The prevalence of previously diagnosed and undiagnosed psoriasis in US adults: results from NHANES 2003-2004.
BACKGROUND
Psoriasis is a predictor of morbidity. It is important to determine the extent to which psoriasis remains undiagnosed.


OBJECTIVE
To determine the prevalence of psoriasis.


METHODS
We conducted a cross-sectional study using the National Health and Nutrition Examination Survey 2003-2004.


RESULTS
The prevalence of diagnosed psoriasis was 3.15% (95% confidence interval [CI], 2.18-4.53), corresponding to 5 million adults. Approximately 17% of these patients have moderate to severe psoriasis based on body surface area report and 25% rate psoriasis a large problem in everyday life. The prevalence of undiagnosed active psoriasis by conservative estimate was 0.4% (95% CI, 0.19-0.82), corresponding to approximately 600,000 US adults, and 2.28% (95% CI, 1.47-3.50) by a broader definition, corresponding to 3.6 million US adults. Undiagnosed patients had a trend toward being more likely to be male, nonwhite, less educated, and unmarried compared with patients who had received a diagnosis.


CONCLUSIONS
The method for determining the presence of psoriasis had limited ability to detect mild disease and only fair interrater agreement.


CONCLUSIONS
More than 5 million adults have been diagnosed with psoriasis. A large number have undiagnosed psoriasis and there are important disparities which may be associated with not receiving medical attention.
Kurd
Shanu Kohli
SK
Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Gelfand
Joel M
JM
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D011565:Psoriasis / Q000175:diagnosis* / Q000453:epidemiology*; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology