Abstract Background Psoriasis is a complex autoinflammatory disease that has been associated with atherosclerosis, higher risks of cardiovascular diseases, and electrocardiographic changes. Whether these risk factors lead to higher risks of out-of-hospital cardiac arrest (OHCA) is undetermined. Purpose To investigate whether psoriasis is associated with OHCA. Method Using the nationwide Danish Cardiac Arrest Registry, we identified adult (≥18 years) OHCA patients of presumed cardiac cause with and without psoriasis between June 1st 2001 and December 31st 2019. The association of cardiac arrest was estimated using time-varying Cox regression fitted with a nested case-control design where we matched up to five controls per case on age, sex and year of OHCA and 4 comorbidities: ischemic heart disease, congestive heart failure, cardiovascular risk factors, and major extra cardiac organ disease. In subgroup analyses, the main analysis was repeated in patients with severe psoriasis (presence of inpatient hospital contact during the previous year) as compared to mild psoriasis. Results We included 43,967 OHCA cases and matched with 219,772 controls from the general population. The median age was 72 years, 68% were male and 26% had ischemic heart disease, 21% had congestive heart failure, 57% had cardiovascular risk factors, and 33% had extra cardiac organ disease (Table 1). We identified 1,145 (2.6%) cases and 4,971 (2.3%) controls who had psoriasis. Compared with cardiac arrest cases without psoriasis, cases with psoriasis had similar age and sex distribution, prevalence of ischemic heart disease, and congestive heart failure, but a higher prevalence of cardiovascular risk factors, major extra cardiac organ disease and Charlson score distribution. Psoriasis was significantly associated with higher hazard ratios of OHCA: HR 1.16 [95% confidence interval: 1.08 - 1.23] (Figure 1). Compared to no psoriasis, having severe psoriasis was significantly associated with higher hazard of OHCA: HR 1.98 [95% confidence interval: 1.10 - 3.61], while mild psoriasis was not (Figure 1). Conclusion In this nationwide nested case-control study, psoriasis was significantly associated with increased hazard of out-of-hospital cardiac arrest. Furthermore, the association was only significant with severe psoriasis compared to those without psoriasis, while mild psoriasis was not. This study highlights the importance of examining cardiovascular risk factors and prioritizing prevention of cardiovascular disease in patients with psoriasis.Figure 1Table 1