Disease severity and therapy as predictors of cardiovascular risk in psoriasis: a population-based cohort study

Background Previous studies suggest an increased risk of cardiovascular disease in psoriasis, but the relative contributions of traditional risk factors and markers of disease severity are unclear. We examined the effect of psoriasis disease characteristics on cardiovascular risk after adjusting for traditional cardiovascular risk factors. Methods Study populations included (a) case-cohort sample of 771 patients nested within a population-based psoriasis incidence cohort, and (b) cohort of 1905 patients with incident and prevalent psoriasis patients. Both cohorts were followed-up to ascertain disease and treatment characteristics, traditional cardiovascular risk factors and cardiovascular outcomes. Cox proportional hazards regression models were used to identify predictors of cardiovascular outcomes. Results After adjusting for traditional risk factors, increasing number of psoriasis-affected body sites at disease onset (HR: 1.53 per additional site, 95% CI: 1.20, 1.95) was significantly associated with an increased risk of cardiovascular outcomes. Phototherapy (HR: 3.76, 95% CI: 2.45, 5.77) and systemic therapy (HR: 2.17, 95% CI: 1.50, 3.13) were associated with a higher risk of cardiovascular outcomes in univariate analyses, but these relatively strong associations disappeared after adjusting for cardiovascular risk factors. Conclusions Increasing number of psoriasis-affected body sites may be a severity indicator in psoriasis and is associated with an increased cardiovascular risk. Due to low number of patients exposed to systemic therapy, this study had limited power to examine the effect of treatment on cardiovascular risk. Strong associations with phototherapy and systemic therapy suggest that the cardiovascular risk in psoriasis is confined to patients with severe disease. Received: 7 December 2010; Accepted: 18 March 2011