Background: Malnutrition and gastrointestinal (GI) involvement are common in patients with systemic sclerosis (SSc). Despite malnutrition being common, little is known about its associations and predictors. Although patients are frequently screened and assessed for malnutrition, different clinically applicable assessment modalities in SSc have not been compared. An understanding of the relationship between dietary intake and energy expenditure is important for nutritional assessment and management. However, studies have not compared these. For many years, home parenteral nutrition (HPN) has been used in patients with intestinal failure, but little outcome data exists to support its role in SSc. GI involvement results in dysmotility, the underlying mechanism for the development of which is unknown. However, autonomic dysfunction has been proposed.Aims: To explore aspects of the nutritional assessment and management of patients with SSc. To seek associations and predictors of nutritional decline. To investigate for a link between GI dysmotility and autonomic dysfunction.Methods: Study 1: A retrospective review of the survival and outcome data of patients commenced on HPN over 22 years. Study 2: An assessment of 168 patients recruited over 12 months and restudied after approximately 1 year. Assessment included demographics, clinical data, GI and functional questionnaires, nutrition screening tool, oral aperture, mid-upper arm and 4-site anthropometry, bioelectrical impedance and biochemical testing. Re-study included weight change. Study 3: A 3 day assessment of dietary intake and energy expenditure using food record charts and SenseWear® Armband involving 36 patients recruited to Study 2. Study 4: Patients and matched controls completed GI and autonomic questionnaires, an autonomic battery, a gastric emptying study and postprandial cardiovascular measures and GI sensations and symptoms scores.Results: Study 1: The cumulative probabilities of surviving on HPN at 2, 5 and 10 years were 75%, 37% and 23%. HPN-associated complication rates were low. Study 2: Nutritional screening failed to identify all patients who lost weight. Mid-arm circumference correlated with body mass index (BMI) and weight change. Four-site anthropometry correlated with BMI more strongly (r=0.65 vs. r=0.49) than bioelectrical impedance analysis. Small intestinal, but not oesophageal, involvement correlated with baseline nutritional status. No clear predictors of nutritional decline were identified. Study 3: Predicted energy intakes correlated with measured expenditures, but absolute values differed. Energy intakes did not correlate with expenditures. Study 4: Autonomic measures did not correlate with gastric emptying. However, autonomic results were hindered by patient-related and technical limitations.Conclusion: Nutritional screening tools cannot be relied upon to detect all at risk patients. MAC and 4-site anthropometry may have a role in nutritional assessment. When an accurate appreciation of energy requirements is needed, kinematic monitors should be used rather than predictive equations. For those patients who progress to intestinal failure, HPN is safe and effective. Autonomic studies were inconclusive. However, the autonomic apparatus has been refined for utilisation in more definitive studies in younger patients.