Objective: To compare the quality, relevance, and structure of drug studies published in symposium proceedings that are sponsored by drug companies with 1) articles from symposia with other sponsors and 2) articles in the peer-reviewed parent journals of symposium proceedings; and to study the relation between drug company sponsorship and study outcome.
Design: Cross-sectional studies of clinical drug studies published in symposium proceedings or their parent medical journals.
Measurements: The proportion of articles with no methods sections (which are necessary to assess quality); methodologic quality and clinical relevance scores; and the proportion of articles with outcomes favoring the drug of interest.
Results: Symposia sponsored by single drug companies had more articles without methods sections (10%; 108 of 1064) than did symposia that had other sponsors (3%; 58 of 2314) or symposia that had no mentioned sponsor (2%; 29 of 1663) (P < 0.001). The mean methodologic quality and relevance scores of articles were similar both by type of sponsorship and between articles published in symposia sponsored by single drug companies and articles from the parent journals. Significantly more articles with drug company support (98%; 39 of 40) than without drug company support (79%; 89 of 112) had outcomes favoring the drug of interest (P = 0.01).
Conclusions: Articles in symposia sponsored by single drug companies were similar in quality and clinical relevance to articles with other sponsors and to articles published in the parent journals. Articles with drug company support are more likely than articles without drug company support to have outcomes favoring the drug of interest.