The pain, depression, disability pathway in those with low back pain: a moderation analysis of health locus of control

Abstract

Low back pain (LBP) is common, impacts on the individual and society, and is a major health concern. Psychological consequences of LBP, such as depression, are significant barriers to recovery, but mechanisms for the development of depression are less well understood. One potential mechanism is the individual’s health locus of control (HLoC), that is, perception of the level of control an individual has over their health. The objective of this study is to investigate the moderation effect of HLoC on the pain–depression–disability pathway in those with LBP. The design is a nested cross-sectional analysis of two existing cohorts of patients (n=637) who had previously consulted their primary care physician about LBP. Measures were taken of HLoC, pain intensity and interference, depression, disability, and bothersomeness. Structural Equation Modeling analysis was applied to two path models that examined the pain to depression to disability pathway moderated by the HLoC constructs of Internality and Externality, respectively. Critical ratio (CR) difference tests were applied to the coefficients using pairwise comparisons. The results show that both models had an acceptable model fit and pathways were significant. CR tests indicated a significant moderation effect, with stronger pathway coefficients for depression for those who report low Internality (β 0.48), compared to those with high Internality (β 0.28). No moderation effects were found within the Externality model. HLoC Internality significantly moderates the pain–depression pathway in those with LBP, meaning that those who have a low perception of control report greater levels of depression. HLoC may signify depression among people with LBP, and could potentially be a target for intervention.

Keywords:

• low back pain
• health locus of control
• moderation
• depression
• disability
• Structural Equation Modeling

Acknowledgments

This research was supported by an Inspire Project Grant to Kate Hope and a Wellcome Trust Fellowship Grant to Professor Kate M Dunn (083572). Interim findings from this project were presented as a poster at the 9th Congress of the European Pain Federation (EFIC) in September 2015 “Structural equation modeling of the moderation effect of health locus of control on the Pain–Depression pathway” (version 1; not peer reviewed). F1000Research 2015, 4:808 (doi: 10.7490/f1000research.1110559.1).

Disclosure

The authors report no conflicts of interest in this work.