Félicitons E Turner et son équipe pour la constance de ses recherches comparant les données objectives des agences de santé (FDA pour Food and Drug Administration) et les publications destinées aux professionnels de santé. Depuis 2008 et son article princeps du New England Journal of Medicine, il apporte des preuves montrant que la réalité est cachée aux professionnels, et nous avons publié plusieurs billets sur ces travaux. Les premiers travaux étaient sur les antidépresseurs, et maintenant ce sont les anxiolytiques !
Il s’agit du Xanax, l’une des benzodiazépines les plus prescrites. Il y a tous les détails dans cet article de 8 pages, et je reprends ci-contre une image qui fait très peur, ainsi que le résumé ci-dessous. Les commentaires sur PubPeer apportent de nombreux compléments utiles. Classique et simple : selon la littérature 100 % des essais montrent l’efficacité de l’alprazolam, selon la FDA, c’est 20 % !
Objective: To test for publication bias with alprazolam, the most widely prescribed benzodiazepine, by comparing its efficacy for panic disorder using trial results from (1) the published literature and (2) the US Food and Drug Administration (FDA).
Methods: From FDA reviews, we included data from all phase 2/3 efficacy trials of alprazolam extended-release (Xanax XR) for the treatment of panic disorder. A search for matching publications was performed using PubMed and Google Scholar. Publication bias was examined by comparing: (1) overall trial results (positive or not) according to the FDA v. corresponding publications; (2) effect size (Hedges’s g) based on FDA data v. published data.
Results: The FDA review showed that five trials were conducted, only one of which (20%) was positive. Of the four not-positive trials, two were published conveying a positive outcome; the other two were not published. Thus, according to the published literature, three trials were conducted and all (100%) were positive. Alprazolam’s effect size calculated using FDA data was 0.33 (CI95% 0.07–0.60) v. 0.47 (CI95% 0.30–0.65) using published data, an increase of 0.14, or 42%.
Conclusions: Publication bias substantially inflates the apparent efficacy of alprazolam XR.