Patients who are suffer from CIF often develop muscle wasting because of hypercatabolism.The relationship between different nutrition support formulas and lean body mass is still unclear. The purpose of this study is to investigate the relationship between nutrition support and muscle mass and attempt to find the nutrients which will benefit lean body mass in patients with CIF.

Chronic intestinal failure (CIF) is defined as the malabsorption and nutrients deficiency mainly caused by severe gastrointestinal benign diseases such as intestinal fistula, short bowel, and mechanical obstruction and some malignant diseases such as end-stage intra-abdominal or pelvic cancers . CIF is one of the rarest of organ failures all over the world and patients suffer from CIF often requires a prolonged time to recover . Hypercatabolism caused by diseases stress, inflammation and reduced nutrient intake indicates that patients with CIF need long-term nutritional support .

Patients who are suffer from CIF often develop muscle wasting because of hypercatabolism. Moreover, studies showed that low muscle mass and muscle wasting during critical illness are associated with poor clinical outcomes and hampered rehabilitation. Except Resistance training, sufficient nutrients supplement also play important roles in maintaining the skeletal muscle mass. Guidelines recommended that nutritional support regimens in patients should be individualized and adjusted over time based on formal nutritional assessment . However, almost all guidelines only recommended the total energy and protein requirements based on the results of basal metabolic rate (BMR) and nitrogen balance rather than the lean body mass . The relationship between different nutrition support formulas and lean body mass is still unclear.

The purpose of this study is to investigate the relationship between nutrition support and muscle mass and attempt to find the nutrients which will benefit lean body mass in patients with CIF.

All adult CIF patients (age ≥18 years) receiving nutrition support were included. The exclusion criteria were hepatic insufficiency (alanine transaminase/aspartate transaminase ratio 200% above normal range or bilirubin >3 mg/dL), renal insufficiency (serum creatinine [Scr] >1.5 mg/dL), acute or life-threatening diseases (e.g., shock, collapse, stroke, coma of unknown etiology, or recent cardiac infarction), and pregnant or breast-feeding women. The study was approved by the ethics committee of Jinling Hospital, Medical School of Nanjing University.

The lean body mass include soft lean mass (SLM), skeletal muscle mass (SMM) and fat free mass (FFM) which were measured and recorded by body composition analyzer (InBody S10, Biospace) at the time of admission and discharge respectively.The deviation of lean body mass was calculated by the difference between admission and discharge, and then symbolized as ∆SLM, ∆SMM and ∆FFM. Basic and nutritional information of CIF patients was measured weekly after hospital admission, including age, sex, BMI, NRS-2002 score, SGA grade, etiology of malnutrition, daily energy & protein intake via EN & PN.

Inclusion Criteria:

- All adult CIF patients (age ≥18 years) receiving nutrition support were included

Exclusion Criteria:

- Hepatic insufficiency (alanine transaminase/aspartate transaminase ratio 200% above normal range or bilirubin >3 mg/dL), renal insufficiency (serum creatinine [Scr] >1.5 mg/dL), acute or life-threatening diseases (e.g., shock, collapse, stroke, coma of unknown etiology, or recent cardiac infarction), and pregnant or breast-feeding women

Patients treated at a single clinical nutrition center of a tertiary referral hospital in China to investigate the relationship between nutrients and muscle mass in CIF patients. The data used were accumulated at the center between September 2013 and September 2017.