A prospective observational study to assess the energy needs of Ulcerative Colitis patients undergoing total proctocolectomy with ileoanal j-pouch anastomosis.

Total proctocolectomy with creation of ileoanal j-pouch anastomosis is the gold-standard surgical procedure for familial polyposis, for ulcerative colitis unresponsive to medication and for colitis associated with dysplasia requiring total colectomy.

Patients postoperatively face difficulties in maintaining their physical condition and quality of life due to potential complications such as surgical, mechanical, inflammatory and functional disorders increasing the rates of malnutrition. Postoperative changes as regards anthropometric characteristics and nutritional status have not been fully elucidated.

Therefore, the need arises to calculate the energy needs of patients with ileoanal j-pouch anastomosis, given the lack of corresponding data and the possible differentiation of energy needs from a similar group of patients undergoing colorectal surgery.

Of particular interest is the body composition of ileoanal anastomosis patients, which has been studied very little ), and the extent to which their energy needs are met, given dietary restrictions both preoperatively and postoperatively.

It is therefore necessary to determine the energy needs, as well as the degree of their coverage by the diet, of UC patients undergoing proctocolectomy with creation of ileoanal j-pouch anastomosis.

Inclusion Criteria:

• Patients with ulcerative colitis and planned proctocolectomy with ileoanal j-pouch anastomosis surgery or patients who are to undergo subtotal colectomy.
• Age over 18 years.
• Written informed consent to take part in the study.
• Speaking ability in Greek or English.
• Able to get tested fasted;

Exclusion Criteria:

• Age under 18 years.
• Existence of pregnancy.
• Inability to breathe inside the indirect calorimetry mask for the time required for the measurement.
• Use of medications that may affect body metabolism will be evaluated individually (e.g. cortico-steroids etc.)

Patients with Ulcerative Colitis about to undergo proctocolectomy with ileoanal j-pouch anastomosis. As control group, it is planned to enroll patients about to undergo subtotal colectomy, matched with the patient group in terms of gender, age and body mass index.