Background/Purpose:  Several questionnaires have been developed to help identify psoriatic arthritis (PsA) among patients with psoriasis (PsO), but there is no screening tool yet tested through joint efforts by Dermatologists and Rheumatologists in Korea. The PsO Epidemiology Screening Test (PEST) is a simple self-administered questionnaire which has been validated in western countries. Our study aimed to investigate the utility and validation of PEST for screening PsA in Korean PsO patients.

Methods:  The PEST, consisted of 5 questions, was translated into Korean and then back-translated to English for comparison. This form was tested on PsO patients visiting the Dermatology clinic at 5 hospitals in urban areas. Patients who checked ‘yes’ to 2 or more questions were referred to Rheumatology for further evaluation. Patients meeting the classification criteria for psoriatic arthritis (CASPAR) criteria were confirmed to have PsA.

Results:  A total of 191 PsO patients from 5 centers were enrolled. The mean age was 45.1 years, and male/female ratio was 1.27. Of these, 150 patients checked ‘yes’ to 0 or 1 question of PEST questionnaire. Among the 41 patients with PEST ≥ 2, 35 patients were eventually assessed by a Rheumatologist. Of these subjects, 17 (48.6%) patients were finally diagnosed as PsA. Compared with PsO only patients, PsA patients had higher rate of female and lower rate of phototherapy history, although statistically insignificant. When comparing the characteristics between PsA and non-PsA among the patients assessed by rheumatologist, patients with PsA showed higher patient’s global assessment, physician’s global assessment, and Routine Assessments of Patient Index Data 3 (RAPID3) score than those without PsA. Six patients of the 17 PsA patients (35.3%) had radiographic evidence of sacroilitis. Among PsA patients, the proportion of patients with PEST score of 2 was 47% (8/17). The overall specificity of PEST at a cut-point of 2 was 89.3%. Using the known PEST cut-off score of 3, its specificity increased to 94.0%, but sensitivity dropped to 52.9%.

Conclusion:  This study supports that the Korean version of PEST is a convenient tool for screening PsA, and the PEST score of 2 points would be a favorable cut-off value for screening Korean PsO patients. However, its performance and utility in our region need to be further investigated.

• References

1. Ibrahim GH, Buch MH, Lawson C, Waxman R, Helliwell PS. Evaluation of an existing screening tool for psoriatic arthritis in people with psoriasis and the development of a new instrument: the Psoriasis Epidemiology Screening Tool (PEST) questionnaire. Clin Exp Rheumatol. 2009;27:469-74

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/utilization-of-the-psoriasis-epidemiology-screening-tool-pest-questionnaire-to-detect-psoriatic-arthritis-in-clinical-practice-data-from-the-validation-of-psoriatic-arthritis-screening-tool-for-kor/