Coronary heart disease (CHD) is a leading cause of illness and death in Western society. The present study was designed to evaluate the utility of illness perceptions and medication beliefs in predicting secondary preventive behaviour among patients with CHD. An extended version of Leventhal's self-regulatory model (SRM) was used as a theoretical framework for this study [Leventhal H, Nerenz DR, Steele DJ. Illness perceptions and coping with health threat. In: Baum A, Taylor SE, Singer JE, editors. Handbook of psychology and health, Volume IV: social psychological aspects of health. Hillsdale (NJ): Erlbaum, 1984. pp. 219-52; Horne R, Weinman J. Self-regulation and self-management in asthma: exploring the role of illness perceptions and treatment beliefs in explaining non-adherence to preventer medication. Psychol Health 2002;17(1):17-32].
Medical and demographic data were gathered from the medical charts of 1611 patients with established CHD from 35 randomly selected general practices. Self-report data about patients' lifestyles (diet, exercise, smoking, alcohol consumption and medication adherence) and information on illness and medication beliefs were provided from postal questionnaire (1084 patients responded; 69% response rate). The relationship between patients' beliefs and their secondary preventive behaviour was examined using regression analyses.
Illness perceptions appeared to be only weak predictors of smoking, exercise, diet, alcohol consumption and medication adherence, accounting for about 2% of the variance in these behaviours. Medication beliefs were moderately related to medication adherence, accounting for about 7% of the variance in scores. A strong belief in the necessity of one's medication and a lower level of concern about one's medication were associated with higher levels of adherence.
An illness perception approach did not prove helpful in predicting secondary preventive behaviour among this group of patients. However, beliefs about medications appear to be reasonable predictive of medication adherence.