Japanese version of the early psoriatic arthritis screening questionnaire (EARP).

The early psoriatic arthritis screening questionnaire (EARP) is a simple and fast method for the identification of arthritis in patients with psoriasis. We established the Japanese version of the EARP (J-EARP) questionnaire, which includes 10 items with two choices for each. This study aimed to evaluate the utility of the J-EARP questionnaire. A total of 90 psoriasis patients, 19 psoriatic arthritis (PsA) patients and 71 psoriasis patients without joint involvement, were administered the J-EARP questionnaire. The diagnostic accuracy of the J-EARP questionnaire for the diagnosis of PsA and early-stage PsA was compared by receiver-operator curve (ROC) analysis. The J-EARP questionnaire showed similar ROC characteristics to those of the original version of the EARP (specificity 97.2% and 91.6% and sensitivity 97.2% and 85.2%, respectively) in PsA patients using the cut-off value of 3 for the J-EARP questionnaire, which was the same as that used for the original EARP questionnaire. The scores of the J-EARP questionnaire in early-stage PsA patients (<1 year from onset) were significantly higher than in those of psoriasis patients, but not lower than in those of later stage (≥1 year from onset) PsA patients. The J-EARP questionnaire is simple and fast to administer and has been proven to be robust for the identification of PsA. The J-EARP questionnaire is a useful diagnostic tool for early-stage PsA patients.