Cross-cultural adaptation and validation of Injustice Experience Questionnaire in Greek

The Injustice Experience Questionnaire (IEQ) gauges the extent to which individuals with chronic pain perceive feelings of injustice concerning their pain. The study's objective was to assess the feasibility, absolute and relative reliability, as well as the convergent and construct validity of the Greek version of the IEQ.

A cross-cultural adaptation of the IEQ in Greek was carried out according to the published guidelines. Ninety patients with chronic pain and 44 healthy participants completed the IEQ-GR, the Pain Catastrophizing Scale (PCS), and the Hospital Anxiety and Depression Scale (HADS). A subset of 36 volunteers completed the IEQ-GR twice over 1 week.

The ICC was calculated at 0.98 for IEQ-total and 0.83-0.96 for all items. The Cronbach's a was estimated at 0.98 for IEQ-total and 0.91-0.98 for all items. The SEM ranged from 0.20 to 1.63 and the SDC was 0.36-2.62 for all items. Positive and significant correlations between IEQ-GR and PCS (r = 0.59, p < 0.01), HADS (r = 0.58, p < 0.01), HADS depression (r = 0.50, p < 0.01), and HADS anxiety (r = 0.55, p < 0.01), were found. There was a statistically significant difference in IEQ between the patient and control groups.

The IEQ-GR demonstrated excellent reliability, internal consistency, convergent and discriminant validity in a Greek population.