New-onset Autoimmune Diseases in Patients with Prurigo Nodularis: A Global-federated Retrospective Cohort Study

Prurigo nodularis (PN) has been associated with autoimmune diseases, though longitudinal data are limited. This study investigates the risk of autoimmune disease development in PN patients using a global electronic health record database. This retrospective cohort study analysed data from the Global Collaborative Network within the TriNetX research network. Adults (≥ 18 years) with PN were compared with propensity score-matched controls without PN. Matching considered age, sex, comorbidities, race, and socioeconomic status. Patients with prior autoimmune diseases or cancers were excluded. Incident autoimmune diseases, including systemic lupus erythematosus (SLE), Sjögren's syndrome, psoriasis, ankylosing spondylitis (AS), rheumatoid arthritis (RA), Crohn's disease (CD), and ulcerative colitis (UC), were evaluated using hazard ratios (HR). Among 17,963 PN patients and the same amount of matched pairs, PN patients had higher risks for SLE (HR: 2.16, 95% CI: 1.44-3.24), Sjögren's syndrome (HR: 1.86, 95% CI: 1.33-2.59), and psoriasis (HR: 3.20, 95% CI: 2.58-3.97). Stratified analysis revealed that female PN patients had higher risks for SLE and Sjögren's syndrome, while psoriasis risk was elevated in both sexes, especially in males. Risks for AS, RA, CD, and UC were not significant. Sensitivity analyses validated these findings. In conclusion, PN is linked to increased risks for SLE, Sjögren's syndrome, and psoriasis, highlighting the need for proactive screening and management of autoimmune diseases in PN patients.