Health-related quality of life and work impairment in idiopathic inflammatory myopathies in South Australia

Aim The idiopathic inflammatory myopathies (IIM) are rare autoimmune diseases that are usually chronic and often present with skeletal muscle inflammation and weakness. We sought to examine the impact of IIM in a cohort of 50 South Australian patients on health-related quality of life (HRQOL) and work productivity (WP). We uniquely categorized patients across gender, IIM subtypes, employment status, and also whether there was extramuscular involvement from IIM. Methods Multiple modalities were used, as recommended by the International Myositis Assessment and Clinical Studies Group (IMACS), to assess the impact of IIM, including manual muscle strength testing (MMT-8), the Physician and Patient Global Activity Assessments (PHGAA, PTGAA), Myositis Disease Activity Assessment Tool (MDAAT), and serum creatinine kinase (CK) levels. The impacts of IIM on HRQOL and WP were analyzed using the Medical Outcomes Study 36-items Short Form (SF-36) and Work Productivity and Activity Impairment (WPAI) questionnaires, respectively. Results We found significantly lower HRQOL outcome scores in most of the SF-36 domains when compared to the most recent population norms (P ≤ .01). Physical health was predominantly affected with relative preservation of emotional health. There were also significant associations between MMT-8, PHGAA and PTGAA scores and HRQOL and WP. Conclusions Our findings highlight the significant impact of IIM on HRQOL and WP in a well-characterized cohort of patients with IIM within Australia, and therefore the importance of a holistic approach to the management of these patients.