Trials reported in abstracts: the need for a mini-CONSORT

Tags: Oral
Hopewell S, Clarke M

Background: There are concerns over the reliability of trial information reported in abstracts and whether trials reported only as abstracts should be included in systematic reviews.

Objective: To assess the need for a better reporting standard (such as a mini-CONSORT) for trials reported in abstracts.

Methods: Randomized trials reported at the American Society of Clinical Oncology conference (1992) were identified. The Cochrane Central Register of Controlled Trials (Issue 4, 2002) and PubMed (December 2002) were searched to identify corresponding full publications. A checklist (based on CONSORT) was used to compare information reported in the conference abstract with that reported in the abstract of its subsequent full publication. Steps were taken to blind the source of each abstract.

Results: Some aspects of trials were well reported in both the conference abstract and full publication abstract (Table 1). 92% of study objectives, 94% of participant eligibility, 100% of trial interventions and 89% of primary outcomes were the same in both. Other areas were more discrepant; 92% of conference abstracts and 97% of full publication abstracts reported number of participants randomized; but these numbers were the same only 42% of the time. Likewise, 69% of conference abstracts and 50% of full publication abstracts reported number of participants analysed; and these numbers were the same only 11% of the time. This is partly because the conference abstracts were often preliminary reports. Lack of information was a major problem in assessing trial quality; no conference abstracts and 3% of full publication abstracts reported method of allocation concealment, 11% of conference abstracts and 8% of full publication abstracts reported intention-to-treat analyses.

Conclusions: Previous research has shown that trials presented as conference abstracts are poorly reported. However, this study suggests that they may contain as much, or more, useful information than the abstract of a full publication. The quality of reporting of trials in abstracts, both in the proceedings of scientific meetings and in journals, needs to be improved, as this may be all someone appraising a trial has access to.