seemed generally of a higher methodological standard than those that had no apparent exclusions.
Exclusions from analysis m...
Mots-clés Pascal : Essai thérapeutique contrôlé, Gynécologie, Obstétrique, Aveugle, Arrêt traitement, Protocole thérapeutique, Randomisation, Homme, Etats Unis, Synthèse bibliographique, Amérique du Nord, Amérique
Mots-clés Pascal anglais : Controlled therapeutic trial, Gynecology, Obstetrics, Blind, Withdrawal, Therapeutic protocol, Randomization, Human, United States, Bibliographic survey, North America, America
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 96-0195773
Code Inist : 002B30A01C. Création : 199608.