Translation and validation of the Norwegian version of the Injustice Experience Questionnaire

Associations between pain intensity, psychosocial factors, and pain-related disability in 4285 patients with chronic pain

Pain, a widespread challenge affecting daily life, is closely linked with psychological and social factors. While pain clearly influences daily function in those affected, the complete extent of its impact is not fully understood. Given the close connection between pain and psychosocial factors, a deeper exploration of these aspects is needed. In this study, we aim to examine the associations between psychosocial factors, pain intensity, and pain-related disability among patients with chronic pain. We used data on 4285 patients from the Oslo University Hospital Pain Registry, and investigated pain-related disability, pain intensity, pain catastrophizing, psychological distress, perceived injustice, insomnia, fatigue, and self-efficacy. We found significant associations between all psychosocial variables and pain-related disability, even after adjusting for demographic factors. In the multiple regression model, sleep problems and pain intensity were identified as primary contributors, alongside psychological distress, and fatigue. Combined, these factors accounted for 26.5% of the variability in pain-related disability, with insomnia and pain intensity exhibiting the strongest associations. While the direction of causation remains unclear, our findings emphasize the potential of interventions aimed at targeting psychosocial factors. Considering the strong link between psychosocial factors and pain-related disability, interventions targeting these factors-particularly insomnia-could reduce disability and enhance quality of life in those who suffer.

Perceived Injustice and Anger in Fibromyalgia With and Without Comorbid Mental Health Conditions: A Hebrew Validation of the Injustice Experience Questionnaire

OBJECTIVES

Perceived injustice (PI), assessed by the Injustice Experience Questionnaire (IEQ), is an important trigger of anger. Both PI and anger are associated with adverse chronic pain outcomes, and with comorbid mental health severity. We aimed examined the roles of PI and anger in mediating pain across Fibromyalgia patients, with and without comorbid anxiety/depression (FM+A/D, FM-A/D, respectively), as well as rheumatoid arthritis (RA), and pain-free controls (PFC). We hypothesized the highest levels of PI, anger, and pain in FM+A/D patients, followed by FM-A/D, RA, and PFC, thus also validating a Hebrew version of the IEQ.

METHODS

We translated the IEQ using the forward-backward method and collected data online. Based on self-reported anxiety/depression, the sample comprised 66 FM+A/D patients, 64 FM-A/D, 34 RA, and 32 PFCs. Assessments included the IEQ, state and trait anger, pain intensity, anxiety, depression, and pain catastrophizing. The structure and reliability of the Hebrew IEQ were examined using factor analysis and Cronbach alpha. Bootstrapped-based modeling was used to test the roles of state and trait anger in mediating and moderating the relationship between PI and pain intensity.

RESULTS

We confirmed a one-factor structure of the IEQ, with excellent reliability. FM+A/D patients demonstrated the highest scores in all measures. Within this group, trait anger moderated the mediating effect of state anger in the relationship between PI and pain intensity.

DISCUSSION

Our findings validate a Hebrew IEQ and highlight the importance of PI and state and trait anger in the differential manifestation of mental health comorbidity in FM.