A new approach and conceptual model for understanding systemic sclerosis-associated gastrointestinal symptoms

INTRODUCTION: Our understanding of the pathogenesis of systemic sclerosis-associated gastrointestinal (SSc-GI) disease is limited. This has hindered progress in the management of SSc-GI disease as objective measures to assess the extent of disease and monitor treatment response are lacking. We propose a conceptual model for understanding pathogenic mechanisms of SSc-GI symptoms. A multi-dimensional model of understanding the etiology of symptoms may enable an improved understanding of patients' symptom experience and opportunities for development of therapies. AREAS COVERED: We reviewed literature from the past 5 years pertaining to SSc-GI symptoms and their etiology. When gaps in data were identified, we evaluated research from general gastroenterology and inflammatory bowel disease. We describe evolving concepts of pathologic mechanisms of SSc-GI disease, including motility, the gut-brain axis, diet, the microbiome and pelvic floor dysfunction. EXPERT OPINION: A broad understanding of factors that contribute to symptoms is necessary to understand the experience of SSc-GI disease and develop targeted therapies that modify the SSc-GI disease course. Due to a lack of objective clinical outcome measures in SSc-GI disease, qualitative research methodologies are essential for deepening our understanding of these patient experiences and developing new outcome measures to enable trials to establish an evidence-based approach to SSc-GI disease.