Psoriasis Treatment Patterns: A Retrospective Claims Study

Thesis (Master's)--University of Washington, 2018BACKGROUND: Psoriasis (PsO) is a chronic, autoimmune, dermatologic disease affecting 7.5 million adults in the United States. Treatment options for psoriasis include topical therapy, phototherapy, oral systemic therapies, and biologics. Currently, there is a gap in the evidence in the evaluation of treatment patterns for psoriasis. With emerging options in managing psoriasis, it has become increasingly important to investigate current utilization patterns. METHODS: This observational, retrospective cohort study utilized the MarketScan® Commercial Claims and Medicare Supplemental Databases from January 1st, 2014 to December 31st, 2016. The target population was psoriasis patients over 18 years old who were new users of oral or biologic psoriasis medications. Descriptive statistics including proportions of patients on each treatment type were presented. Outcomes of interest were persistence, switching, and restarting. We investigated within-class persistence, between-class switching and between-class restarting. Additionally, we compared orals and biologics with respect to persistence and switching. Lines of therapy and temporal patterns of switching and restarting after loss of persistence were also characterized. Furthermore, a Cox regression model was used to compare persistence on orals and biologics as overall classes. RESULTS: A total of 5933 patients were identified. 2600 patients lost persistence on their index medication class. Patients whose index drug was a Vitamin A derivative or other biologic had highest proportions of loss of persistence. Treatment type (oral versus biologic) had no bearing on persistence (HR: 1.00, 95%CI: 0.93, 1.09). Of the 2600 patients who lost persistence, 546 switched classes at least once during the study period. The most common switch from an oral index therapy was to a TNF-α inhibitor. The most common switch from a biologic was to a PDE4 inhibitor. A second switch was fairly uncommon, with 93 of 546 patients undergoing a second switch. Of 2600 patients who lost persistence, 1853 patients restarted their index medication class. The most commonly restarted oral medication class was PDE4 inhibitors (27.5% of all restarts), followed by folic acid antagonists (19.9%). TNF-α inhibitors were more frequently restarted than other biologics (32.2% versus 18.1% of all restarts). CONCLUSION: Approximately half of all patients lost persistence, after which the majority restarted their index drug. More switches from orals to biologics were made than vice versa, with larger proportions of biologics constituting 2nd line treatment compared to 1st line treatment. More studies are needed to identify characteristics of patients that differentiate patterns of treatment utilization in US adult psoriasis patients