Discrepancies between Conference Abstracts and Published Manuscripts in Plastic Surgery Studies: A Retrospective Review.

Background Inconsistency in results and outcomes between presented abstracts and corresponding published articles can negatively affect clinical education and care. The objective of this study was to describe the frequency of clinically meaningful change in results and outcomes between abstracts presented at the American Association of Plastic Surgeons annual conference and the corresponding published articles, and to determine risk factors associated with discrepancies. Methods All abstracts delivered as oral presentations at the American Association of Plastic Surgeons conference (2006-2016) were reviewed. Results and outcomes were compared with those in corresponding articles. We defined clinically meaningful discrepancy as any change in the directionality of an outcome, or a quantitative change in results exceeding 10%. Results Four hundred eighty-six abstracts were identified. Of these, 63% (N = 305) advanced to publication. Of the published studies, 19% (N = 59) contained a discrepancy. In 85% of these (N = 50), discrepancies could not be explained by random variation. Changes in sample size were associated with heightened risk for a discrepancy (OR 10.38, 95% CI 5.16-20.86, P < 0.001). A decrease in sample size greater than 10% increased the likelihood of a discrepancy by 25-fold (OR 24.92, 95% CI 8.66-71.68, P < 0.001), whereas an increase in sample size greater than 10% increased the likelihood of a discrepancy by eight-fold (OR 8.36, CI 3.69-19.00, P < 0.001). Conclusions Most discrepancies between abstract and published article were not due to random statistical variation. To mitigate the possible impact of unreliable abstracts, we recommend abstracts be marked as preliminary, that authors indicate whether sample size is final at time of presentation, and that changes to previously reported results be indicated in final publications.