Validation of a Spanish version of the Revised Fibromyalgia Impact Questionnaire (FIQR)
BACKGROUND
The Revised version of the Fibromyalgia Impact Questionnaire (FIQR) was published in 2009. The aim of this study was to prepare a Spanish version, and to assess its psychometric properties in a sample of patients with fibromyalgia.


METHODS
The FIQR was translated into Spanish and administered, along with the FIQ, the Hospital Anxiety Depression Scale (HADS), the 36-Item Short-Form Health Survey (SF-36), and the Brief Pain Inventory (BPI), to 113 Spanish fibromyalgia patients. The administration of the Spanish FIQR was repeated a week later.


RESULTS
The Spanish FIQR had high internal consistency (Cronbach’s α was 0.91 and 0.95 at visits 1 and 2 respectively). The test-retest reliability was good for the FIQR total score and its function and symptoms domains (intraclass correlation coefficient (ICC > 0.70), but modest for the overall impact domain (ICC = 0.51). Statistically significant correlations (p < 0.05) were also found between the FIQR and the FIQ scores, as well as between the FIQR scores and the remaining scales’ scores.


CONCLUSIONS
The Spanish version of the FIQR has a good internal consistency and our findings support its validity for assessing fibromyalgia patients. It might be a valid instrument to apply in clinical and investigational grounds.