Assessment of disease activity and its sequelae in children and adults with myositis.

Validated, comprehensive measures for assessing disease activity and its irreversible sequelae, known as disease damage, have not been developed for the idiopathic inflammatory myopathies (IIM), thus limiting our capacity to assess individual patients and responses to therapies. This review summarizes current approaches for assessing disease activity and damage in the idiopathic inflammatory myopathies and speculates on possibly useful novel approaches for the future. Disease activity and damage indices that combine a number of these assessments are proposed for use in all therapeutic trials. Methods for assessing target organs of the idiopathic inflammatory myopathies will likely evolve as more sensitive and specific measures are developed that can distinguish active inflammation from the irreversible effects of disease.