Illness Perception and Cardiovascular Risk Factors in Patients with Type 2 Diabetes: Cross-sectional Questionnaire Study

Aim

To investigate illness perception in patients with type 2 diabetes mellitus and its association with the degree of control over relevant cardiovascular risk factors.

Methods

A cross-sectional questionnaire-based study was performed from June 2007 to March 2008. A stratified random sample of 46 Croatian general practitioners was asked to select, using systematic sampling, the first 6 patients with type 2 diabetes mellitus aged ≥18 years who visited them for consultation during the study period. Data on 250 patients included patient illness perception assessment (Brief Illness Perception Questionnaire, IPQ), cardiovascular risk factors, and socio-demographic data.

Results

The patients’ mean age was 63.0 ± 10.9 years and mean duration of diabetes was 9.3 ± 7.8 years. The patients’ illness perception assessment on an 11-point (0 to 10) scale showed the highest median scores (interquartile range): 10 (8 to 10) for “timeline” and 8 (7 to 9) for “treatment control,” followed by 7 (5 to 8) for “personal control,” 7 (5 to 9) for “understanding,” 5 (3 to 7) for “consequences,” 6 (4 to 7) for “concern,” and 5 (2 to 7) for “emotional response.” The lowest score was 3 (1 to 5) for “identity.” Multivariate logistic regression showed that the Brief IPQ item “concern” (P < 0.001) was a significant predictor of body mass index; “personal control” (P < 0.001) and “concern” (P = 0.048) were significant predictors of fasting blood glucose; “treatment control” (P = 0.009) was a significant predictor of total cholesterol; and “understanding” (P = 0.010) was a significant predictor of blood pressure.

Conclusion

As patients'' beliefs seem to be associated with the degree of control over cardiovascular risk factors, they should be included in routine clinical assessments.Although the quality of guidelines to diabetes care appears to be improved, a poor metabolic control over the illness has been found in as many as 30%-60% of patients with type 2 diabetes treated in routine general practice (GP) settings (1). Despite of the vital role of health care providers, the responsibility for diabetes management largely rests on the patient. Ninety-five percent of health-related decisions are to be made by patients on a daily basis, without even consulting with health care professionals (2,3). These decisions are related to diet, tobacco smoking, foot care, and exercising, adherence to daily urine or blood glucose monitoring, and drug regulation, which should all be harmonized and embedded into working, domestic, and leisure routines. Research has shown the enhancement of active participation and self-care to be the key factor responsible for the improvement of outcomes in diabetic patients (4). Furthermore, there is a growing body of evidence corroborating that the perception of the disease plays an important role in the degree of compliance (5-7).The study on individual perceptions of illness stemmed from the research on health-threat communication (7). Different health behavior theories have been developed to describe individual response to a perceived health threat and the manner of coping with it. One of the widely adopted models is the self-regulation model introduced by Leventhal et al (8,9). The self-regulation model assumes that health-related behavioral patterns are a result of complex multi-faceted representations of illness. Cognitive representation of illness embraces 5 core dimensions (8): identity (ie, label and symptoms that a person ascribes to his or her illness); consequences (ie, expected effects and outcomes of the illness); cause (ie, causal attribution that a patient assigns to his or her illness); timeline (ie, the expected duration of illness viewed from the patient’s perspective); and cure or control modalities (ie, the extent to which a patient believes he/she can recover from the illness or place it under control). Emotional representation also includes negative reactions to the illness, such as fear, anger, and distress. Other studies have provided a quantitative support as to the existence of structural relations between the 5 illness representation components described by Leventhal (8), and to the existence of links between illness perceptions and a number of psychological outcomes, such as coping, mood, functional adaptation, and compliance (9-21).While researchers have often examined the relation of illness perception with psychological outcomes, its relation with cardiovascular risk factors has been studied only on rare occasions (4,22,23). We find this area important, since diabetes and cardiovascular disease often appear as “the two sides of the same coin” (24). Furthermore, in type 2 diabetes, the presence of cardiovascular risk factors at least doubles the risk of cardiovascular death (1). As with most European transitional countries, in Croatia cardiovascular disease is the leading cause of death and accounts for more than half of the overall mortality (25).The aim of this study was to investigate the illness perception in patients with type 2 diabetes and its association with the degree of control over cardiovascular risk factors.