Dependability of results in conference abstracts of randomized controlled trials in ophthalmology and author financial conflicts of interest as a factor associated with full publication

Abstract

Background: Discrepancies between information in conference abstracts and full publications describing the same randomized controlled trial have been reported. The association between author conflicts of interest and the publication of randomized controlled trials is unclear. The objective of this study was to use randomized controlled trials in ophthalmology to evaluate (1) the agreement in the reported main outcome results by comparing abstracts and corresponding publications and (2) the association between the author conflicts of interest and publication of the results presented in the abstracts.

Methods: We considered abstracts describing results of randomized controlled trials presented at the 2001-2004 Association for Research in Vision and Ophthalmology conferences as eligible for our study. Through electronic searching and by emailing abstract authors, we identified the earliest publication (journal article) containing results of each abstract's main outcome through November 2013. We categorized the discordance between the main outcome results in the abstract and its paired publication as qualitative (a difference in the direction of the estimated effect) or as quantitative. We used the Association for Research in Vision and Ophthalmology categories for conflicts of interest: financial interest, employee of business with interest, consultant to business with interest, inventor/developer with patent, and receiving ≥ 1 gift from industry in the past year. We calculated the relative risks (RRs) of publication associated with the categories of conflicts of interest for abstracts with results that were statistically significant, not statistically significant, or not reported.

Results: We included 513 abstracts, 230 (44.8 %) of which reached publication. Among the 86 pairs with the same main outcome domain at the same time point, 47 pairs (54.7 %) had discordant results: qualitative discordance in 7 pairs and quantitative discordance in 40 pairs. Quantitative discordance was indicated as < 10, 10-20, > 20 %, and unclear in 14, 5, 14, and 7 pairs, respectively. First authors reporting of one or more conflicts of interest was associated with a greater likelihood of publication (RR = 1.31; 95 % CI = 1.04 to 1.64) and a shorter time-to-publication (log-rank p = 0.026). First author conflicts of interests that were associated with publication were financial support (RR = 1.50; 95 % CI = 1.19 to 1.90) and one or more gifts (RR = 1.42; 95 % CI = 1.05 to 1.92). The association between conflicts of interest and publication remained, irrespective of the statistical significance of the results.

Conclusions: More than half the abstract/publication pairs exhibited some amount of discordance in the main outcome results, calling into question the dependability of conference abstracts. Regardless of the main outcome results, the conflicts of interests of the abstract's first author were associated with publication.

Fig. 1

Kaplan-Meier plots showing time to full publication of abstracts of randomized controlled trials (RCTs) presented at the ARVO conference during the years 2001–2004, overall and by various study characteristics, author characteristics, and statistical significance of results for the main outcome. a All abstracts. b By study funding. Blue = funded; green = not reported; maroon = not funded. c By number of centers. Blue = multicenter; green = not reported; maroon = single center. d By reporting of statistical significance of results for the main outcome. Blue = reported; maroon = not reported. e By statistical significance of results for the main outcome. Maroon = statistically significant; blue = not statistically significant. f By whether or not the “first author” reported at least one conflict of interest (COI). Maroon = at least one COI; blue = no COI. g By whether or not the “last author” reported at least one COI. Maroon = at least one COI; blue = no COI or not applicable/abstract had only one author. h By whether or not ANY AUTHOR reported at least one COI. Maroon = at least one COI; blue = no COI

Fig. 2

The amount of agreement in the main outcome results in 86 pairs of conference abstracts and full publications. Exact agreement (green), qualitative discordance (yellow), and various categories of quantitative discordance (blue) are depicted under two different definitions of agreement – exact agreement (a, left) and exact agreement or < 10 % discordance (b, right)