Spin and Distortion in Surgical Trials
Abstract
Research problem: Randomized controlled trials (RCTs) are essential; however, their validity can be threatened through distortion or spin. This study quantifies publication bias and distorted outcome reporting.
Methodology: All surgical RCTs registered on ClinicalTrials.gov from 1997-2017 were identified and a sample was obtained through random and intentional selection. Failure to publish (proportion of studies that remain unpublished), outcome distortion (changing intended outcomes), and spin (distorted presentation) were explored. Comparisons were made for positive versus negative studies and for high-income (HICs) versus low-middle income countries (LMICs).
Results: In total, 13,761 RCTs were registered (median enrollment size = 96, 94% from HICS). From a sample of 5,094 studies, 1,718 of them were published (34%). In total, 62% of published conclusions declared a significant difference (1,058/1,718), of which 41% (436/1,058) had “turned” positive due to spin or distortion.
Conclusion: While a large volume of RCTs have been registered, many remain unpublished. High proportions of spin and distortion raises concerns for validity of the evidence base.