Effect of Psoriatic Arthritis on Treatment Response in Patients With Moderate to Severe Psoriasis

August 2016 | Volume 15 | Issue 8 | Original Article | 917 | Copyright © August 2016

Jacqueline E. Greb BA, Caren Garber BA, and Alice B. Gottlieb MD PhD

Tufts Medical Center, Boston, MA

BACKGROUND: Among patients with moderate-to-severe psoriasis, efficacy, and tolerability of available treatments based on psoriatic arthritis (PsA) history are not well-described.
OBJECTIVE: We evaluate disease characteristics and treatment response variation in the moderate-to-severe psoriasis population based on PsA history.
METHODS: Simple-measure for assessing psoriasis activity (S-MAPA) was used to retrospectively analyze treatment responses.
RESULTS: 191 moderate-to-severe psoriatic patients, 58 with and 133 without rheumatologist-diagnosed PsA were analyzed. Regardless of PsA history, S-MAPA improvement was similar with biologic monotherapy (46.2 versus 44.1; P=0.74), traditional systemic monotherapy (62.29 versus 38.12; P=0.22), and combination treatments (64.62 versus 52.71; P=0.40) after 12 weeks. PsA patients on biologic monotherapy experienced a higher infection rate than patients without PsA (0.57% versus 0.19%; P=0.01). PsA patients experienced more adverse events (AEs) associated with traditional systemic monotherapy than biologic monotherapy (3.25 versus 1.04; P=.001).
LIMITATIONS: The relatively small PsA cohort was the primary limitation.
CONCLUSIONS: Patients with moderate-to-severe psoriasis responded similarly to all treatments independent of PsA history. PsA patients received more overall treatments and more biologic monotherapy prescriptions. PsA patients had a greater infection risk on biologic monotherapy compared to those without PsA, and greater adverse events risk on traditional systemic monotherapy compared to biologic monotherapy.

J Drugs Dermatol. 2016;15(8):917-922.


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



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.