Arthritis as an important determinant for psoriatic patients to develop severe vascular events in Taiwan: a nation-wide study.

Background: Psoriasis is an important systemic inflammatory disease that often leads to severe vascular diseases. This study was launched to determine if joint involvement affects incidence of vascular comorbidities in psoriatic patients. In addition, potential vasculo-protective effects of methotrexate in psoriatic patients were also evaluated.

Method: A population-based retrospective cohort study was conducted using the Taiwanese National Health Insurance database spanning from 1996 to 2006. Accordingly, 7648 and 284 psoriatic patients without or with arthritis, respectively, were identified. To ensure the temporal relationship between different events, those with date of first diagnosis psoriasis during the year of 1996 were excluded from subsequent analyses. In addition, those with diagnosis of cerebrovascular or cardiovascular diseases prior to onset of psoriasis were also excluded from relevant subsequent analyses.

Result: Taking psoriatic patients without arthritis as the referent group, the hazard ratio for incident cerebrovascular disease was 1.82 (95% CI = 1.17-2.82) for psoriatic patient with arthritis. In addition, psoriatic patients without arthritis who had methotrexate treatment showed reduced risks for incident cerebrovascular disease as compared with those with no arthritis and had received no methotrexate/retinoid treatment. Similar analyses were performed on cardiovascular diseases, and equivalent results were obtained.

Conclusion: Our study indicated that arthritis is a potential determinant for psoriatic patients in terms of incident vascular comorbidities. In addition, methotrexate treatment may be associated with reduced risks for development of severe vascular diseases in psoriatic patients without arthritis. Further studies should focus on the clinical complications associated with psoriatic patients with or without arthritis.