Exploring the factorial structure of the revised Fibromyalgia Impact Questionnaire (FIQR) in a Portuguese sample of fibromyalgia patients

IntroductionThe Revised-Fibromyalgia Impact Questionnaire (FIQR), composed by 21 items, is one of the most used tools to measure the impact of fibromyalgia both in clinical and research settings. Although it has demonstrated good psychometric properties (Bennet et al., 2009; Costa et al., 2015), little is known about its factorial structure.Objective/AimsTo explore FIQR's factorial structure and examine its association with several psychological constructs.MethodsHundred and three women with fibromyalgia (mean age 47.32 ± 10.63) filled in the Portuguese validated versions of the FIQR, Perceived Stress Scale, Perseverative Thinking Questionnaire, Beck Depression Inventory-II and Profile of Mood States. A principal components analysis with varimax rotation was carried out. The number of factors to extract was based on Cattel's scree plot and eigenvalues’ magnitude. The associations between FIQR dimensions and psychological constructs were examined via Pearson correlations and multiple linear regressions.ResultsThree factors were extracted [F1/Function = Items 1–9, α = 0.92; F2/Symptoms = Items 12, 16–21, α = 0.83; F3/Impact = Items 10, 11, 13–15, α = 0.83] explaining 58.57% of the variance. FIQR symptoms were the best and, nearly in all analyses, the only significant predictor.ConclusionsThe factorial structure of the Portuguese version of FIQR partially overlaps with the proposed theoretical domains (Bennet et al., 2009). Similarly to Luciano et al.’s study (2013), factorial analysis also evidenced the multidimensionality of some items. Fibromyalgia symptoms seem to play the most deleterious effect, being associated with poor mental health indicators. Future studies are needed to confirm the factorial structure found, due to sample size, items subjectivity and study's exploratory nature.Disclosure of interestThe authors have not supplied their declaration of competing interest.