Background: Psoriasis is a chronic dermatological illness with a high burden of morbidity. There is no collective data on its prevalence and incidence in Thailand to date.

Objective: To explore the prevalence and patient characteristics in a primary care area with a population of approximately 30,000 under the Universal Health Care Coverage Scheme serviced by the authors’ university hospital.

Materials and Methods: The authors conducted a retrospective database analysis from the hospital electronic medical record system on patients seen between January 2015 and December 2019. Psoriasis patients were identified by using the International Statistical Classification of Diseases and Related Health Problems Tenth Revision codes containing L40 (L40.0 to L40.9). The diagnosis for each patient was then confirmed from the medical chart review. The number of visits and number of psoriasis patients in the Universal Health Care Coverage Scheme in the primary care setting was counted, and a five-year period prevalence was calculated. Characteristics of psoriasis patients were analyzed including their ages, gender, comorbidity, and systemic treatment received.

Results: During the five-year period, there were 338 visits from 40 individual psoriasis patients. The five-year period prevalence of psoriasis was 0.13% or 133 per 100,000 persons. The mean age of psoriasis patients was 50 years. Male consisted of 47% of patients. Forty-two percent of patients required systemic treatment.

Conclusion: The five-year period prevalence of psoriasis was 0.13%, which is less than the prevalence in the western countries but similar to other east Asian countries. The limitation of the present study was the relatively small geographic area and the possibility of underestimating prevalence due to some patients may not have sought treatment or were treated at other health facilities. After adjusting for underreporting bias, the adjusted prevalence is 0.43%.

Keywords: Psoriasis, Prevalence, Thailand

DOI: doi.org/10.35755/jmedassocthai.2021.04.11913

Received 15 September 2020 | Revised 24 November 2020 | Accepted 3 December 2020