Article type
Year
Abstract
Introduction: While investigations have detailed the poor quality of the reporting of randomisation in recently published randomised controlled trials (RCTs), a paucity of information exists concerning the other methodological components. To address that deficiency, we assessed the level of reporting on double-blinding and handling of exclusions in four journals of obstetrics and gynaecology. We also examined the data for suggestions that some reports of trials that provided an impression of not having had exclusions may have actually had exclusions.
Objective: To assess the methodological quality of approaches to blinding and to the handling of exclusions, as reported in randomised trials from one medical specialty.
Methods: We conducted a survey of published, parallel group RCTs. We selected 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.
Results: Of the 31 trials reported to have been double-blind, 45% provided minimally sufficient descriptions of double-blinding, 26% provided information on the protection of allocation schedule, and 16% provided some written assurance of successfully implementing double-blinding. In the 49 trials in which the authors provided sufficient information for readers to infer that no exclusions after randomisation had occurred, 22% explicitly stated that no exclusions had occurred, and only one (2%) stated that an intent-to-treat analysis had been performed. On average, these 49 trials provided methodological information of inferior quality to that provided from the 52 trials that explicitly reported exclusions.
Discussion: These papers displayed a poor standard of reporting of double-blinding methods. Also, exclusions from the analysis may have been made in some of the trials in which no exclusions were reported. Paradoxically, trials that reported exclusions generally seemed of a higher methodological standard than those not reporting exclusions. Editors and readers of randomised trial reports need to be aware that reporting of exclusions may be flawed in a way that frequently provides a misleading impression of trial quality.
Objective: To assess the methodological quality of approaches to blinding and to the handling of exclusions, as reported in randomised trials from one medical specialty.
Methods: We conducted a survey of published, parallel group RCTs. We selected 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.
Results: Of the 31 trials reported to have been double-blind, 45% provided minimally sufficient descriptions of double-blinding, 26% provided information on the protection of allocation schedule, and 16% provided some written assurance of successfully implementing double-blinding. In the 49 trials in which the authors provided sufficient information for readers to infer that no exclusions after randomisation had occurred, 22% explicitly stated that no exclusions had occurred, and only one (2%) stated that an intent-to-treat analysis had been performed. On average, these 49 trials provided methodological information of inferior quality to that provided from the 52 trials that explicitly reported exclusions.
Discussion: These papers displayed a poor standard of reporting of double-blinding methods. Also, exclusions from the analysis may have been made in some of the trials in which no exclusions were reported. Paradoxically, trials that reported exclusions generally seemed of a higher methodological standard than those not reporting exclusions. Editors and readers of randomised trial reports need to be aware that reporting of exclusions may be flawed in a way that frequently provides a misleading impression of trial quality.