Development and validation of the Fibromyalgia Rapid Screening Tool (FiRST)

The goal of this study was to develop and validate a self-completed questionnaire, the Fibromyalgia Rapid Screening Tool (FiRST), for the detection of fibromyalgia syndrome in patients with diffuse chronic pain. Items requiring "yes/no" responses and relating to the most relevant clinical characteristics of fibromyalgia were compiled by a group of rheumatologists and pain experts. The provisional questionnaire was tested in a prospective multicenter study of 162 patients with chronic pain due to fibromyalgia (according to ACR criteria) (n=92) compared with a group of patients with chronic diffuse pain due to other rheumatic conditions, including rheumatoid arthritis (n=32), ankylosing spondylitis (n=25) and osteoarthritis (n=13). Identification of the most discriminant combinations of items for fibromyalgia and the calculation of their sensitivity and specificity were based on both univariate and multivariate (stepwise logistic regression) analyses. The assessment of the psychometric properties of the questionnaire also dealt with face validity, content validity, test-retest reliability and convergent/divergent validity. Based on univariate and multivariate analyses, we retained only six items in the final version of FiRST. These items were used to calculate the sensitivity, specificity and predictive accuracy of the questionnaire. A cut-off score of 5 (corresponding to the number of positive items) gave the highest rate of correct identification of patients (87.9%), with a sensitivity of 90.5% and a specificity of 85.7%. In conclusion, FiRST is a brief, simple and straightforward self-administered questionnaire with excellent discriminative value, of potential value for the detection of fibromyalgia in both daily practice and clinical research.