Initiation, Switching, and Cessation of Psoriasis Treatments Among Patients with Moderate to Severe Psoriasis in the United States.

Background: Psoriasis patients frequently switch among multiple therapies while managing their psoriasis. Determining treatment transitions is fundamental to understanding how patients access and use treatments.
Objective: We aimed to identify patterns of treatment transitions of US patients with moderate to severe psoriasis over 5 years.
Methods: This was a retrospective, longitudinal cohort study in which US patients aged ≥18 years who had at least one psoriasis claim (International Classification of Diseases, Ninth Revision [ICD-9] diagnosis) were continuously enrolled in a health plan between October 2007 and September 2012. Data from eligible patients were projected to reflect the total US insured population with moderate to severe psoriasis, and the proportions of patients who started, stopped, switched, and restarted treatment at any time between September 2011 and September 2012 were analyzed. Treatment categories were biologics, traditional oral systemics, topicals, phototherapy, lapsed from treatment, and treatment-naive.
Results: There were 8.9 million patients in the claims database, of whom 0.9 million (10.4%) had a psoriasis diagnosis and 46,369 (0.5%) met the inclusion criteria. When projected, 1.7 million insured patients had moderate to severe psoriasis. Of these, an estimated 807,000 patients had lapsed treatment, an additional 346,000 were receiving treatment, and 547,000 were defined as being treatment-naive. A total of 81,000 of 346,000 patients had switched treatment in the preceding year. In addition, many patients stopped (438,000) and restarted (384,000) treatment in the 12-month period.
Conclusion: Based on health claims data, undertreatment of moderate to severe psoriasis appeared to be common.