[Informativity of French web forums for the evaluation of side effects of baclofen]

To evaluate the informativity, quality of French discussion forums for evaluation of baclofen safety.

We evaluated the quality of potential pharmacovigilance case reports associated to baclofen in 22 French discussion forums. We compared the informativity concerning the patient, treatment, seriousness and expectedness of adverse events described on these posts, with similar information coded in case reports from the French pharmacovigilance database (FPVD).

A total of 782 potential case reports were identified among 2621 French language forums' posts. Cases in the FPVD were significantly more informative than web forums' posts for patient information (3%/6% vs. 88% for the age/class of age and 46% vs. 99% for the gender), treatment duration (9% vs. 24%) and outcome of the ADR (1% vs. 64%). But both indication and dose were more frequently retrieved in forums than in the FPVD (67% vs. 24% and 27% vs. 9%, respectively). Cases from web forums were significantly more frequently non-serious than the FPVD's ones (38% vs. 0.7%). Adverse events were significantly more often unexpected in forums than in the FPVD (43.8% vs. 11.6%).

Indication and posology were more often documented in posts than in case reports which makes forums an interesting resource for monitoring use of baclofen. While posts contain more unexpected events, informativity is low which makes causality assessment difficult. Nevertheless, we consider forums as a secondary, but complementary source for pharmacovigilance about baclofen.