Chronological order of appearance of immune mediated inflammatory diseases relative to diagnosis of psoriasis

Abstract Background Psoriasis is a common inflammatory skin disease which is associated with several immune-mediated inflammatory diseases (IMIDs), however little is known of the chronology of the disease development. Objective To investigate the chronology of IMIDs relative to psoriasis. Methods We utilized routinely collected data from Danish nationwide administrative registries to examine the occurrence of IMIDs in patients with psoriasis (n=10,923) and general population controls (n=109,230). Results Approximately 20% of patients with psoriasis developed at least one IMID, with a fivefold increased risk compared with the general population. Most IMIDs occurred before the diagnosis of psoriasis, except for psoriatic arthritis. Psoriasis was significantly associated with having multiple IMIDs (OR 15.2; 95% CI 11.6-20.0). HLA-B27 positivity was significantly more frequent among psoriasis patients. Limitations Clinical measurements were unavailable. Conclusion IMIDs occur frequently in patients with psoriasis and most are diagnosed before psoriasis. The observed chronology may represent important mechanisms of disease development.