A longitudinal study of functional disability in a national cohort of patients with polymyositis/dermatomyositis

Arthritis Rheum. 1995 Sep;38(9):1218-24. doi: 10.1002/art.1780380907.


Objective: To analyze changes in functional status and the factors contributing to disability in a national inception cohort of 257 patients with polymyositis/dermatomyositis (PM/DM).

Methods: Data were gathered from patients' self-reports on questionnaires: one concerning disease- and treatment-related complications, and the other concerning disability, as reflected by a disability index (DI) derived from the Health Assessment Questionnaire (HAQ).

Results: Based on certain characteristics that differentiated disability patterns, 3 groups of patients were identified. Group 1 patients (n = 153) were < or = 60 years old and never had avascular necrosis (AVN) or a vertebral compression fracture (CF), Group 2 patients were > 60 and never had AVN or a vertebral CF, and Group 3 patients reported AVN or a vertebral CF irrespective of age. As measured by the HAQ DI, disability increased very gradually over time in Group 1 patients and more rapidly in Group 2 and Group 3 patients. The increase in disability in patients experiencing AVN was greater than that in patients with similar pre-AVN disease characteristics who did not develop AVN (P = 0.003).

Conclusion: In this prospective study of disease course and iatrogenic factors related to functional disability in PM/DM, the HAQ DI increased with disease duration. Corticosteroid-related morbidity, as reflected by the development of AVN or CF, significantly contributed to patient-reported functional disability.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Cohort Studies
  • Dermatomyositis / complications
  • Dermatomyositis / drug therapy
  • Dermatomyositis / physiopathology*
  • Disability Evaluation
  • Disabled Persons*
  • Disease Progression
  • Female
  • Health Status
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Osteonecrosis / complications
  • Polymyositis / complications
  • Polymyositis / drug therapy
  • Polymyositis / physiopathology*
  • Prednisone / administration & dosage
  • Prednisone / therapeutic use
  • Surveys and Questionnaires
  • Time Factors


  • Prednisone