Reliability and validity of the Persian version of psoriatic arthritis screening questionnaire

Background: The Early Arthritis for Psoriatic Patients (EARP) questionnaire is a fast and simple way to screen psoriatic arthritis. This study was carried out to investigate the diagnostic accuracy of the Persian version of the Early Arthritis for Psoriatic Patients (P-EARP) questionnaire.

Methods: A total of 100 psoriasis patients responded to the questionnaire after the translation procedure (translation, back translation). After determining the validity of the questionnaire, the diagnostic accuracy of the P-EARP questionnaire was assessed using the ROC curve (receiver operating characteristic curve). Internal and external reliability of the questionnaire were also evaluated by statistical tests.

Results: In assessing the reliability of the questionnaire using test-retest, correlation coefficient (r=0.994, p <0.001) and Cronbach's alpha (α = 0.85) were obtained. The P-EARP questionnaire had a sensitivity and specificity of 90.48% and 96.55% in ROC analysis, respectively, and cutoff point 3 was regarded as the cutoff point of the P-EARP questionnaire like the original version of the questionnaire (EARP).

Conclusion: The results of this study showed that the P-EARP questionnaire had high sensitivity and specificity for the identification of psoriatic arthritis. The P-EARP questionnaire is an appropriate screening tool for the identification of psoriatic arthritis in the dermatology clinics.