Citation bias in imaging research: are studies with higher diagnostic accuracy estimates cited more often?

Objectives: To assess the risk of citation bias in imaging diagnostic accuracy research by evaluating whether studies with higher accuracy estimates are cited more frequently than those with lower accuracy estimates. Methods: We searched Medline for diagnostic accuracy meta-analyses published in imaging journals from January 2005 to April 2016. Primary studies from the meta-analyses were screened; those assessing the diagnostic accuracy of an imaging test and reporting sensitivity and specificity were eligible for inclusion. Studies not indexed in Web of Science, duplicates, and inaccessible articles were excluded. Topic (modality/subspecialty), study design, sample size, journal impact factor, publication date, times cited, sensitivity, and specificity were extracted for each study. Negative binomial regression was performed to evaluate the association of citation rate (times cited per month since publication) with Youden’s index (sensitivity + specificity -1), highest sensitivity, and highest specificity, controlling for the potential confounding effects of modality, subspecialty, impact factor, study design, sample size, and source meta-analysis. Results: There were 1016 primary studies included. A positive association between Youden’s index and citation rate was present, with a regression coefficient of 0.33 (p = 0.016). The regression coefficient for sensitivity was 0.41 (p = 0.034), and for specificity, 0.32 (p = 0.15). Conclusion: A positive association exists between diagnostic accuracy estimates and citation rates, indicating that there is evidence of citation bias in imaging diagnostic accuracy literature. Overestimation of imaging test accuracy may contribute to patient harm from incorrect interpretation of test results. Key Points: • Studies with higher accuracy estimates may be cited more frequently than those with lower accuracy estimates. • This citation bias could lead clinicians, reviews, and clinical practice guidelines to overestimate the accuracy of imaging tests, contributing to patient harm from incorrect interpretation of test results.