Appropriateness of Case Reports Citations.

Background: We determined types of peer-reviewed articles that cited case reports and whether citations were "appropriate" or "inappropriate."

Methods: The 20 most highly cited case reports published between January 2011 and April 2016 were identified. All articles referencing these 20 case reports were analyzed for appropriateness of the citation. Appropriate citations referred to the original article specifically as a case report or cited the case report in support of general knowledge. Inappropriate citations used case reports to infer causation, support proof of mechanism, or were deemed irrelevant to claims being supported. Two authors independently coded all citations.

Results: These 20 case reports were cited in 479 articles (median: 24 citations per case report). In most articles (83.6%, = 367), case reports were cited appropriately; in 53.4% ( = 196) of articles, a case report was specifically referred to, and in 46.6% ( = 171) of articles, the case report was used to support general knowledge. For inappropriate citations, in 63.3% ( = 50) of articles, case reports were used to infer causation; in 15.2% ( = 12) of articles, they were used as proof of mechanism of pathogenesis or treatment; and in 21.5% ( = 17) of articles, they were irrelevant. Case reports were most commonly cited in review articles (38.7%, = 170) and original studies (31%, = 136). "Original studies" were articles in which authors reported original data, excluding case reports.

Conclusions: These results reveal that most citations of case reports are appropriate.