The risk of interstitial lung disease in psoriatic arthritis versus psoriasis: a retrospective nationwide database analysis (2014-24).

Objectives: Psoriasis (PsO) is a systemic autoimmune disease primarily characterized by erythematous plaques on the skin. While extra-dermal manifestations like psoriatic arthritis (PsA) are well recognized, data linking PsO to interstitial lung disease (ILD) remain limited. This study aimed to evaluate whether patients with PsA have a higher risk of developing ILD compared with patients with PsO.

Methods: A retrospective analysis of the TriNetX US database (2014-24) was performed. Adult patients with PsO or PsA treated with systemic immunosuppressive medications were included, excluding those with other autoimmune diseases. ILD risk in PsO and PsA cohorts was compared with a reference population without autoimmune disease. Propensity score matching (PSM) adjusted for age, sex, race, BMI, smoking status and medications known to cause ILD was performed. Baseline immunosuppressive therapies were included in the PSM when comparing PsO and PsA. Statistical significance was determined using the χ² test of independence.

Results: After PSM, PsA patients (n = 13 168) had a significantly higher ILD risk compared with the general population (n = 13 168) (risk ratio [RR] 1.94; 95% CI 1.29-2.92; P = 0.0011). PsO patients (n = 24 039) showed no significant difference in ILD risk compared with controls (n = 23 786) (RR 0.79; 95% CI 0.57-1.08; P = 0.14). PsA (n = 13 838) exhibited an over 1.5 times increase in ILD risk compared with PsO (n = 13 842) (RR 1.52; 95% CI 1.06-2.20; P = 0.0226).

Conclusions: PsA was associated with a significantly higher likelihood of developing ILD compared with PsO without inflammatory arthritis. These findings underscore the importance of respiratory monitoring in PsA and highlight the need for further studies.