Endorsement and implementation of high impact factor medical journals on the International Committee of Medical Journal Editors (ICMJE) policy of mandatory clinical trial registration

Objective: We determined the proportion of highest impact factor journals that follows the ICMJE policy of clinical trial registration and identified factors associated with policy implementation. Study design and setting: Ten highest impact factor journals from ten specialties were identified from the 2009 Journal Citation Reports. Instructions for authors were reviewed for the statements regarding the trial registration. If the registration policy was mentioned in the instructions, the published articles were assessed to determine if the policy was actually implemented. The publishers, membership in Committee on Publication Ethics, journal vintage, etc., were analyzed for association with the policy implementation. Results: Of 87 relevant journals, 58.6% endorsed the policy and 35.6% strictly implemented it. Factors for journals associated with strict clinical trial registration policy implementation were Internal Medicine specialty (OR 19.19; 95%CI: 2.21, 166.50; p = 0.007), ICMJE's URM followers (OR 7.14; 95%CI: 2.62, 19.46; p < 0.001), longer years of publication (OR for every 10 year 1.31; 95%Cl: 1.16, 1.49; p = 0.001), and higher impact factors (OR for every 1 JIF 1.70; 95%CI: 1.25, 2.32;p = 0.001). Conclusion: Only one third of the highest impact factor journals strictly implemented ICMJE policy. Associated factors were identified.