Objectives: To investigate the reliability and validity of the Spanish version of the Fibromyalgia Rapid Screening Tool (FiRST), a brief questionnaire for the detection of fibromyalgia (FM) in patients with diffuse chronic pain seen at primary care health centres.
Methods: The original FiRST French questionnaire was adapted to a Spanish version following the guidelines of the Rheumatology Spanish Society Study Group of FM, and the help provided by professors of French and Spanish Language. In a prospective and multicentre study, patients with chronic pain were initially divided into two groups: a group that included patients that had been diagnosed with FM according to the 1990 ACR criteria and the 2010 ACR preliminary criteria (n=404), and a non-FM (control) group composed of rheumatoid arthritis (RA) (n=147) and osteoarthritis (OA) (n=219) patients. Patients from the FM group were evaluated by assessing tender point assessment, Widespread Pain Index (WPI), Symptom Severity Scale (SSS), FiRST questionnaire and Fibromyalgia Impact Questionnaire (FIQ). The non-FM group was evaluated by means of FiRST, WPI and SSS. Sensitivity, specificity and predictive value as well as the correlation between the global score and other parameters were assessed.
Results: 356 of 404 FM (88.1%) patients who met the 1990 ACR criteria and the ACR 2010 preliminary criteria had a positive FiRST. In the control group (AR plus OA), only 16 (4.4%) subjects had a positive FiRST. The sensitivity value was 92% (95% confidence interval CI: 88.9-95.1), specificity 87.4% (95% CI: 80.8-94.0), positive predictive value 95.7% (95% CI: 93.3-98.1), and negative predictive value 78.2% (95% CI: 70.6-85.9). A significant correlation between the total FiRST score (patients with score 5 or 6) and WPI (p<0.0001), SSS (p<0.0001), time to disease progression (p<0.0001) and FIQ (p<0.0001) was found.
Conclusions: FiRST questionnaire is a useful tool for the detection of FM in primary care health centres.