To investigate the prevalence of loneliness among patients with IA with a specific focus on the associations with disease activity and impact. We used data from a Danish cross-sectional survey comprising information on socio-demographics, mental health status, and social contacts among 12 713 patients with IA [rheumatoid arthritis (RA)/psoriatic arthritis (PsA)/axial spondylarthritis (axSpA)]. Data were linked to the DANBIO Rheumatology Registry and the National Patient Registry.