Report and Interpretation of Randomized Controlled Trials with Statistically Nonsignificant Results for Primary Outcomes in the Anesthesia Domain: A Systematic Review

Although the Declaration of Helsinki emphasizes the importance of accurate and transparent research communication, authors’ discretion in interpreting outcomes may spin their results and force a favorable outlook. This study investigated the use of “spin” in reporting randomized controlled trials (RCTs) in the anesthesia domain.

We searched the PubMed database for articles reporting RCTs in the anesthesia domain published over 5 years (2014–2018). We excluded articles on cost-effectiveness, diagnostic test accuracy, and non-English language reports. The spin characteristics with reference to the location, extent, and strategy were assessed. We screened 799 articles and included 211 eligible articles. Spin reporting was found in 86 articles (40.8%), and was identified in the Results section in 75 articles, the results synthesis in the Discussion section in 52 articles, and the Conclusion section in 66 articles. The most common spin location was the Results section, and the type of spin was focused on statistically significant within-group comparisons. The most common spin strategy was language use that implied a benefit.

Spin reporting was highly prevalent in RCT reports in the anesthesia domain, and abstracts may effectively reflect the spin reporting status in articles. We scrutinized instances of spin within RCTs that failed to yield statistically significant results; however, the potential existence of spin in studies reporting statistically significant results may also exist. This warrants critical evaluation and consideration, and the application of a fragility index may be indispensable for this purpose.