History of outcome measures for myasthenia gravis.

This review illustrates how measurements of clinical status in patients with myasthenia gravis have evolved from clinical descriptions and estimates of mortality rates to more sophisticated evaluative instruments, including numerical rating scales that measure strength, endurance, quality of life, and activities of daily living. The rationale and use of weighting and the importance of patient-reported outcomes are also discussed. The measurement of the steroid-sparing effect of an immunosuppressant is also reviewed.