Definite IA confirmed by the rheumatologist and based on usual criteria: axSpA (referring to the Assessment of Spondyloarthritis international Society classification criteria (51)), RA (referring to the international classification criteria of RA (52)) or PsA (referring to the ClASsification of Psoriatic Arthritis (CASPAR) criteria (53)), with no restriction for co-morbidities,
have a mobile phone compatible with apps that can track steps,
agree to participate and give informed consent,
ability to read and write in the language of participating country.
You may not be if
Patients who don't speak or read the local language or are not comfortable filling in a Case Report Form in the local language or who don't have a mobile phone compatible with health apps.
