An exploration of the relationships within and between illness and treatment beliefs in coronary artery disease patients undergoing coronary artery bypass, percutaneous coronary interventions and medical therapy interventions

This study investigated the illness and treatment representations of 214 coronary artery disease patients undergoing medication, percutaneous coronary intervention or coronary artery bypass grafting. Illness representations were investigated using the New Zealand – Illness Perceptions Questionnaire. Results revealed that with these patients, illness representations comprised the components: illness impact, duration, control and self-image. Illness identity was characterised by fatigue, breathlessness and chest-pain; and important perceived causes for their illness were, high cholesterol levels, stress or worry, and eating fatty foods. These belong to a structure of causal beliefs with the components: emotional causes, poor-lifestyle causes and external causes. Treatment beliefs were investigated through the development of a Treatment Representations Inventory which was structured around the four components: treatment value, treatment concerns, decision satisfaction and disease cure. Significant treatment group differences on the sub-scales showed a logical and explainable pattern of group differences, which reflected the treatments’ distinctive and hierarchical natures. The illness cognition scales were employed to systematically develop a path analysis model that represented the multivariate relationships between the components of illness and treatment representations. The final model proved satisfactory across a range of fit indices and elucidated significant and theoretical valid relationships within illness representations components, within treatment representations and between the two types of illness cognition. Additionally, patterns of responses to the illness cognitions were shown to form two distinct clusters of patients. One group appeared to have positive expectations for their illness and treatment, the other a more circumspect and uncertain outlook. A positive outlook led to greater positive affect, serenity, attentiveness and joviality; and less anxiety, depression, hostility and shyness than an uncertain outlook. Over time, and following revascularisation, a number of illness cognitions significantly changed. Patterns of changes differed by treatment group, reflecting the drama involved in treatments undergone and the positive orientation of patients.