# Psoriasis outcomes following metabolic bariatric surgery - a systematic review of the literature

## TL;DR

This review finds that metabolic bariatric surgery may improve psoriasis symptoms, especially with gastric bypass, but more research is needed to guide treatment decisions.

## Contribution

The study systematically reviews evidence on psoriasis outcomes after metabolic bariatric surgery and identifies factors influencing clinical response.

## Key findings

- Psoriasis severity and treatment requirements decreased significantly after metabolic bariatric surgery.
- Gastric bypass was associated with greater improvement in psoriasis compared to non-bypass procedures.
- Greater weight loss and older age were linked to better psoriasis outcomes.

## Abstract

Metabolic bariatric surgery (MBS) has been associated with improved clinical outcomes of psoriasis, yet evidence-based guidelines remain unclear. This systematic review aims to analyze current evidence on psoriasis outcomes following MBS and identify factors influencing clinical response.

A systematic literature search of PubMed®, Scopus, and Google Scholar® was conducted according to PRISMA guidelines. Data extracted included study design, patient demographics, type of MBS, weight loss, and psoriasis outcomes assessed by Psoriasis Area Severity Index (PASI), percentage of affected body surface area (%ABSA), nail involvement, Dermatology Life Quality Index (DLQI), and treatment requirements. Subgroup analysis compared gastric bypass with non-bypass procedures. Due to heterogeneity, a qualitative synthesis was performed.

Six studies involving 447 patients were included. Demographic data were available for 159 patients (mean age 46.9 years, mean BMI 43.8 kg/m²). Pooled BMI reduction was 11.0 ± 3.3 kg/m². Baseline therapies included systemic in 53%, topical in 44%, and phototherapy in 5%. After surgery, systemic therapy decreased to 34%, topical to 39%, and 29% required no treatment. DLQI decreased from 14.9 to 5.0, %ABSA from 5.7 to 1.7, PASI from 3.6 to 1.2, and nail involvement from 43.8% to 21.9% (p < 0.05). Overall, 69.5% of individuals demonstrated improvement or remission of psoriasis, primarily defined by reduced or discontinued treatment. Improvement or remission was noted in 80% of gastric bypass and 10% after non-bypass surgery, with higher PASI reduction after bypass (ΔPASI 2.32 vs 1.67). Factors related to improved clinical response included greater excess weight loss, older age, Roux-en-Y gastric bypass and absence of family history of psoriasis.

MBS may improve psoriasis severity, quality of life, and treatment requirements, but current evidence is uncertain. Weight loss magnitude, type of MBS and patient characteristics might affect clinical response of psoriasis. Further prospective studies are required to establish personalized management among individuals with psoriasis and obesity.

Registration of systematic review: PROSPERO database (UIN: CRD420251108229)