Fatigue is a common symptom and a leading concern in patients with inflammatory bowel disease (IBD) and often persists despite clinical and endoscopic remission.

This study evaluates the metabolomic profile of fatigued patients with IBD.

To date, there is only one non-published study using metabolomics in quiescent IBD patients with and without fatigue.

The investogators designed this study to examine if there are metabolomics factors associated to fatigue in IBD patients.

This study was performed with plasma samples from IBD patients recruited in a previous study after informed consent. (1) IBD outpatients attending the Hospital de Sabadell Gastroenterology Day-care unit were consecutively included for analytical monitoring of immunosuppressant treatment or infliximab infusion.

The investigators recorded demographic data, IBD classification according to the Montreal classification, and history of drug administration. In addition, clinical activity of the disease was measured using the Harvey-Bradshaw score for Crohn's disease (CD) and the modified Mayo score for ulcerative colitis (UC). The "Functional Assessment of chronic Illness Therapy-Fatigue" (FACIT-F) was used to assess fatigue.

Inclusion Criteria:

- Inflammatory bowel disease diagnosed at least 6 months before the study (diagnosed by clinical, laboratory , endoscopic and histological criteria) .

Exclusion Criteria:

• Age below 18 years.
• Refusal to give written informed consent prior to participation
• Active infection at the time of inclusion.
• Concomitant diseases not related to IBD (e.g., cancer, heart disease, pulmonary disease) that might contribute to the presence or the severity of fatigue.
• Active flare of IBD in the last 3 months.

This study was performed with plasma samples from IBD patients recruited in a previous study after informed consent.