Relationships between illness representations, physical activity and depression in Chronic Kidney Disease

Background: Chronic Kidney Disease (CKD) is exacerbated by depression and confers significant healthcare costs. Whilst adverse impacts may be mitigated by physical activity, many patients with CKD remain physically inactive, with this physical inactivity potentially influenced by how CKD is appraised. Objectives: The study aims to explore the relationship between physical activity, depression and illness representations in CKD. Methods: Non-dialysing patients with CKD completed the Revised Illness Perception Questionnaire (IPQ-R), Beck Depression Inventory (BDI-II) and Short-Form International Physical Activity Questionnaire (IPAQ-SF) while demographic information was obtained via medical records. Correlation and 66 regression analyses were conducted to determine the relationship of illness representations with levels of physical activity. Moderation and mediation analyses were performed to investigate the role of depression in any relationship between illness representations and physical activity levels. Results: Seventy respondents, with a mean age of 60 ± 16 years, the majority being male (60%), took part in the study. Of illness representation dimensions, personal control was positively associated with levels of physical activity (r=.288, p<.05) while timeline cyclical was a significant predictor (Beta=-.423, p=.008). Severity of depression was neither a moderator (b= .023, 95% CI [-.015, .061], t=1.201, p=.23) nor a mediator (b=-.021, BCa CI [-.082, .008], p=.33). Conclusions: Facets of illness representations had significant relationships with levels of physical activity. Future research concerning the development and validation of psychological interventions based on an illness representations framework for patients with CKD not on renal-replacement therapy is proposed. The efficacy of such interventions could be then evaluated using a randomised controlled method.