Unraveling the connection: Uveitis prevalence and risk factors in psoriasis patients - a population-based study

The association between uveitis and spondyloarthropathy (SpA)-related conditions is well-established. However, evidence describing the link between uveitis and psoriasis, and psoriasis without concomitant SpA-related conditions is scarce and conflicting. This large-scale population-based study sought to describe the prevalence and features of uveitis among psoriasis patients in Israel as well as investigating the risk for uveitis in different subgroups of psoriasis patients compared to the general population. We conducted a retrospective study utilizing the electronic database of the Meuhedet Health Maintenance Organization. The study included all patients diagnosed with psoriasis between 2000 and 2020, each patient was matched with four controls based on age, sex, place of residence, and index date. Logistic regression models were employed to assess the association between psoriasis and uveitis while adjusting for the presence of SpA-related conditions. A total of 61 003 psoriasis patients and 244 012 matched controls were included. The prevalence of uveitis was 1.3% versus 1.1% respectively (OR  1.12; 95% CI 1.10-1.30; p < 0.001). When adjusting to psoriasis severity, concurrent SpA, and psoriasis treatment no significant association was found. The rates of uveitis among psoriasis patients with concurrent SpA-related conditions was 3.2% compared to 1.4% in controls without psoriasis or SpA (OR 2.38; 95% CI 2.00-2.83; p < 0.001), while in psoriasis patients without SpA, the rate of uveitis was 1.0% and was similar to controls. Although crude rates of uveitis were higher in patients with severe psoriasis compared to mild psoriasis (2.1% vs. 1.1%), after adjustment, no significant association compared to controls was found in either group. Our findings suggest that the positive association between psoriasis and uveitis is primarily mediated by the coexistence of other SpA-related conditions. These findings imply the presence of a shared pathogenetic mechanism and set the direction for a phenotypic-targeted screening strategy.