Geographic Variation in Psoriasis Care: Epidemiology, Access, and Prescribing Behavior

Regional variation in psoriasis patient characteristics and treatment patterns is a multifactorial phenomenon that reflects both true epidemiologic differences and structural disparities in access to care. Real-world analyses reveal meaningful geographic heterogeneity across the United States, with distinct clinical profiles observed in regions such as the South Atlantic and East South Central—differences that encompass comorbidity burden, prevalence of psoriatic arthritis, and baseline disease severity.

Interpreting these differences requires awareness of several potential confounders. Large academic or specialty-focused sites within certain regions may recruit distinct patient populations, skewing the apparent demographics of disease in those areas. Additionally, the practice of "buy and bill"—in which providers purchase and administer biologics directly—can significantly influence prescribing patterns, particularly for agents like tildrakizumab, where this reimbursement model is more commonly used.

Insurance coverage and formulary access are perhaps the most powerful drivers of geographic prescribing variation. Each state Medicaid program maintains its own formulary, and private carriers have regional footprints that vary substantially. These structural factors can determine which biologics are accessible in a given region, often as much as or more than clinical preference.

Beyond coverage, patient-level factors such as socioeconomic status, age distribution, and local care infrastructure contribute to the geographic variation observed. Recognizing these dynamics is essential for clinicians and health system planners seeking to reduce disparities, improve formulary design, and ensure that all patients with psoriasis have equitable access to the treatments best suited to their clinical profile.

Reference:

Prajapati VH, Blachley T, Eliot M, et al. Regional differences in patient characteristics among US biologic initiators from the PPD CorEvitas Psoriasis Registry. Poster presented at: Winter Clinical Dermatology Conference; January 16-21, 2026; Maui, Hawaii.