The objective of this study is to develop and validate a questionnaire for evaluating patients' specific knowledge regarding fibromyalgia. The development of items and questions of the questionnaire was done using four focus group that included physicians, physical therapists, a nurse, and patients with fibromyalgia. Other 30 consecutive patients were recruited to evaluate the questionnaire's reproducibility (intra- and inter-observer). In order to construct validity, the questionnaire was applied to healthcare professionals with knowledge on fibromyalgia and 20 other patients. To investigate sensitivity to change, the questionnaire was applied to 56 patients before and after an educational program (intervention group) or a waiting list (control group). Eighteen questions fulfilled the inclusion criteria and were understandable for more than 90% of the participants. The intraclass correlation coefficients for inter-observer and intra-observer reproducibility ranged from 0.65 to 0.90 and from 0.86 to 0.96, respectively (P < 0.01). For construct validation, healthcare professionals obtained significant higher scores than the patients (P < 0.01). On the sensitivity to change evaluation, the intervention group obtained higher scores than the control group after the educational program (P < 0.01).
The Fibromyalgia Knowledge Questionnaire was developed and it is reliable, valid, and sensitive to changes, for evaluating disease-specific knowledge in patients with fibromyalgia.