No Link Observed Between Gastrointestinal Tract Surgery and New Psoriasis

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Both gastrointestinal surgery and appendectomies were not associated with any increased risk of psoriasis development in a national cohort.

Despite a risk of disruption to the microbiome, gastrointestinal tract surgeries are associated with minimal risk of developing psoriasis.1

In new retrospective analysis data from a group of Taiwan investigators, invasive gastrointestinal tract procedures including appendectomy were not significantly associated with increased risk of a new psoriasis diagnosis. The findings additionally elucidated age- and sex-specific risk of new psoriasis diagnoses among such patients.

Led by Dr. Yi-Huei Liu, of the Chung Shan Medical University in Taichung, investigators sought to examine the link between gastrointestinal tract surgery and newly diagnosed psoriasis. Non-genetic psoriasis etiology is not absolutely understood by clinicians, though previous research has pointed to triggers including “skin micro-trauma” as a potential risk factor for the chronic skin disease.

What’s more, the gut microbiome is a pivotal factor in immune regulation. In a recent interview with HCPLive, dermatologist Karan Lal, DO, MS, described a complex dynamic between chronic skin diseases and microbiota.2

“We know that with psoriasis, if they have a leaky gut, they have association with inflammatory bowel disease and a lot of gut issues,” Lal said. “And so maybe that's why people translate that into the ‘skin microbiome.’ But again, that's a lot of the people who don't really understand the true relationship with the skin gut axis.”

Nonetheless, Liu and colleagues stressed the little-defined association between these potential risk factors and newly diagnosed psoriasis.

“Even if surgeries are widely considered a risk factor and disrupt the microbiome in the gastrointestinal tract, resulting in psoriasis, no previous studies have investigated the epidemiological relationship between gastrointestinal tract surgeries and subsequent pathogenesis of psoriasis,” they wrote. “Therefore, we conducted a nationwide case-control study to explore this issue.”

Investigators conducted a nested case-control analysis using data from the Taiwan National Health Insurance Research Database, including patients with newly diagnosed psoriasis from 2005 – 2013. Their retrospective analysis spanned 5 years after the index date of first psoriasis diagnosis. A control cohort of patients who had never been diagnosed with psoriasis or a similar disorder was matched 2:1 by age and sex to compare the association of concurrent gastrointestinal tract surgery.

The final assessment included 16,655 patients with newly diagnosed psoriasis from 2005 – 2013. Mean age of both cohorts was 32.2 years old. Chronic diseases including hypertension, diabetes, COPD, and hepatitis C were significantly more prevalent in patients with newly diagnosed psoriasis.

Liu and colleagues’ conditional logistic regression showed an 8% decreased risk of newly diagnosed psoriasis among patients who underwent gastrointestinal tract surgery (condition odds ratio [cOR], 0.92; 95% CI, 0.76 – 1.12; P = .426), and a 2% decreased risk of psoriasis among patients who underwent appendectomy (cOR, 0.98; 95% CI, 0.76 – 1.27; P = .896).

In the multivariate regression analysis of age- and sex-related factors, investigators observed only patients aged 20 – 39 were at an increased risk of newly diagnosed psoriasis following gastrointestinal tract surgery (OR, 1.09; 95% CI, 0.79 – 1.51; P = .58), though the association was insignificant. Both male (OR, 0.96; 95%, 0.71 – 1.29; P = .762) and female (OR, 0.90; 95% CI, 0.69 – 1.17; P = .427) patients were at an insignificantly decreased risk of newly diagnosed psoriasis after surgery.

Regarding appendectomy, each of patients aged <20 years, 20 – 39 years, and 40 – 59 years were at an insignificantly increased risk of newly diagnosed psoriasis after procedure, as well as both female and male patients.

“In conclusion, our study shows that gastrointestinal surgeries have a limited effect on psoriasis,” investigators wrote. “Except for gastrointestinal tract surgery, appendectomy did not have significant age- or sex-related effects on psoriasis.”

However, the team stressed that their provisional data based solely on the Taiwan population would require further analysis of additional ethnicities and populations to interpret associations between surgery and psoriasis.


  1. Liu YH, Zhuo XJ, Hung YM, Wang YH, Chang R, Wei JC. Absence of an association between gastrointestinal tract surgery and newly diagnosed psoriasis: A nationwide, population-based, nested, case-control study [published online ahead of print, 2023 May 24]. Int J Rheum Dis. 2023;10.1111/1756-185X.14750. doi:10.1111/1756-185X.14750
  2. Smith T. Karan Lal, DO: Relationship Between Psoriasis and the Skin, Gut Microbiome. HCPLive. Published December 6, 2022. Accessed May 29, 2023.