PATIENTS’ COMMON SENSE MODELS IN THE INTERPRETATION OF DIABETIC FOOT COMPLICATIONS AND FOOT SELF-CARE The combination of the CSM with clinical experience and evidence from interviews with patients at high risk for foot ulceration has informed the development of the Neuropathy Psy- chosocial Inventory, NPI, an instrument that assesses patients’ representations of neuropathy and foot ulceration.25 A large UK and US study employed the NPI to describe the ways in which the patients’ ‘folk’ beliefs combine with medical information to predict engagement in preventive foot self-care.25 Additionally, it examined the role of foot ulcer history in shaping the patients’ beliefs about diabetic foot complications and foot self-care behaviours.
The re- sults of this prospective study indicate that the majority of patients diagnosed with diabetic neuropathy believe that the development of a foot ulcer would be accompanied by pain.
Ad- ditionally, patients anticipate that any foot damage from diabetes would be vascular and that vascular damage should be reflected in poor circulation and ‘cold feet’.
These ‘folk’ beliefs falsely reassure the patient that his or her feet are healthy, leading to a failure to engage in preventive foot self-care and resulting in similar behaviours to those practised by an individual with intact sensation in the feet (e.g. relying on feeling the fit of the shoes rather than having the feet measured when buying a new pair).
In contrast, patients who accurately interpret the health care provider’s diagnosis, ‘neuropathy’, and realise that it is possible to have a serious medical condition even if the feet are warm and asymptomatic report higher levels of preventive foot self-care.
Furthermore, our results showed that ulcer causal beliefs are among the strongest predictors of preventive foot self-care.
That is, patients who have a coherent picture of how various neuropathic risk factors may lead to foot ulceration are more likely to engage in foot self-care actions that reduce the impact of these risk factors.
Having had a foot ulcer motivates actions to avoid risks and prevent recurrence.
It teaches patients that ‘folk’ beliefs , such as that good circulation means healthy feet , may be inaccurate and that pain is not a necessary feature of foot ulcers.
Moreover, a foot ulcer experience facilitates better understanding of how foot ulcers occur.
This could be simply a reflection of ‘learning by experience process’, e.g.
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an individual who develops a painless foot ulcer while wearing a new pair of shoes realises that footwear, in combination with reduced feeling in the feet, results in ulceration.
As demon- strated by Del Aguila et al.,26 it is also possible that practitioners are more likely to provide information about the health threats when confronted with a patient presenting with a foot ulcer, rather than the risk factors alone.
It is most likely, however, that foot ulcer experience in- teracts with medical information processing in shaping the patients’ perceptions about diabetic foot complications.
Interestingly, beliefs about the nature of neuropathy were independent of foot ulcer history,25 suggesting that foot ulcer experience is not sufficient to teach patients that neuropathy is a core problem underlying diabetic foot complications and that this fact requires additional explanation by the health care provider.
Contrary to the belief commonly held by clinicians that their patients ignore the risks because they use denial as a protective mechanism from being emotionally overwhelmed, Vileikyte25 did not find evidence for curvilinearity: that is, higher levels of fear of amputation were asso- ciated with better foot self-care.
It is important to note that it is not the intensity of fear but the source of fear or the nature of beliefs underlying emotion that is critical.
For example, while fear of complications may lead someone who has poorly controlled diabetes on tablets alone to seek medical care, fear may result in avoidance behaviours if it is the potential treatment (e.g. insulin) that is feared.
Moreover, while specific emotion of worry about foot ulcers and ampu- tation appears to motivate preventive actions, generalised (non-specific, not related to illness) anxiety does not seem to affect foot self-care actions.
These observations are consistent with increasing research evidence that emotional responses that are attached to specific aspects of illness (fear of threatening outcomes such as cancer, AIDS) are important predictors of health care behaviours in contrast to the weak and inconsistent relationships of illness behaviours with measures of generalised distress.27,28 Finally, of the five personality traits (neuroticism, conscientiousness, intellect, extraversion and agreeableness) and personality-like characteris- tics (hostility), only conscientiousness was significantly associated with better foot self-care.25 It appears that conscientiousness affects foot self-care actions both directly and indirectly; that is, conscientious individuals are likely to have more accurate understanding about neuropathy and foot ulceration.
These findings strongly suggest that the patients’ common sense beliefs about foot compli- cations are important determinants of a lack of foot self-care and that the health care provider’s ability to identify these misperceptions and correct them, by communicating clear messages about the nature of neuropathy, is pivotal for insuring effective patient foot self-care.
Finally, loss of pain sensation not only impacts adherence to preventive foot self-care, but also results in a lack of adherence to prescribed foot ulcer treatment (wearing a foot ulcer offloading device to reduce mechanical stress) and contributes significantly to non-healing of foot ulcers.29 Whereas persons with foot lesions in the absence of neuropathy avoid walking on such wounds because of pain, patients with insensitive feet continue to walk on plantar ulcers.
This, in turn, prolongs the patients’ physical and psychosocial dysfunction, including restrictions in activities of daily living and associated emotional distress.30
FOOT ULCERATION AND DEPRESSION: IS THERE A LINK? Foot-ulcer-specific emotional responses are prominent and include fear of potential conse- quences and anger directed at health care providers as a result of a perceived lack of timely and clear explanation about foot complications.25 However, there is no evidence in the literature
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138 PSYCHOLOGICAL AND BEHAVIOURAL ISSUES IN DIABETIC FOOT ULCERATION
for the association between foot ulceration and depressive symptoms.
Vileikyte and colleagues have investigated both cross-sectionally31 and prospectively32 the relationship between active foot ulcers, the development of a new ulcer during the18-month follow-up and depression scores and found no association between foot ulceration and depression.
Similarly, Ismail and colleagues have examined the role of depression in recurrence and healing of foot ulcers over the 18-month period in patients presenting with the first episode of foot ulceration and showed that depression is not predictive of foot ulcer recurrence or healing.33 Furthermore, Willrich et al., using the Zung Self-Rating Depression Scale and the Short-Form (SF)-36 questionnaire, have demonstrated that while foot ulcers and Charcot neuroarthropathy have negative effects on patients’ physical and mental functioning, this does not seem to be associated with clinical depression.34 Moreover, Lin et al. have examined the relationship between depression and various diabetes self-care activities and have found that depression was associated with poorer exercise, diet and medication adherence but not with preventive foot selfcare.35 The lack of a link between foot ulceration and depression is somewhat unexpected, in view of the evidence that foot ulcers are associated with severe restrictions in mobility, loss of work time and other disruptions in activities of daily living.
A possible explanation for this could be that the levels of physical disruptions caused by foot ulceration do not reach those needed to produce depression.
It could also be possible that patients affected by foot ulceration receive sufficient social (family and medical) support, which may act as a buffer against depression.Additionally, other psychosocial variables, such as a perceived lack of treatment control and chronic duration of illness, known to be important determinants of depression may not be sufficiently pronounced in patients experiencing foot ulceration to cause depression.
Although foot ulcers are difficult to treat and do take a long time to heal, they usually are curable and thus of limited duration.
It is important to remember, however, that even though foot ulceration is not associated with depressive symptoms, other experiences of neuropathy such as pain and unsteadiness are important predictors of depression in this group of patients.
Therefore, persons with diabetic neuropathy have an increased risk for depressive symptoms and should be carefully monitored to determine whether they are depressed and provided with treatment or referral as necessary.