Department of Psychology and Behavioural Sciences

The placebo response in myasthenia gravis assessed by quantitative myasthenia gravis score: A meta-analysis

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


  • Elisa Frisaldi, University of Turin Medical School
  • ,
  • Aziz Shaibani, Nerve & Muscle Center
  • ,
  • Jan Vollert, Imperial College London, London, UK., Universität Heidelberg
  • ,
  • Bruno Ferrero, University of Turin Medical School
  • ,
  • Roberta Carrino, University of Turin Medical School
  • ,
  • Hayan Dhamer Ibraheem, Nerve & Muscle Center
  • ,
  • Lene Vase
  • Fabrizio Benedetti, University of Turin Medical School, Plateau Rosà Laboratories

Introduction: This meta-analysis investigates the placebo response in generalized myasthenia gravis (MG) trials by means of Quantitative Myasthenia Gravis (QMG) scores. Methods: PubMed, Scopus, Web of Science, Cochrane Controlled Trial Register, and EMBASE were searched. QMG score, dropouts rate, adverse events (AEs), and AEs responsible for dropouts were examined, together with treatment moderators. Results: The magnitude of placebo response showed an effect size of 0.24, which was significantly lower than 0.67 of the drug response (P = 0.019). Furthermore, the forest plot revealed that, overall, active treatments showed a significantly higher impact on QMG scores than placebos. Conclusions: Placebo and drug responses in MG trials are small and moderate, respectively. The lack of MG trials with a pure placebo arm or a no-treatment control arm made it impossible to disentangle improvements due to the placebo psychological effect from other effects such as natural history and/or regression to the mean. Muscle Nerve 59:671–678, 2019.

Original languageEnglish
JournalMuscle and Nerve
Pages (from-to)671-678
Number of pages8
Publication statusPublished - 2019

    Research areas

  • clinical trials, meta-analysis, myasthenia gravis, neuromuscular disorders, placebo effect, placebo response

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