Depression - diabetes - diabetic foot ulcer
Introduction
Diabetes is a lifestyle disease of the 21st century. Regardless of the increasing awareness of diabetes, it continues to represent
both a national and global health challenge, with estimates that 280 Australians are
diagnosed with diabetes every day, and approximately 366 million people were diagnosed
with diabetes worldwide in 2011.[1]
[2] Despite improvements in treatments for patients with diabetes, complications of
this disease continue to grow, placing an increased cost burden on the public health
system.[2] Diabetic foot complications are the most common reason for diabetic hospital admissions
with 12-25% of patients with diabetes developing a diabetic foot ulcer (DFU).[3]
[4] Depression is frequently linked to diabetic complications.[5] "Neither the mechanism for the co-occurrence of diabetes and depression nor the
directional pattern of causality is known, yet the relationship and its implications
are clear".[6] There is strong evidence linking depression as a risk factor for the development
of type 2 diabetes and its potential to accelerate diabetes complications, with recent
research showing a biological link between depression and diabetes symptoms.[7]
The links between depression and exacerbations of health problems, adverse effects
on general functioning and quality of life, lower self-care regimens, and poorer glycemic
control in people with diabetes are well-established.[8]
[9] The link between depression and DFUs is less clear, and there is clearly a need
to investigate this relationship further. Previous studies have investigated the biological
aspects of DFU healing rates such as pressure management, wound factors, and vascularity.
These factors and their influence on wound healing are well-understood. A deeper understanding
of the influence depressive symptoms may have on healing rates of DFUs is needed to
best target appropriate clinical interventions.
The aim of this paper was to comprehensively review recent literature (1988-2013)
linking DFUs and depression symptoms, with specific focus on the impact depressive
symptoms have upon healing rates. We conclude by discussing the complexities of the
relationship between DFUs and depression on individuals and clinical healthcare management,
and outline areas where further research is warranted.
Depression and Diabetes
The term depression is used in many different ways: From describing transient states
of low mood experienced by all people at some time in their life, through to severe
psychiatric disorders.[10] Depression in this article will refer to clinical depression as defined by The Diagnostic
and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).[11] Depression is estimated to become the second most prevalent cause of disease burden
and the major cause of disability worldwide by 2020.[12] Over the past 20 years, a number of studies including meta-analyses and systematic
reviews have consistently shown that the prevalence of depression in people with diabetes
is two to three times more common than the general population.[13]
[14]
[15]
[16] The principal conclusion of these reviews was that diabetes doubles the odds of
depression, no matter what the subject group, sex, type of diabetes, or assessment
method used.[14]
The negative impact of depression on individual′s quality of life, leading to functional
decline, plus the additional burden it has on family members and caregivers, has been
well-established.[8]
[9]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25] A number of studies have highlighted that depressive symptoms reduced the quality
of life in people with diabetes due to somatic symptoms and complications.[6]
[26]
[27] These symptoms have been linked with both metabolic and behavioral risk factors
for type 2 diabetes.[28] People with depression are less likely to comply with dietary advice[29] and more likely to be physically inactive,[19]
[20]
[21]
[22]
[23]
[25] and thus have an increased risk of obesity. This corroborates findings from earlier
studies that depressed individuals have higher caloric intake,[21]
[30] and are less physically active.[19]
[20]
[21]
[22]
[23]
[25] A conclusion drawn by the significant longitudinal study into depressive symptoms
and incidents of diabetes is that socioeconomic status may act either independently
or in combination to influence health-related behavior.[19] An individual with a lower socioeconomic level may be more inclined to consume a
diet higher in saturated fats, carbohydrates, and alcohol, as well as maintaining
a more sedentary lifestyle leading to a higher predisposition to diabetes.[19]
One of the most significant longitudinal studies conducted over 21 years, established
that subjects who were found to have the highest levels of depressive symptoms, developed
the highest levels of reported diabetes over time, from baseline.[19] The very large sample size and length of study undertaken by Carnethon et al.,[19] carries significant weight, with its conclusions, validity, and reliability into
the mediating effect of depression upon diabetes. Subjects who developed higher levels
of depressive symptoms over the 21 years were found to be at an elevated rate of 2.52
times more likely to develop diabetes.[19] Further analysis found that those with a low level of education and depressive symptoms
were three times more likely to develop diabetes when compared to subjects with higher
levels of education.[19] The main limitation of this study was that diabetes levels were only assessed by
self-report or from medical records and not a clinical test such as the HbA1c.
Amongst the elderly population, diabetes rarely exists in isolation,[31] with impairment, disability, and higher rates of complications found in patients
with both depression and diabetes compared to people with either one of these conditions
alone.[31]
[32]
[33]
[34] This is further supported by past research indicating a positive relationship between
depression and diabetes, with depressive symptoms leading to an exacerbation and acceleration
of the onset of diabetes symptoms and complications.[32]
[35]
[36]
[37]
[38]
[39]
[40]
[41] Interesting findings in the research by Golden et al.,[7] found that the association between diabetes and depression was not the same for
all individuals, and in fact varied with the treatment of diabetes. The suggestion
was that requirements in monitoring and treating an individual′s diabetes may lead
these individuals to elevated depressive symptoms compared to those who did not treat
their diabetes.[7] Further research has found the association between type 2 diabetes and incidents
of depressive symptoms decreased following adjustments for diabetes comorbidities,[42] thus suggesting that complications of diabetes may be more influential in developing
depressive symptoms than diabetes itself.
