Development of a conceptual model of early systemic sclerosis (scleroderma)

Area of Science:

• Rheumatology
• Medical Sociology
• Patient-Reported Outcomes

Background:

• Systemic Sclerosis (SSc) is a rare, heterogeneous connective tissue disorder with limited cutaneous (lcSSc) and diffuse cutaneous (dcSSc) subtypes.
• Existing models lack comprehensive representation of the diverse patient experiences in SSc.
• A robust conceptual model is crucial for advancing outcome measurement strategies in SSc research.

Purpose of the Study:

• To identify and conceptualize key SSc disease symptoms and experiences.
• To develop a comprehensive conceptual model of SSc symptoms that reflects patient heterogeneity.
• To support the development of measurement instruments for SSc clinical trials.

Main Methods:

• A targeted literature review identified concepts for diffuse cutaneous SSc (dcSSc).
• Semi-structured concept elicitation interviews were conducted with 44 adult patients with lcSSc and dcSSc.
• A preliminary dcSSc symptom model was refined into a final conceptual SSc symptoms model based on interview data.

Main Results:

• 112 unique symptoms across 13 domains were reported by patients, with 26 new to the literature.
• Hand and skin symptoms were universal; gastrointestinal and pain symptoms were highly prevalent (>95%).
• Despite subtype differences, significant overlap in reported symptoms, including skin fibrosis and hand issues, supports a unified model.

Conclusions:

• The developed conceptual model effectively captures the heterogeneous symptoms and lived experiences of patients with Systemic Sclerosis.
• The model encompasses both lcSSc and dcSSc subtypes, providing a unified framework.
• This model can guide the selection or creation of instruments for measuring patient experiences in clinical trials.