Detailled Information

Isenberg DA, Allen E, Farewell V, et al. International consensus outcome measures for patients with idiopathic inflammatory myopathies. Development and initial validation of myositis activity and damage indices in patients with adult onset disease. Rheumatology (Oxford). 2004;43(1):49-54.

This study summarizes the main outcome measures in adult and juvenile dermatomyositis, polymyositis, and inclusion body myositis.

This study tests the interrater reliability, internal consistency and aspects of validity of the myositis damage index (MDI).

This tool assesses the degree of disease damage of various organ systems. It is composed of a series of organ-specific questions relating to the presence or absence of a given sign or symptom or problem to measure the extent of damage, and an overall rating of the disease damage of each system using a 10 cm. visual analogue scale to measure the severity of damage. The MDI is intended to be used in patients with adult and juvenile dermatomyositis (DM), polymyositis (PM), and inclusion body myositis (IBM). It measures specific manifestations in 11 organ systems.

For the VAS, scores for each organ system are determined by measuring the distance of the vertical line from the left-hand side of the horizontal VAS. The length of the VAS should also be measured so that the score can be adjusted to a denominator of 10 cm. For items in the damage index, the score is 1 point if present and 0 if absent. In order for an item to be scored as a damage item, the problem must have been present for at least 6 months and must be expected to persist or be irreversible and not treatable with immunosuppressive medication.