PREVIOUS STUDIES OF PSYCHOLOGICAL FACTORS AFFECTING FOOT SELF-CARE The literature examining psychological factors underlying adherence to foot self-care is sparse and is mainly restricted to published abstracts.16,17 Vileikyte et al.,16 using the Health Belief Model (HBM),18 investigated the perceived severity of, and vulnerability to, foot complications and perceived barriers to and benefits of foot care.
Intriguingly, patients diagnosed as having neuropathy and no evidence of peripheral vascular disease, despite the fact that the researchers explained the results of the tests, perceived themselves as significantly more vulnerable to gangrene of the feet (a vascular complication) than to foot ulceration (primarily a consequence of having neuropathy).
Although this was an interesting finding, the researchers were unable to explain, within the HBM framework, why neuropathic patients rated their vulnerability to vascular complications as significantly greater than to foot ulceration.
This may be due to the limitations of the HBM outlined by Leventhal and Nerenz19 : although the HBM provides global evaluations of vulnerability to health threats, it lacks content and thus explanatory power for how vulnerability judgments are made.
The study of McKay et al.17 tested the role of personality traits in predicting a series of relatively independent self-management behaviours (diet, exercise, blood glucose testing and foot care) in a sample of 221 users of an Internet-based diabetes support system.
They found that the conscientiousness score was an independent predictor of adherence to foot care.
However, this observation needs to be treated with caution because it was made in a highly self-selected group of patients.
Additionally, the role of personality might have been more fully understood if it had been assessed using the self-regulatory framework, that is, by introducing illness cognition as a potential mediator of the association between conscientiousness and adherence.
Nevertheless, it is an interesting finding and supports a commonly held belief by practitioners that patient’s personality influences adherence to treatment recommendations.
Several other reports, though not explicitly assessing the psychological factors influencing adherence to foot care, point to the possibility that such factors are at play when patients make behavioural decisions respecting preventive foot self-care.
When comparing two groups of high-risk neuropathic patients with and without foot ulcer history, Vileikyte et al.20 reported that although both groups had a sufficient amount of knowledge regarding preventive foot care, scores for self-reported foot care practice were significantly higher in those patients who had experienced a foot ulcer, in comparison to those with no ulcer history.
It could be speculated that the development of a foot ulcer resulted in reappraisal of the health threat, making it more relevant to the ‘self’, more threatening and thus resulting in better foot care practice.
Similarly, Breuer21 showed that adherence to protective footwear was significantly higher in those patients who perceived the health status of their feet as less favourable than those who did not wear the recommended shoes.
These observations indicate that patients’ behavioural decisions are influenced by their representation of the health threat and point to the need for an examination of how diabetic patients at high risk for developing a neuropathic foot ulcer understand their neuropathy and control their risks of developing a foot ulcer.
THE COMMON SENSE MODEL OF ILLNESS BEHAVIOUR The Common Sense Model (CSM) of Illness Behaviour provides a framework for explor- ing how people give meaning and make decisions to take specific actions in response to the
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THE COMMON SENSE MODEL OF ILLNESS BEHAVIOUR 135
diagnosis and symptoms associated with chronic illness.22 The CSM postulates that patients process health-threatening information by constructing common sense disease models or un- derstanding about illness in terms of symptoms and diagnostic labels, antecedent conditions believed to cause illness, expected duration, possibility of cure or prevention and anticipated impact of illness.
Two types of information are integrated when patients construct ‘common sense’ views of their health status: verbal information from other persons, including physi- cians, other patients and family members, and concrete experience of symptoms and physical dysfunction.
Guided by the CSM, studies of patient adherence to treatment for chronic conditions such as hypertension and congestive heart failure indicate that inconsistencies between information provided by practitioners and the patients’ common sense interpretation of medical diagnoses and symptom experience result in non-adherence to treatment recommendations.23,24 Baumann and Leventhal, for example, showed that people with hypertension tend to believe that they can tell when the blood pressure is elevated and use symptoms as indicators as to whether or not to take anti-hypertensive medication.23 More recently, Horowitz and colleagues demonstrated that patients with chronic heart failure perceive it to be an acute medical condition and, as a result, do not manage symptoms on a regular basis and fail to prevent exacerbations.24 The main concept of the CSM can be further illustrated by a clinical example of a patient with painful neuropathy and no evidence of peripheral vascular disease (Figure 11.1).
His common sense understanding or ‘folk’ model that the painful sensations in his feet were caused by poor circulation led him to set as a goal the improvement of the blood supply to his feet: he therefore decided to cut the toe box off the shoes thereby enabling him to ‘wiggle’ his toes, which he believed would improve the circulation.
His actions alleviated pain, thereby confirming his ‘diagnosis’ of poor circulation, and so this individual continued to engage in
Common Sense Model GOAL ACTION RESULT
Vascular model: circulation in feet Circulation Cut the shoe toe box Pain
APPRAISAL Pain in toes when wearing shoes
Allodynia = Removed neuropathic pain induced Exposed non-noxious by non-noxious stimuli, toes to stimulus i.e. pressure from a shoe injury
Biomedical Model DANGER
Figure 11.1 Patient’s Common Sense versus Health Care Provider’s Model of neuropathic pain expe- rience (see text for further discussion)
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136 PSYCHOLOGICAL AND BEHAVIOURAL ISSUES IN DIABETIC FOOT ULCERATION
potentially damaging behaviours (wearing open-toed shoes).
From the medical perspective, his symptoms could be described as allodynia, which improved when the non-noxious stimulus, i.e. the pressure from the shoes, was removed, which then, of course, exposed his toes to potential injury.
This case demonstrates that patients respond to foot complications by constructing their own images or models that may be inconsistent with the biomedical processes underlying the disease.
In the context of neuropathy, it is therefore important to determine whether a patient’s un- derstanding and perception of neuropathy capture the features of this medical disorder that are critical for his/her participation in foot self-care.
For example, do patients understand the nature of neuropathy, i.e. that the absence of symptoms does not indicate that the feet are healthy?
Do they understand how neuropathy may result in foot ulceration and why, for example, it is important to have their feet measured when buying shoes or why regular removal of callus reduces their risk for foot ulceration?
Thus, uncovering the patients’ representations of diabetic foot complications and understanding how patients merge ‘folk’ beliefs with information from practitioners may hold the key to understanding patients’ participation in foot self-care.