Psoriasis Severity, Treatment Outcomes Differ Across US Regions

Psoriasis severity and treatment outcomes were found to differ across US geographic regions, in which the East South Central and West South Central regions were associated with the greatest frequencies of very severe disease burden and decreased likelihood of achieving targeted response within 6 months of initiating biologic therapy.

Disease severity and response to therapy among patients with psoriasis may depend on the US geographic region where one resides, according to study findings published in JID Innovations.

In recent decades, research on subpopulations within the United States has identified geographic patterns of disease burden for metabolic diseases such as diabetes and stroke. Similar to these conditions, psoriasis, an immune-mediated, inflammatory disease, is associated with dysmetabolism, but researchers noted that little is known on how psoriatic disease characteristics and treatment outcomes differ geographically in the United States.

“Previously, we have shown that within the Corrona Psoriasis Registry, treatment patterns and baseline disease characteristics of psoriasis also vary among geographic regions within the United States, with more severe disease noted in the South Central Census divisions,” they wrote. “It is currently not known whether treatment outcomes among patients treated for psoriasis with biologics differ between geographic regions of the United States.”

Again leveraging the Corrona Psoriasis Registry, a prospective, multicenter, observational, disease-based registry, the study authors analyzed data of 717 patients with 737 new biologic initiations at or after enrollment in 2018 with a corresponding 6-month follow-up visit.

They examined US geographic variations in disease response to biologic therapy, with outcomes calculated at the 6-month follow-up visit including Psoriasis Area and Severity Index (PASI) 75, 90, and 100; body surface area (BSA) of 1 or lower and 75% improvement in BSA; and clear-to-minimal status for Investigator’s Global Assessment (IGA) of 0 or 1.

Patients were categorized into 7 geographic regions: Northeast (30.3%), East North Central (7.8%), Mountain/West North Central (13.1%), South Atlantic (13.4%), East South Central (14.8%), West South Central (6.7%), and Pacific (13.9%).

Among the study cohort, interleukin (IL)-17 inhibitors were used most frequently (45%), followed by IL-12, IL-23, and IL-23 inhibitors (38%) and tumor necrosis factor (TNF) inhibitors (17%). Half of the patients were obese (body mass index [BMI] > 30), and proportions of patients with obesity and very severe psoriasis (BSA > 20) were greatest in the East South Central and West South Central regions.

At 6 months, 52.2% of all patients achieved PASI 75 and 47.6% reached a treatment target of BSA less than or equal to 1. After adjusting for potential confounders of age, sex, race, BMI, and baseline BSA, several regions were found to be less likely to achieve PASI 75 within 6 months of initiating biologic therapy, compared with patients in the Northeast:

  • East South Central (OR, 0.47; 95% CI, 0.28-0.79; P = .004)
  • West South Central (OR, 0.43; 95% CI, 0.22-0.87; P = .019)
  • Pacific (OR, 0.49; 95% CI, 0.28-0.84; P = .010)

Following these findings, researchers noted the importance of clinicians being aware of the geographic trends in their region, as further understanding of the potential factors driving these regional differences, such as comorbidities and genetic heterogeneity, may help improve treatment algorithms and ultimately advance patient care.


Enos CW, O’Connell KA, Harrison RW, McLean RR, Dube B, Van Voorhees AS. Psoriasis severity, comorbidities, and treatment response differ among geographic regions in the United States. JID Innov. Published online May 5, 2021. doi:10.1016/j.xjidi.2021.100025