Epidemiology of connective tissue disorders

Area of Science:

• Rheumatology
• Epidemiology

Background:

• Prevalence and incidence of connective tissue disorders (CTDs) show significant variability.
• Methodological differences in studies, including duration, diagnostic criteria, and country, contribute to this variability.
• Established classification criteria are crucial for identifying patients with systemic rheumatic diseases, despite not being designed for individual diagnosis.

Purpose of the Study:

• To review the reported prevalence and incidence of various connective tissue disorders.
• To highlight factors influencing variability in prevalence data.
• To emphasize the role of classification criteria in identifying CTDs.

Main Methods:

• Literature review of studies reporting prevalence and incidence of CTDs.
• Analysis of factors contributing to variability in reported data.
• Discussion of the utility of classification criteria in research settings.

Main Results:

• Sjögren's syndrome exhibits the highest prevalence (0.5-3%).
• Systemic lupus erythematosus (SLE) prevalence is estimated at 15-50 per 100,000, with a higher incidence in women aged 15-40.
• Systemic sclerosis prevalence varies significantly; polymyositis and dermatomyositis are rare.

Conclusions:

• Study methodology significantly impacts reported prevalence rates for CTDs.
• Accurate classification criteria are indispensable tools for research and identification of patients with CTDs.
• Further standardization in methodology may improve understanding of CTD epidemiology.