Dimensionality, Reliability, and Validity of the Revised Fibromyalgia Impact Questionnaire in Two Spanish Samples

Abstract

Objective. The present study attempted to fill a research gap by performing the first dimensionality analysis of the Revised Fibromyalgia Impact Questionnaire (FIQR) using exploratory and confirmatory techniques. A second objective was to report on the reliability and construct validity of the FIQR in Spanish patients. Methods. FIQR data from a sample of adult fibromyalgia patients (n ‫؍‬ 113) were analyzed using principal components analysis (PCA). Subsequently, a set of confirmatory factor analyses (CFAs) was conducted in another sample (n ‫؍‬ 179) to analyze the goodness of fit of various factor models. FIQR reliability was assessed by computing Cronbach's alpha and coefficient H. Construct validity was evaluated by comparing the FIQR scores of participants categorized by employment status. Results. According to the PCA, the FIQR structure might be described as having 1 global factor of functional impairment. Although subsequent CFAs confirmed that 1 factor accounted for the greatest proportion of common variance in the FIQR items, a confirmatory bifactor analysis indicated that the items were multidimensional because of their simultaneous significant loading on specific factors. The Cronbach's alpha values of the FIQR domains were very good (>0.80) and the H estimate for the FIQR total score was excellent (0.93). Overall, the FIQR domains were able to distinguish between patients differing in employment status (working outside the home versus on sick leave). Conclusion. Our results indicate that the Spanish version of the FIQR has a complex factor structure, has excellent reliability, and shows good construct validity.

Association of the Weekly Practice of Guided Physical Activity With the Reduction of Falls and Symptoms of Fibromyalgia in Adult Women

“…The FIQ-R is considered the gold standard instrument for assessing physical function, patient global improvement, and multidimensional function (21). It consists of 21 separate questions based on an 11-point numeric rating scale of 0-10, with 10 denoting the worst conditions.…”

The effectiveness of the Mitchell Method Relaxation Technique for the treatment of fibromyalgia symptoms: A three-arm randomized controlled trial.

“…The FIQR is an advanced measurement in comparison to FIQ (Burckhardt, Clark, & Bennett, 1991), as it includes symptoms of tenderness and dyscognition and does not have sex or race biased items. The FIQR has desirable discriminant validity (Luciano, Aguado, & Seranno-Blanco, 2013). The Cronbach's α value of the FIQR domains was higher than 0.80 (Bennet et al, 2009).…”

Interdisciplinary Treatment of Patients with Fibromyalgia: Improvement of Their Health‐Related Quality of Life

“…Such interventions may be more successful earlier in the course of illness, at the beginning of the symptoms . For future research it would be suggested to use the FIQ‐Revised as it may be more sensitive to change that the original version and reports about physical data would be useful. It would also be important to use the more recent ACR criteria for FM .…”