Standardization of Myasthenia Gravis Outcome Measures in Clinical Practice: A Report of the MGFA Task Force

INTRODUCTION/AIMS: Myasthenia gravis (MG) specific outcome measures are being used in clinical trials to evaluate therapeutic effectiveness. These validated tools are also becoming a necessity in clinical practice, with payors in the US market often requiring them to be used to monitor disease state. There is considerable variation and subjectivity regarding their use. This study aimed to develop consensus-based recommendations for the standardization of MG specific outcome measures in clinical practice. METHODS: A panel of 10 US-based MG specialists developed consensus-based recommendations based on three rounds of formal voting using the UCLA-RAND appropriateness method after surveying myasthenia gravis clinicians and developing a focus group. RESULTS: Twenty one expert consensus statements based on six themes were developed following clinician survey result review and focus group theme development. Some key recommendations include: the MGFA Clinical Classification assesses disease at that examination and should be updated at intervals of 3-6 months to reflect current clinical status. MGFA PIS represents the overall clinical judgment of the evaluator without the requirement for a defined change in scores on any outcome measure. Patient-reported items, such as MG-ADL and MGC, should be referenced to the previous 1 week to optimize recall. Additional recommendations include scoring outcome measures in the presence of co-morbidity, scoring specific physical exam findings, and clarification regarding the administration of outcome measures. DISCUSSION: This method provided expert consensus-based recommendations for the use of MG-specific outcome measures and exam findings to help standardize how they are used in clinical practice.