Abstract
Background
A wide array of measures has been developed to assess the role of psychological factors in the development and persistence of pain. Yet there is likely to be considerable conceptual overlap between such measures, and consequently a lack of clarity about the importance of psychological factors.
Purpose
To investigate whether conceptual overlap exists within psychological measures used in back pain research.
Methods
An observational cohort study of 1591 back pain primary care consulters provided data on anxiety, depression, self-efficacy, coping, illness perceptions, fear avoidance and catastrophising. Exploratory and confirmatory factor analysis (EFA and CFA) was carried out at the sub-scale level (n=20) to investigate factor structure. Derived factors were then tested using hierarchical linear regression in relation to clinical outcomes (pain intensity and disability).
Results
EFA derived 4 factors from the sub-scale measures. Factors were termed ‘distress’ (comprising depression, anxiety, pain self-efficacy, fear avoidance, catastrophising), ‘cognitive’ (cognitive coping strategies), ‘causes’ (psychological, immunity, risk factors) and ‘future’ (expectancies of potential treatment and recovery), and accounted for 65.5% of the data. CFA confirmed the validity of these factors. The distress factor was found to have the strongest association with patients' outcomes, accounting for 28.7% of the variance in pain intensity, and 53.6% in disability.
Conclusion
Considerable overlap exists in psychological measures used in back pain research. Most measures tap in to patients' emotional distress; this factor was shown to have the greatest association with clinical outcomes. These findings have implications for the way psychological measures are used in back pain research.
No conflicts of interest
Source of funding: Programme Grant awarded by the Arthritis Research UK [13413] and Dr KM Dunn's Wellcome Trust Grant [083572].
This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting.
