Evaluating the Effect of Treatment Persistence on the Economic Burden of Moderate to Severe Psoriasis and/or Psoriatic Arthritis Patients in the US Department of Defense Population

BACKGROUND: Psoriasis is a chronic, hyper-proliferative dermatological condition associated with joint symptoms known as psoriatic arthritis (PsA). In a 2013 review, the total economic burden of PsA was estimated at $51.7-$63.2 billion. The economic burden of moderate to severe psoriasis patients has reduced significantly with the advent of biologies, but there remains a dearth of real-world evidence of the impact of treatment persistence on the economic burden of moderate to severe psoriasis and/or PsA patients. OBJECTIVE: To evaluate the overall and psoriasis and/or PsA-related health care utilization and costs among patients who were persistent versus those nonpersistent on index biologic among the moderate to severe psoriasis and/or PsA population. METHODS: Adult patients with >= 2 claims with diagnosis of psoriasis and/or PsA during the period of November 2010-0ctober 2015 were identified from the U.S. Department of Defense database; the first diagnosis date during November 2011-October 2014 was defined as the index date. As of the index date, patients were considered to have moderate to severe psoriasis or PsA if they had >= 1 nontopical systemic therapy or phototherapy during the 1-year pre- or 1-month post-index date. Persistence to index therapy, defined as the first biologic used (etanercept, adalimumab, ustekinumab, infliximab) on or within 30 days post-index date, was determined based on the biologic dosing schedule and a 90-day gap. Generalized linear models were used to compare the health care utilization and costs between persistent and nonpersistent patients during the 1-year post-index period. RESULTS: A total of 2,945 moderate to severe psoriasis and/or PsA patients were identified. Of those, 1,899 (64.5%) were persistent and 1,046 (35.5%) were nonpersistent. Compared with nonpersistent patients, persistent patients were older (49.2 vs. 45.5 years; P<0.001) and more likely to be male (52% vs. 45%; P<0.001). More persistent patients were diagnosed with dyslipidemia (40% vs. 35%; P=0.002), had lower antidepressant use (23.4% vs. 27.4%; P<0.001), and had lower anxiolytic use (30% vs. 37%; P<0.001) compared with nonpersistent patients. After adjusting for demographic and clinical characteristics, nonpersistent patients had higher total medical costs ($12,457 vs. $8,964; P<0.001) compared with persistent patients, and ambulatory visits (23.9 vs. 21.4; P=0.007) were a major contributor. Approximately 40% of the total overall medical costs were attributed to psoriasis and PsA, Although persistent patients incurred higher pharmacy costs ($10,684 vs. $7,849; P<0.001) due to higher biologic use and the potentially high per-unit cost of biologies, their psoriasis- and/or PsA-related medical costs were significantly lower than those of nonpersistent patients ($3,395 vs. $5,041; P<0.001). Total overall costs combining CONCLUSIONS: Moderate to severe psoriasis and/or PsA patients who were persistent on index biologic treatment had higher pharmacy utilization and costs, albeit with lower medical costs and similar total costs, compared with nonpersistent patients. Copyright (C) 2018, Academy of Managed Care Pharmacy. All rights reserved.