Validation of the Fibromyalgia Rapid Screening Tool in patients with axial spondyloarthritis: Polish version adaptation and value in clinical practice

Fibromyalgia frequently co‑occurs with axial spondyloarthritis. The Fibromyalgia Rapid Screening Tool (FiRST) is a well‑recognized screening tool for fibromyalgia and has been translated into multiple languages. Yet, it has not been adapted into Polish, nor has it been validated in the context of axial spondyloarthritis. This study aimed to create a Polish version of the FiRST, evaluate its psychometric properties, and conduct its validation among patients with axial spondyloarthritis. We translated and performed a cross‑cultural adaptation of the FiRST into Polish, followed by its validation in a cohort of 174 patients with axial spondyloarthritis. For criterion validity, we employed the 2016 American College of Rheumatology fibromyalgia diagnostic criteria as the gold standard for fibromyalgia diagnosis. The Polish version of the FiRST demonstrated marginally acceptable internal consistency with the Cronbach α coefficient of 0.644, but exhibited high test‑retest reliability, with a global score correlation coefficient of 0.75 (P