Outcome measures used to assess gastrointestinal tract involvement in adults and children with systemic sclerosis: a scoping review.

OBJECTIVES: The gastrointestinal (GI) tract is commonly affected in children and adults with systemic sclerosis (SSc) leading to substantial morbidity including malnutrition, growth failure, and poorer quality of life. We aimed to identify the GI measures used in SSc, describe their performance characteristics, and assess their applicability for use in juvenile-onset SSc (jSSc) trials. METHODS: We performed a scoping review of GI outcome measures in SSc studies from 1994-2024. Studies with at least one GI outcome measure were included, and test performance details were extracted. RESULTS: From the 159 studies identified, there were 25 outcome measures that assessed the oropharyngeal, oesophageal, gastric, small intestinal, colorectal, nutritional and/or patient-reported GI domains. The vast majority (150/159) were observational studies. The oesophagus was the most-studied segment of the GI tract (97/159). Oesophageal manometry was the most commonly reported measure (56 studies). While manometry consistently differentiated SSc from healthy controls, findings inconsistently correlated with GI symptoms. The University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract 2.0 questionnaire (UCLA GIT 2.0) was the most frequently reported patient-reported outcome (PRO) (34 studies). Very few measures were performed longitudinally or used to assess response to intervention, and only two studies had paediatric-specific outcome data. CONCLUSIONS: We identified a wide array of outcome measures used to assess GI tract involvement in SSc with a paucity of longitudinal and paediatric data. Objective measures of GI tract function correlated poorly with symptoms and PROs, underscoring the need for both to be included in future trials.