Psoriasis in the U.S. Medicare population: prevalence, treatment, and factors associated with biologic use

Psoriasis is a common chronic inflammatory disorder, primarily of the skin. Despite an aging population, knowledge of the epidemiology of psoriasis and its treatments among the elderly is limited. We examined the prevalence of psoriasis and its treatments, with a focus on biologics and identification of factors associated with biologic use, using a nationally representative sample of Medicare beneficiaries in 2011. On the basis of several psoriasis identification algorithms, the claims-based prevalence for psoriasis in the United States ranged from 0.51 to 1.23%. Treatments used for moderate-to-severe psoriasis (phototherapy, oral systemic, or biologic therapies) were received by 27.3% of the total psoriasis sample, of whom 37.2% used biologics. Patients without a Medicare Part D low-income subsidy (LIS) had 70% lower odds of having received biologics than those with LIS (odds ratio 0.30; 95% confidence interval, 0.19-0.46). Similarly, the odds of having received biologics were 69% lower among black patients compared with white patients (0.31; 0.16-0.60). This analysis identified potential financial and racial barriers to receipt of biologic therapies and underscores the need for additional studies to further define the epidemiology and treatment of psoriasis among the elderly.