Adult participant (18 years and over)

* treated for one of the following conditions: RA, AS, PsA, CD, UC.

* either active substance naïve or treated with the originator or another biosimilar at baseline.

* for whom the treating physician has decided to treat by (naïve) or switch from originator or another biosimilar to Flixabi or Imraldi.

* participants who had initiated Flixabi or Imraldi at most 12 months before the baseline will also be included in the cohort.

Paediatric participants (6-17 years):

* treated for one of the following conditions: CD, UC.

* either active substance naïve or treated with another biosimilar at baseline.

* for whom the treating physician has decided to treat by (naïve) or switch to Flixabi (for both indications) or Imraldi (only for Crohn's disease).

* participants who had initiated Flixabi or Imraldi at most 12 months before the baseline will also be included in the cohort.

One-year Persistence to Treatment of Participants Receiving Flixabi or Imraldi: a French Cohort Study