Selective citation practices in imaging research: Are diagnostic accuracy studies with positive titles and conclusions cited more often?

OBJECTIVE. The purpose of this study was to examine the existence of selective citation practices in the imaging literature by assessing whether diagnostic accuracy studies with positive titles or conclusions are cited more frequently than those with negative (or neutral) titles or conclusions. MATERIALS AND METHODS. MEDLINE was searched for meta-analyses of diagnostic accuracy studies published in imaging journals from January 2005 to April 2016. Primary studies from the meta-analyses were screened for eligibility. Titles and conclusions were classified independently in duplicate. A negative binomial regression analysis controlling for several confounding variables was performed to obtain regression coefficients; p values were obtained via likelihood ratio testing. RESULTS. A total of 995 primary studies were included. Fifty-one titles (5.1%) and 782 conclusions (78.6%) were positive or positive with qualifiers; 942 titles (94.7%) and 127 conclusions (12.8%) were neutral; and two titles (0.02%) and 86 conclusions (8.6%) were negative. Studies with positive, neutral, and negative titles were cited a mean of 0.66, 0.50, and 0.06 times per month. Studies with positive, neutral, and negative conclusions were cited a mean of 0.54, 0.42, and 0.34 times per month. Regression coefficients were 1.10 (95% CI, –0.08 to 2.20) and 0.91 (95% CI, –0.27 to 2.00) for positive and neutral titles, relative to negative titles. Regression coefficients were 0.19 (95% CI, 0.03–0.35) and 0.08 (95% CI, –0.12 to 0.27) for positive and neutral conclusions, relative to negative conclusions. Title and conclusion positivity demonstrated positive association with citation rate (p = 0.031 for both). CONCLUSION. Studies with positive titles or conclusions are cited more frequently in imaging diagnostic accuracy literature. This difference may contribute to overestimation of the accuracy of a test and, consequently, suboptimal patient outcomes

Publication bias in diagnostic imaging: conference abstracts with positive conclusions are more likely to be published

Objective: To evaluate whether imaging diagnostic test accuracy conference abstracts with positive conclusions or titles are more likely to reach full-text publication than those with negative (or neutral) conclusions or titles. Methods: Diagnostic accuracy research abstracts were included if they were presented at the 2011 or 2012 Radiological Society of North America conference. Full-text publication status at 5 years post conference abstract submission was determined. Conclusion and title positivity of conference abstracts were extracted, as well as potential confounding factors. The associations of conclusion and title positivity with publication status at 5 years post conference abstract submission were assessed using a multivariable logistic regression model. Conditional odds ratios were calculated to express the strength of associations, adjusting for the confounders. Results: In total, 282/400 (71%) of included conference abstracts reached full-text publication. A total of 246 out of 337 (74%) conference abstracts with positive conclusions resulted in full-text publications, compared with 26/48 (54%) with neutral conclusions and 5/15 (33%) with negative conclusions. In multivariable logistic regression, conclusion positivity was significantly associated with full-text publication (odds ratio 3.6; 95% CI 1.9–6.7 for conference abstracts with positive conclusions, compared with those with non-positive conclusions); this did not apply to title positivity (odds ratio 1.2; 95% CI 0.47–3.0). Conclusion: Imaging conference abstracts with positive conclusions were more likely to be published as full-text articles. Title positivity was not associated with publication. This preferential publication pattern may lead to an overrepresentation of positive studies in the literature. An overrepresentation of positive studies may contribute to inflated estimates of test accuracy and has the potential to adversely influence patient care. Key Points: • Imaging diagnostic test accuracy conference abstracts with positive conclusions were more likely to be reported as full-text articles than those with non-positive conclusions. • The majority (75%) of imaging diagnostic test accuracy conference abstracts with positive conclusions were published, compared with only 53% and 33% with neutral and negative conclusions, respectively. • Conclusion positivity remained associated with the full-text publication of conference abstracts when controlling for multiple potential confounding variables