Objective
Extensive studies on health-related quality of life (HRQOL) in idiopathic inflammatory myopathies (IIM) are lacking. Our objective was to document HRQOL and to identify factors associated with a reduced HRQOL in IIM patients.
Methods
A total of 1,715 patients (median age 49.9, 70% female, 87% Caucasian) who met probable or definite Bohan and Peter or Griggs criteria for myositis were included from the MYOVISION registry. HRQOL was ascertained via the SF-12v2® Health Survey questionnaire. HRQOL physical and mental summary scores (PCS and MCS, respectively) in relation to different patient and disease characteristics were compared to scores from the matched normative data from the U.S. general population and rheumatoid arthritis (RA) patients. Bivariate and multiple linear regression analyses were performed to assess the association between HRQOL and patient and disease parameters.
Results
The mean summary scores of the SF-12v2® were significantly lower in IIM as compared to the normative and RA populations. A diagnosis of inclusion body myositis, older age, patient-reported negative effect of disease on work, presence of another concurrent autoimmune disease, polypharmacy, and IIM-associated lung disease and joint involvement were all significantly associated with lower PCS scores. Lower MCS scores were associated with joint involvement and a negative effect on work.
Conclusion
In this large study of patient-reported outcomes in IIM, an association was found between multiple disease characteristics and reduced HRQOL, mostly in the physical domain. In the United States, HRQOL in IIM patients was lower compared to the general population and to RA patients.