The efficacy of dietary intervention on gastrointestinal involvement in systemic sclerosis: A systematic literature review.

BACKGROUND: Gastrointestinal involvement in systemic sclerosis is common and a major cause of disease-related morbidity. Patients increasingly enquire about dietary modifications that may help with gastrointestinal symptoms. Many clinical practice reviews and treatment guidelines make specific reference to dietary modifications in the management of gastrointestinal involvement in systemic sclerosis. We report the findings of a systematic literature review designed to evaluate the evidence to support dietary modification in the management of gastrointestinal symptoms of systemic sclerosis.

METHODS: A systematic literature review protocol was developed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered with the International prospective register of systematic reviews (CRD42018103549). Standardised searches of EMBASE and MEDLINE were undertaken to identify studies reporting the outcome of dietary modification in the management of gastrointestinal symptoms of systemic sclerosis. Wide heterogeneity in study design, interventions and study outcomes necessitated a qualitative data synthesis.

RESULTS: Our standardised searches identified 1032 articles, of which 3 were deemed eligible for full data extraction. These studies were small (mean 19 subjects per study), single centre, short-term (mean 6 week duration) open-label non-randomised studies examining the role of probiotics, low-fermentable oligo-saccharides, disaccharides, monosaccharides, and polyol (low-FODMAP) diet and highly individualised medical nutrition therapy counselling, respectively. Improvements in patient-reported outcome assessment of gastrointestinal symptoms were reported after intervention with probiotic therapy and low-FODMAP diet but not following tailored dietary and nutritional counselling. The Risk of Bias Assessment Tool for Nonrandomized Studies identified high risk-of-bias for confounding variables and blinding of assessors in each of the three studies evaluated.

CONCLUSIONS: The evidence-base to support dietary modification for gastrointestinal involvement in systemic sclerosis is currently limited and clinical practice guidelines should take a measured approach to such recommendations. The emergence of large patient registries could facilitate the capture of vital practice-based evidence regarding the efficacy of dietary modification in the management of gastrointestinal involvement in systemic sclerosis to inform future clinical practice guidelines.