Psoriasis and its comorbidities can significantly reduce quality of life and lead to substantial direct and indirect costs for those living with the skin condition. “Determining the prevalence of psoriasis can educate clinicians and patients on populations at greatest risk for the disease,” says April W. Armstrong, MD, MPH. It can also inform health policies on the allocation of healthcare resources and help establish baselines for future studies of patients with psoriasis.

Previous studies on the prevalence of psoriasis in the United States have yielded varying results that are dependent on the population of interest, methodology, and data sourcing. Of note, investigators using databases focusing on urban or commercially insured populations have historically had challenges collecting data from rural and underserved populations. To overcome this issue, the National Health and Nutrition Examination Survey (NHANES) oversamples Black, Hispanic, and low-income White patients to ensure that disease burden is better captured in these populations.

Updating Key Data & Evaluating Changes Over Time

For a study published in JAMA Dermatology, Dr. Armstrong and colleagues sought to determine the prevalence of psoriasis among adults in the US and evaluated prevalence changes since 2003-2004 NHANES data were released. The study aimed to build on recent findings from other research in that it doubled the sample size by combining multiple NHANES cycles, accounted for the overall population as well as demographic subgroups, and better characterized psoriasis severity. According to the study, the prevalence of psoriasis among US adults aged 20 or older was 3.0%, which was 0.2% higher than the 2.8% rate that was seen in recent research. This percentage difference represents approximately 420,000 adult patients with psoriasis. Based on 2020 U.S. Census data, the 3.0% prevalence rate translates to an estimated 7.55 million American adults with psoriasis.

Rates Vary Based on Different Demographics

The study also showed that the prevalence of psoriasis was similar between women and men (3.2% and 2.8%, respectively) and was highest in White people (3.6%), followed by non-Hispanics, including those who are multiracial at 3.1%, Asian individuals at 2.5%, Hispanics (including Mexican Americans and other Hispanics) at 1.9%, and Black people at 1.5%. “Our data suggest that psoriasis remains one of the most common immune-mediated diseases experienced by many adults in the US,” says Dr. Armstrong.

When compared with patients who did not have psoriasis, those with the condition tended to be older. However, prevalence rates varied among those aged 20-59 (Table). For example, the prevalence of psoriasis was 1.6% among people aged 20-29 but 4.3% for those aged 50-59. In addition, the study showed that 21.5% of participants reported having moderate to severe psoriasis.

Implications for Health Policy & Future Efforts

According to the study authors, determining the prevalence of psoriasis has substantial implications. Since primary care clinicians will be the first to encounter patients presenting with psoriasis, efforts are needed to educate them about the various clinical disease presentations. Additionally, since one-third of patients with psoriasis develop psoriatic arthritis, educational initiatives should focus on screening, early recognition, and treatment of psoriatic arthritis and cardiometabolic, hepatic, and mental health comorbidities. Such efforts are concordant with national guideline recommendations.

The new prevalence data can serve as the foundation to better understanding the true burden of psoriasis and raising awareness of associated comorbidities, according to Dr. Armstrong. “These data may help inform future epidemiologic research, clinician and patient education, and health policies that seek to improve the lives of patients with psoriasis,” she says. Future research into the incidence of psoriasis could help clarify differences in temporal trends in its epidemiology. Studies are also warranted to help determine the precise genetic and environmental contributions to the pathogenesis of psoriasis in different racial and ethnic groups.