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

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.

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.

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).

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.