BACKGROUND
Psoriasis is a chronic, immune-mediated disorder affecting
2-3% of the global population and is most often
characterized by erythematous, indurated, and scaly
plaques. In addition to its cutaneous manifestations, psoriasis
negatively impacts quality of life, and is associated with multiple
comorbidities including arthritis. Up to 40% of patients
with psoriasis develop psoriatic arthritis (PsA) characterized
by an inflammatory, destructive arthritis, which can lead to
permanent joint deformities, particularly when left untreated.1
PsA hallmarks include enthesitis, dactylitis, spondylitis, and
nail dystrophy and is associated with significant morbidity
and decreased quality of life.2 Baseline skin disease severity
as well as treatment response among psoriasis patients with
moderate-to-severe cutaneous involvement with or without
PsA has not been thoroughly investigated. The purpose of this
study is to evaluate disease characteristics and variations in
treatment response in the moderate-to-severe psoriasis population
based on the presence or absence of PsA in order to
guide treatment decisions
METHODS
Demographics
A database of psoriatic patient visits to the Department of Dermatology
at Tufts Medical Center was analyzed in a retrospective,
cross-sectional study. Tufts Medical Center, a tertiary care center
in Boston, Massachusetts, accepts a significant number
of referrals from the surrounding community, and sees 3,600
new patients and 19,000 total psoriasis visits yearly. The present
analysis included visits for patients with moderate-to-severe
psoriasis between January 1, 2008 and March 1, 2015 excluding
those between January 12, 2012 and July 9, 2012 during the
transition to electronic medical record. Patients of all ages were
included. Codes for psoriasis (ICD-9 696.1) and PsA (ICD-9 696.0)
were used to identify appropriate visits. All psoriasis cases were
diagnosed by a dermatologist, while PsA cases were diagnosed
by a rheumatologist.
Treatment Courses
Treatment courses for moderate-to-severe, plaque-type psoriasis
were included as defined by Physician Global Assessment
(PGA) of 3 or greater and simple-measure for assessing psoriasis
activity (S-MAPA) [physician global assessment (PGA) x
body surface area (BSA)] greater than or equal to 15 at some
point during or before the treatment course.3 All treatment
courses were greater than or equal to eight weeks long and
composed of at least two documented clinic visits. Continuity
was assumed between visits until a treatment was described as
discontinued in the patient’s chart.