Epidemiology of myositis.

Area of Science:

• Rheumatology
• Immunology
• Epidemiology

Background:

• Idiopathic inflammatory myopathies (IIMs) are rare autoimmune disorders causing muscle weakness and systemic effects.
• Understanding IIM epidemiology is crucial for disease management and public health.
• Recent advancements have improved disease classification and identified key prognostic factors.

Purpose of the Study:

• To review and synthesize current epidemiological data on IIMs.
• To focus on incidence, prevalence, classification, and clinical outcomes.
• To highlight the impact of myositis-specific autoantibodies (MSAs) on disease prognosis.

Main Methods:

• Systematic literature review of recent epidemiological studies on IIMs.
• Analysis of data on incidence and prevalence rates.
• Examination of disease classification criteria and clinical outcome data.

Main Results:

• IIM incidence ranges from 0.2 to 2 per 100,000 person-years.
• Myositis-specific autoantibodies (MSAs) aid in risk stratification; anti-MDA5 positive dermatomyositis (DM) correlates with interstitial lung disease.
• IIM patients face increased risks of cardiovascular disease and malignancy.

Conclusions:

• IIMs are complex, impacting patient quality of life and requiring increased awareness.
• Enhanced classification and understanding of MSAs are vital for early diagnosis and personalized treatment.
• Further epidemiological research is needed to uncover mechanisms and guide interventions.