Inflammatory bowel disease (IBD) is a chronic relapsing immune mediated inflammatory disease (IMID) of the gastrointestinal tract. Like all IMIDs (e.g. rheumatoid arthritis, psoriasis) a complex interaction between a genetically altered immune response, the gut microbiota and environmental factors is causing the disease. Systemic suppression of the immune response with corticosteroids, immunomodulatory, biologicals and combination therapies increases the risk of opportunistic infections in IBD patients.

Data on mild and moderate infections in medically treated IBD patients is scarce, mainly since infections treated by the general practitioner or in an outpatient setting are not systematically registered in real life. To help gastroenterologists with clinical decision making, real world data with long term follow-up concerning the risk for infectious complications, is warranted.

Several observations underline the importance of real world data on mild and moderate infections in medically treated IBD patients. Mild and moderate infections mostly have a benign course, but they take longer to clear and have a large impact on (work)disability and quality of life in IBD patients. Recurrent infections influences peoples willingness to use a drug and negatively effects adherence. Furthermore, recurring mild and moderate infections might prognosticate serious infections, and systematic assessment of all infections could be used to timely adjust treatment regimens and prevent serious infections.

The investigators of this study previously developed a questionnaire on self-reported infections according to the FDA guideline for patient-reported outcome measures (PROM) by interviewing 36 patients with IBD and through input of expert meetings with gastroenterologists, IBD specialists, rheumatologists, immunologists and IBD-nurses. This questionnaire has already been implemented in myIBDcoach, a validated telemedicine system implemented in routine care for over 4000 patients with IBD in the Netherlands. Assesment of reliability and validity are the last steps in validation of this remote monitoring tool.

In the current study the investigators aim to:

1. Assess the reliability, construct validity and criterion validity of a remote monitoring tool (questionnaire) for infections as last step in the validation
2. Assess the relative risk of all infections (mild, moderate and severe) in a real-life population for IBD patients on different maintenance treatments
3. Identify the predictors and risk factors of mild and moderate infections.
4. Assess the relation between patient reported infections and the risk for serious infectious complications

Inclusion Criteria:

• Age ≥ 18 years and diagnosed with IBD
• Included in eHealth clinical care-pathway using myIBDcoach

Exclusion Criteria:

• Patients with insufficient knowledge of the Dutch language
• Patients not able to provide written informed consent

Adults with medically treated inflammatory bowel disease (IBD) (ulcerative colitis and Crohn's disease) included in the eHealth clinical care-pathway using myIBDcoach and followed on the outpatient clinic of Maastricht University Medical Centre or Zuyderland Medical Centre.

Data will be made available to other researchers on demand. Patients will be asked to give informed consent to share the collected data with third parties for future research.