OBJECTIVE: To compare the reporting on blinding in protocols and articles describing randomized controlled trials. STUDY DESIGN AND SETTING: We studied 73 protocols of trials approved by the scientific/ethical committees for Copenhagen and Frederiksberg, 1994 and 1995, and their corresponding publications. RESULTS: Three out of 73 trials (4%) reported blinding in the protocol that contradicted that in the publication (e.g., "open" vs. "double blind"). The proportion of "double-blind" trials with a clear description of the blinding of participants increased from 11 out of 58 (19%) when based on publications alone to 39 (67%) when adding the information in the protocol. The similar proportions for the blinding of health care providers were 2 (3%) and 22 (38%); and for the blinding of data collectors, they were 8 (14%) and 14 (24%). In 52 of 58 publications (90%), it was unclear whether all patients, health care providers, and data collectors had been blinded. In 4 of the 52 trials (7%), the protocols clarified that all three key trial persons had been blinded. CONCLUSIONS: The reporting on blinding in both trial protocols and publications is often inadequate. We suggest developing international guidelines for the reporting of trial protocols and public access to protocols.
OBJECTIVE: To compare the reporting on blinding in protocols and articles describing randomized controlled trials. STUDY DESIGN AND SETTING: We studied 73 protocols of trials approved by the scientific/ethical committees for Copenhagen and Frederiksberg, 1994 and 1995, and their corresponding publications. RESULTS: Three out of 73 trials (4%) reported blinding in the protocol that contradicted that in the publication (e.g., "open" vs. "double blind"). The proportion of "double-blind" trials with a clear description of the blinding of participants increased from 11 out of 58 (19%) when based on publications alone to 39 (67%) when adding the information in the protocol. The similar proportions for the blinding of health care providers were 2 (3%) and 22 (38%); and for the blinding of data collectors, they were 8 (14%) and 14 (24%). In 52 of 58 publications (90%), it was unclear whether all patients, health care providers, and data collectors had been blinded. In 4 of the 52 trials (7%), the protocols clarified that all three key trial persons had been blinded. CONCLUSIONS: The reporting on blinding in both trial protocols and publications is often inadequate. We suggest developing international guidelines for the reporting of trial protocols and public access to protocols.
Authors: An-Wen Chan; Jennifer M Tetzlaff; Peter C Gøtzsche; Douglas G Altman; Howard Mann; Jesse A Berlin; Kay Dickersin; Asbjørn Hróbjartsson; Kenneth F Schulz; Wendy R Parulekar; Karmela Krleza-Jeric; Andreas Laupacis; David Moher Journal: BMJ Date: 2013-01-08
Authors: Kerry Dwan; Douglas G Altman; Lynne Cresswell; Michaela Blundell; Carrol L Gamble; Paula R Williamson Journal: Cochrane Database Syst Rev Date: 2011-01-19
Authors: An-Wen Chan; Jennifer M Tetzlaff; Douglas G Altman; Andreas Laupacis; Peter C Gøtzsche; Karmela Krle A-Jerić; Asbjørn Hrobjartsson; Howard Mann; Kay Dickersin; Jesse A Berlin; Caroline J Dore; Wendy R Parulekar; William S M Summerskill; Trish Groves; Kenneth F Schulz; Harold C Sox; Frank W Rockhold; Drummond Rennie; David Moher Journal: Rev Panam Salud Publica Date: 2015-12
Authors: An-Wen Chan; Jennifer M Tetzlaff; Douglas G Altman; Andreas Laupacis; Peter C Gøtzsche; Karmela Krleža-Jerić; Asbjørn Hróbjartsson; Howard Mann; Kay Dickersin; Jesse A Berlin; Caroline J Doré; Wendy R Parulekar; William S M Summerskill; Trish Groves; Kenneth F Schulz; Harold C Sox; Frank W Rockhold; Drummond Rennie; David Moher Journal: Ann Intern Med Date: 2013-02-05 Impact factor: 25.391
Authors: Meredith M Whiteside; Ellen S Shorter; Mathew S Margolis; Fatima Alvi; Julia B Huecker; Tammy P Than; Mary K Migneco; Jennifer S Harthan; Christina E Morettin; Andrew T E Hartwick; Spencer D Johnson; Chamila D Perera; Mae O Gordon Journal: Optom Vis Sci Date: 2021-05-01 Impact factor: 1.973