This prospective cohort study will enrol CID patients assigned for TNF-α inhibitors. At baseline (Pre-treatment), patient characteristics are assessed using patient-reported outcome measures and clinical assessments on disease activity, quality of life, and lifestyle together with registry data on comorbidity and medication. Follow-up will be conducted at week 14-16 after treatment initiation (according to the current Danish standards). Evaluation of a successful treatment outcome response will - for each disease - be based on most frequently used primary endpoints; the major outcome of the analyses will be to detect differences in treatment outcome between patients with specific lifestyle characteristics.