Background/Purpose: Obesity is more prevalent among patients
with psoriasis and psoriatic arthritis (PsA). This correlation appears to be related
to fat tissue-driven systemic inflammation. Although bariatric surgery has been
shown to improve several obesity-related comorbidities, the effects of surgical
weight loss on psoriasis and PsA are unknown. Our objective was to investigate
the effects of weight loss from bariatric surgery on psoriasis and PsA.

Methods:
A retrospective database of 9,073 bariatric surgeries performed at a single
center between 2002-2013 was queried. Patients with a diagnosis of psoriasis
prior to surgery were identified. Patients were contacted about their history
of psoriasis, PsA, change in symptoms, and treatment modalities pre- and
postoperatively. The primary outcome was the percentage of patients who
reported improvement (reduction of >5 on rating scale 0-10) in psoriasis and
PsA after surgery. Secondary analyses were performed to define factors
associated with improvement in psoriasis and PsA.

Results:
We identified 128 patients with a preoperative diagnosis of psoriasis.
Eighty-six (67%) patients completed the study. Baseline patient characteristics
are listed in Table 1. The mean time from surgery was 6.1 years, with a mean excess
weight loss (EWL) of 46.2%. Twenty-one (24%) patients with psoriasis also had a
preoperative diagnosis of PsA

At the
time of contact, 55% of psoriasis and 62% of PsA patients reported subjective
improvement of their disease. Disease severity rating (0-10 scale) significantly
decreased from prior to surgery compared to 1 year post surgery for psoriasis (5.6
vs 4.4, p<0.01) and PsA (6.4 vs 4.5, p=0.01), and was more pronounced among
severe (rating >5) psoriasis (7.7 vs 5.7, p<0.01) and PsA (8.2 vs 4.8,
p<0.01).

In
secondary analyses of patients with severe psoriasis and PsA, higher EWL at recent
follow-up was significantly associated with improvement in psoriasis (59.5 vs
43.5%, p=0.046) and higher EWL at 1 year was associated with a trend in PsA improvement
(55.4 vs 43.8%, p=0.47). Improvement in disease among severe psoriasis patients
was associated with higher rating of disease at the time of surgery (8.9 vs
7.4, p<0.01) and older age at diagnosis (37 vs 26yr, p=0.02).

Conclusion:
Although the natural history of psoriasis and PsA is typically chronic, a majority
of patients experience improvement after bariatric surgery. Our results
indicate an association between EWL and symptomatic improvement in severe cases
of psoriasis. Factors such as older age at diagnosis of psoriasis and severity
of psoriasis may be used to identify patients with a greater likelihood of
improvement. Despite study limitations, we show for the first time an improvement
in PsA after bariatric surgery and a possible association with surgical EWL. Larger
prospective studies are needed to further define the true effect of surgical
weight loss on psoriasis and PsA.

SD Standard Deviation; n= number of psoriasis
patients