Less is more, or almost as much: A 15-item quality-of-life instrument for myasthenia gravis

We describe the process whereby a recently developed myasthenia gravis (MG)‐specific quality‐of‐life (QOL) instrument was reduced from 60 items to 15 items while maintaining potential usefulness in the clinic and in prospective treatment trials. In data from a recently completed prospective trial of mycophenolate mofetil (MMF) in MG, the MG‐QOL15 correlated as highly as the 60‐item MG‐QOL for physical and social domains of the 36‐item health survey of the Medical Outcomes Study Short Form (SF‐36). Correlation coefficients for the MG‐QOL15 were similar to the 60‐item MG‐QOL for the Quantitative Myasthenia Gravis (QMG), MG‐specific Manual Muscle Testing (MG‐MMT), and the MG‐specific Activities of Daily Living (MG‐ADL) scores at week 0 and for change in scores from week 0 to week 12 in the MMF trial. Using the physician global impression at week 12 of the trial as the “gold standard,” the MG‐QOL15 demonstrated high sensitivity. Because the MG‐QOL15 instrument can be quickly and easily administered and interpreted, it is a potential QOL measure for treatment trials and the clinical evaluation of patients with MG. Muscle Nerve, 2008