The relationship between study findings and publication outcome in anesthesia research: a retrospective observational study examining publication bias

Purpose Many areas of medicine have shown bias towards the publication of studies with positive results. To estimate publication bias in the anesthesia literature, we reviewed all abstracts presented at the American Society of Anesthesiologists (ASA) annual meetings over a four-year period and compared study results (positive vs negative) with publication outcomes. Methods This review included all abstracts from the 2001-2004 ASA annual meetings performed as randomized-controlled trials in humans. We scored their outcome results as positive or negative and assessed abstract quality using a 13-point scoring system. We then performed a systematic literature search to identify any subsequent publication of the studies and calculated the relative risk (RR) for journal publication by comparing positive vs negative studies. Results Of 5,918 abstracts reviewed, 1,052 met inclusion criteria, and 564 (53.6%) of the abstracts proceeded to publication. The RR for abstracts with positive results proceeding to journal publication was 1.42 (95% confidence interval, 1.22 to 1.66; P < 0.001). This result did not change significantly after adjusting for study size and abstract quality score during logistic regression modelling. There was no significant difference in the abstract quality score between positive vs negative studies or between abstracts proceeding vs not proceeding to publication. Conclusions Approximately half of the ASA annual meeting abstracts proceed to publication. After adjustment for study quality and size, abstracts with positive results were more likely to proceed to journal publication than those with negative results, suggesting publication bias in the anesthesia literature.