The Association Between SARS-CoV-2 Exposure, COVID-19 Vaccination and Psoriatic Arthritis-A Nested Case-Control Study

Background/Objective: The emergence of the COVID-19 pandemic has raised significant concerns regarding its impact on immune-mediated diseases, particularly with respect to disease induction and exacerbation. We aimed to investigate the potential association between SARS-CoV-2 infection and COVID-19 vaccination and the development of Psoriatic Arthritis (PsA). Methods: A retrospective nested case-control study in a cohort of 3,122,602 adults without a diagnosis of PsA was conducted using a database of a large health care provider. Newly diagnosed patients with PsA aged 18 years and older were identified from the database between 1 January 2021 and 30 June 2022 and were matched by age and sex to 10 non-PsA controls. Patients were tracked to assess their exposure to SARS-CoV-2 within six months prior to diagnosis (inception date). The primary outcome of exposure to SARS-CoV-2 was compared in the cases and controls. Univariate and multivariate conditional logistic regression analyses were performed, adjusting for Body Mass Index (BMI), smoking, socioeconomic status (SES), the Charlson comorbidity index, ethnicity, psoriasis and COVID-19 vaccination status within six months. Results: Overall, 718 patients had a new diagnosis of PsA and were matched with 7180 controls. SARS-CoV-2 exposure among PsA cases was (N = 88/718, 12.3%) compared to controls (N = 755/7180, 10.5%), the difference was not statistically significant (p = 0.115). No statistically significant association was found between SARS-CoV-2 infection and PsA development after adjusting for all confounders (OR = 1.08, 95% CI [0.76-1.54], p = 0.652). COVID-19 vaccination was also not associated with PsA development (OR = 1.10, 95% CI [0.86-1.41], p = 0.45). Conclusions: This study found no statistically significant association between SARS-CoV-2 exposure or COVID-19 vaccination and PsA development within six months post-exposure; however, small differences cannot be excluded.