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Myasthenia Gravis Composite - MGC
Availability
Please visit this website for more information about the instrument: Myasthenia Gravis Composite (MGC)
Classification
Core: Myasthenia Gravis (MG)
Short Description of Instrument
The Myasthenia Gravis Composite scale (MGC) is a reliable and valid disease-specific scale for measuring the clinical status of patients with Myasthenia Gravis (MG) in the practice setting and clinical trials. (Burns et al., 2008; Burns, 2010; Burns et al., 2010; Muscle Study Group, 2008; Sanders et al., 2008)
Comments/Special Instructions
The MGC covers the 10 important functional domains most frequently affected by MG. (Burns et al., 2008) The domains covered include:
    • Ocular (physician examination - 3 items)
    • Bulbar (patient history - 3 items)
    • Respiratory (patient history - 1 item)
    • Neck (physician examination - 1 item)
    • Limb (physician examination - 2 items)
Relevant items were selected from existing MG-specific scales, Quantitative Myasthenia Gravis, QMG, Manual Muscle Test for MG, MG-MMT and Myasthenia Gravis Activities of Daily Living, MG-ADL. (Burns et al., 2008) The MGC scale is available in Table 1 in Burns et al., 2010.
Scoring and Psychometric Properties
Scoring: Scores are based on a 4-point Likert/Likert-type Scale from 0 to 2, 3, 4, 5, 6 or 9 according to the item Response options are weighted. Types of scores include Global score: sum of all item scores, ranging from 0 to 50, Scores by domains and Scores by items.
 
Psychometric Properties: See Burns et al., 2008 and Sadjadi et al., 2012 for a discussion of psychometric properties.
Rationale/Justification
Strengths: The MGC takes less than 5 minutes to administer and is validated in both the practice and clinical trial settings.
 
Weaknesses: The MGC does not measure clinical change.
References
Key References:
Burns TM, Conaway MR, Cutter GR, Sanders DB; Muscle Study Group. Construction of an efficient evaluative instrument for myasthenia gravis: the MG composite. Muscle Nerve. 2008 Dec;38(6):1553-62.
 
Burns TM, Conaway M, Sanders DB; MG Composite and MG-QOL15 Study Group. The MG Composite: A valid and reliable outcome measure for myasthenia gravis. Neurology. 2010 May 4;74(18):1434-40.
 
Sadjadi R, Conaway M, Cutter G, Sanders DB, Burns TM; MG Composite MG-QOL15 Study Group. Psychometric evaluation of the myasthenia gravis composite using Rasch analysis. Muscle Nerve. 2012 Jun;45(6):820-5.
 
Additional References:
Burns TM. History of outcome measures for myasthenia gravis. Muscle Nerve. 2010 Jul;42(1):5-13.
 
Muscle Study Group. A trial of mycophenolate mofetil with prednisone as initial immunotherapy in myasthenia gravis. Neurology. 2008 Aug 5;71(6):394-9.
 
Sanders DB, Hart IK, Mantegazza R, Shukla SS, Siddiqi ZA, De Baets MH, Melms A, Nicolle MW, Solomons N, Richman DP. An international, phase III, randomized trial of mycophenolate mofetil in myasthenia gravis. Neurology. 2008 Aug 5;71(6):400-6.
 
Document last updated October 2024