Overlapping Comorbidities Observed for Palmoplantar Pustulosis and Psoriasis Vulgaris

Jin Yong Lee, MD, PhD

A cross-sectional study on patients with palmoplantar pustulosis (PPP) found an overlapping comorbidity profile among patients with psoriasis vulgaris.

Despite this, comorbidity risk was believed to be substantially different between these 2 patient groups.

The prevalence of PPP in Western countries is believed to be .01-.05%, and .12% in Asia, with recent research suggesting that systemic involvement plays a role in the pathogenesis of the disease.

Additionally, the suggestion of whether PPP is a variant of psoriasis or a distinct inflammatory disease is unclear and controversial.

In this study, investigators led by Jin Yong Lee, MD, PhD, Seoul National University College of Medicine, assessed the risk of comorbidities in patients with PPP via the Korean National Health Insurance (NHI) database before comparing those patients to those with psoriasis vulgaris and pompholyx.

A pilot study was performed prior to this, with the team comparing patients with PPP to a 1:4 age- and sex-matched general population with data from the NHI Service National Sample Cohort.

From there, they conducted the cross-sectional study using data from the Korean NHI claims databases, which were collected from January 1, 2010- December 31, 2019.

All patients diagnosed with either PPP, psoriasis vulgaris, or pompholyx who visited a dermatologist at this time were enrolled in the study.

The investigators excluded 14,746 patients diagnosed with pompholyx from the PPP group, and 26,151 patients diagnosed with PPP were excluded from the pompholyx group in an effort to minimize misclassification.

From there, 4 categories of combordities were evaluated, including inflammatory arthritis, cardiometabolic diseases, autoimmune diseases, and dermatological diseases.

Patients were identified by a certain disease if they had been diagnosed 3 or more times during physician visits.

In total, 37,399 Korean patients with PPP were included in the study in addition to 332,279 patients with psoriasis vulgaris, and 365, 415 patients with pompholyx.

The mean age for patients with PPP was 48 years, and 51.7% of participants were female. Similarly, the mean age of patients with psoriasis vulgaris was 47.29 (18.34) years and 41.3% were female, and the mean age of patients with pompholyx 40.92 (17.63) years and 57.4% were female.

Investigators observed that patients with PPP had significantly higher risks of developing psoriasis vulgaris than those with pompholyx (P < .001).

Patients with PPP were at a significantly higher risk for psoriatic arthritis, ankylosing spondylitis, type 1 diabetes, type 2 diabetes, Graves disease, Crohn disease, and vitiligo than those with pompholyx following adjustments for demographic covariates.

Furthermore, the risks of ankylosing spondylitis and Graves were significantly higher among patients with PPP vs psoriasis vulgaris.

Notably, the risk of autoimmune diseases was higher in female patients with PPP, with the exception of Crohn disease, as was the risk of cardiometabolic diseases.

“Further studies to explore the pathogenetic mechanisms of these comorbidities and elucidate their associations with PPP are warranted,” the team wrote.

The study, "Risks of Comorbidities in Patients With Palmoplantar Pustulosis vs Patients With Psoriasis Vulgaris or Pompholyx in Korea," was published online in JAMA Dermatology.