Validation of the Simple Psoriatic Arthritis Screening (SiPAS) questionnaire in a Turkish psoriatic population

Objectives: Screening of psoriatic arthritis (PsA) in patients with psoriasis (PsO) is critical for the prevention of irreversible joint erosions, deformity, and disability. The SiPAS questionnaire is a short, simple and useful tool designed to screen PsA. This study aimed to evaluate validity of the SiPAS questionnaire in Turkish patients with PsO.

Materials and methods: The Turkish translation of SiPAS was sent to us by the developer authors of the original index. Subjects were recruited from dermatology outpatient clinics. All patients’ demographic parameters and SiPAS questionnaire results were recorded. After patients completed the questionnaire they were assessed by a rheumatologist according to standard protocol which included a complete history, detailed physical examination, laboratory tests and Classification for Psoriatic Arthritis (CASPAR) criteria. Receiver operating characteristics (ROC) were assessed to obtain sensitivity and specificity of the Turkish version of the SiPAS questionnaire.

Results: One hundred and thirty subjects were recruited into the study. The mean age of subjects were 43.5 years and the 55.4% of subjects were female. Of these, after rheumatologic evaluation 42 patients were diagnosed as PsA. The area under the ROC curve was 0.994 which means as excellent predictor and optimum cut-off threshold to discriminate patients diagnosed with PsA was 3 according to this ROC curve analysis. The overall sensitivity and specificity based on cut-off threshold of 3, were 97.6% and 94.3%, respectively.

Conclusions: The Turkish version of the SiPAS questionnaire is a simple useful, time-saving and valid tool for screening PsA in patients diagnosed with PsO with its high sensitivity and specificity. A SiPAS score ≥3 is an indication for referral to a rheumatologist.

Keywords: CASPAR; SiPAS; psoriasis; psoriatic arthritis; validation.