Discordance between conclusions stated in the abstract and conclusions in the article: analysis of published randomized controlled trials of systemic therapy in lung cancer.

Purpose: Clinicians may read only the abstract of an article to keep abreast of newly published randomized controlled trials (RCTs). However, discordances have been noticed in summary conclusions in the abstracts and the main body of some articles. This article evaluated such discordances in detail.

Methods: RCTs of systemic therapy for lung cancer published between 2004 and 2009 were considered. Conclusions in the body of the articles and those in the abstracts were graded by using a 7-point Likert scale; 1 for strong endorsement of the control arm, 4 for a neutral statement, and 7 for strong endorsement of the experimental arm. Conclusions were classified as discordant if the difference in scores was ≥ 2. χ(2) tests and logistic regression were used to identify factors associated with discordance.

Results: From among 114 eligible RCTs identified (90 for non-small-cell and 24 for small-cell lung cancer), 11 (10%) articles presented discordant conclusions in the abstract and in the body of the articles. Discordance was most common when the experimental arm was strongly supported in the abstract but not in the body of the article (nine of 11; 82%); however, the converse was much less common (two of 11; 18%; P < .001). Intraclass correlations for the two reviewers were ≥ 0.9. The discordances were found to be independent of trial-related factors.

Conclusion: Conclusive statements in the abstract can differ from those in the full text. Clinicians should use caution when they consider making changes in their practice on the basis of reading only the abstract of a published RCT.