What to do if the reader suspects an undisclosed conflict of interest (CoI) in a published article?

• A reader informs the editor of the CoI not disclosed by the author, then:
• Thank the reader and inform them that you plan to investigate
• Contact the author(s) and express your concern. It may be helpful to provide a copy of the journal's policy and its definition of CoI

Two possible situations arise here (1 and 2):

1. The author(s) provide the relevant details, then:

• Thank the author but indicate that this is a serious omission
• Publish, if applicable, a correction to the conflict of interest declaration
• Inform readers of the result

2. The author(s) deny that there is a CoD, so we proceed:

• Clearly explain the journal policy and definition of CoI, and obtain from each author a signed statement on all relevant CoI (if not previously obtained
• Inform readers of the result

Note: To avoid future problems, always obtain a signed CoI statement from all authors and reviewers before publication. Check that the journal's standards include a clear definition of CoI.