INTRODUCTION
Psoriasis is a chronic inflammatory disease that affects an estimated 3% of the population in the United States.1 Psoriasis creates a large economic burden for patients and payers; estimates of the direct costs of psoriasis range from $51.7 billion to $63.2 billion with an additional $23.9 billion
to $35.4 billion from indirect costs.2 Within an environment of ever-growing healthcare costs, the medical cost of psoriasis has increased in recent years, which is in part explained by the introduction of biologic agents.3, 4
Most people with psoriasis have mild disease that can be managed with topical medications.5 Biologic agents are typically
reserved for moderate-to-severe psoriasis.6 To better manage psoriasis treatment costs, it is essential to know which medications are driving the cost of psoriasis management.
The purpose of this study is to determine the most commonly prescribed and most costly drugs used in the treatment of psoriasis, and to test the hypothesis that biologic
agents are responsible for a large portion of the medical cost of psoriasis.
METHODS
Data were collected using the Humana database, a large claims-based database encompassing 18,162,539 patient records.
We searched by ICD-9 code for psoriasis (696.1) and identified psoriasis patients ≤64 years of age who had seen a dermatologist at least once between 2010 and 2014. Patients age 65 and over were excluded because they are likely to have Medicare. From a database of all medications prescribed for psoriasis patients from 2010-2014, we compiled lists of
the 100 drugs most commonly used and the 100 drugs with the highest total cost. We narrowed the list to include drugs whose primary indication is treatment of psoriasis. Generic and brand name drugs with the same formulations were combined.
Percentage of total cost was calculated using the total cost of all psoriasis medications on the list of 100 most costly drugs.
RESULTS
25,986 psoriasis patients in the database were prescribed medications between 2010 and 2014. The drug categories used by psoriasis patients accounting for the most common drugs were antimicrobials, psoriasis treatments, psychiatric drugs, and analgesics (Table I). We identified 18 medications with a primary indication for psoriasis treatment; there were 16 drugs after combining generic and brand name formulations (Table II). Biologic agents were used by 9.6% of psoriasis patients; two biologic drugs (adalimumab and etanercept) appeared on the list of common medications. The five most commonly used drugs were topical corticosteroids and vitamin D analogues. Topical treatments were prescribed much more frequently than any other treatment modality (Figure 1).
The drug categories used by psoriasis patients accounting for the most cost were for psoriasis, diabetes, and psychiatric disorders.
Of these most costly medications, we identified 27 drugs with a primary indication for psoriasis treatment; there were 18 drugs after combining generic and brand name formulations (Table
IV). The three most costly drugs were biologic agents, which altogether made up 86% of the total cost (Figure 2).