Biological Relationship
Golden et al.,[7] stated that the biological mechanisms by which depression and type 2 diabetes are
associated remains unclear despite research into the bidirectional association between
these two long-term conditions. However, numerous studies allude to linking these
two conditions by an inflammatory response at a cellular level,[43]
[44] which increases the activation of the hypothalamic-pituitary-adrenal axis. Some
population studies[45]
[46] reported that this inflammation is associated with the development of diabetes through
limiting insulin uptake, leading to resistance.[35]
[43]
[44]
[45]
[46]
[47]
[48]
[49] One suggested association is that obesity or atherosclerosis is associated with
low-grade inflammation prior to the onset of diabetes.[16]
[19]
Depression and Diabetes Self-Care
Depression and Diabetes Self-Care
Effects of depressive symptoms on a client′s ability to self-care have been explored,[50] with symptoms such as reduced energy, appetite, and motivation, plus the cognitive
effects associated with depression, impacting individual′s ability to self-care.[51] The term ′diabetes burnout′ was coined by Barnard et al.,[2] to report the feeling of diabetes controlling people′s lives, including being overwhelmed
and defeated by diabetes and frustrated by the required self-care regime.[2]
[50]
The concept of self-efficacy is important for self-management behaviors for individuals
with diabetes.[15]
[50] Research has found that an individual′s ability to comply with treatment directions,
instructions, medical adherence, and appropriate preventative care for their diabetes,
such as dietary regimes and exercise is diminished when higher levels of depression
are present.[52] This concept of diminished self-efficacy impacting on an individual′s management
of their condition is supported by a controlled trial confirming the hypothesis that
people with depression were more likely to engage in behavior known to increase the
risk of developing diabetes, and that people who had diabetes complications were more
likely to develop depression.[53]
There is some limited evidence that interventions to improve depression lead to improvements
in general health outcomes;[54] however, other studies have shown that significant improvements in depression levels
do not always lead to improved glycemic control.[55] The almost exclusive focus in previous research on the burden of managing diabetes,
and the impact on an individual′s ability to self-care, has according to Vileikyte
et al.,[56] neglected to include the chronic complications of diabetes and their effects on
an individual′s mental health. There is evidence that by improving other comorbidities
of diabetes, it is possible to improve depression levels and the ability to self-care,
while also reducing the impact of diabetes.[7]
[22] Complications of diabetes, such as neuropathy and subsequent DFUs, have a significant
impact on patients′ adherence behaviors, not just their ability to self-care.[56] Research into these adherence behaviors has led to improvements in the methods and
education, and information is delivered to patients with an aim to empower individuals
in the management of their condition. When patients can be effectively engaged in
their treatment, and responsibility for their own care is promoted, health outcomes
have been shown to improve.[55]
The current focus on physical factors alone has not led to significant reductions
in diabetes complications, since a medical model of treatment focuses primarily on
adherence to medication. Adopting a more balanced approach and considering the psychological
factors associated with diabetes and its complications, may lead to an improvement
in treatment outcomes. A longitudinal study investigating the predictors of depression
in diabetic patients with peripheral neuropathy (PN) has established that, in patients
with diabetes, PN is linked to depressive symptoms and results in activities of daily
life (ADL) restrictions and lower self-perceptions.[57]
[58] This research also established that more severe levels of PN were associated with
strong depressive symptoms, and that these worsened over time.[58] There was also a strong link between an increase in depressive symptoms when combined
with a decline in PN-related physical and psychosocial functioning, indicating that,
as PN increases its influence on other aspects of life, depression also increases.[58] This is directly relevant to patients with a DFU, as neuropathy is the direct precursor
to DFU. The occurrence of a DFU is due to the underlying PN experienced by patients
with diabetes.
Screening for Depression
As there is an established link between depression and diabetes, a review of diabetes
care guidelines for the screening of depression finds a variety of recommendations.
The International Diabetes Federation (IDF) states that healthcare professionals should,
in communicating with a person with diabetes, adopt a whole-person approach and respect
the person′s central role in their ongoing diabetes education and care.[59] There is no specific mention of management of psychological disorders or their impact
on diabetes management. Other national and international guidelines are more specific
with respect to psychological disorders. By comparison, the British National Institute
of Health and Clinical Excellence (NICE) states that:
"Diabetes professionals should ensure they have appropriate skills in the detection
and basic management of non-severe psychological disorders, while arranging prompt
referral to specialists of those whom psychological difficulties continue to interfere
significantly with their well-being or diabetes self-management."[60]
Once detected, it is recommended that:
"The psychological needs of people with diabetes should be addressed in an organized
and planned way and that the individual′s psychological status (including cognitive
dysfunction) should be assessed periodically, with outcomes and clinical implications
discussed with the patient".[60]
The American Diabetes Association (ADA) guidelines go slightly further, stating that
"assessment of psychological and social situations should be included as an ongoing
part of the medical management of diabetes".[61] They specifically state that:
"Psychosocial screening should examine attitudes about the illness, expectations of
medical management and outcomes, affect and mood, general and diabetes-related quality
of life, resources (financial, social and emotional) and psychiatric history."[61]
Screening should be provided for psychosocial problems such as depression, diabetes-related
distress, anxiety, eating disorders, and cognitive impairment; particularly when self-management
is poor.[61]
The Australian National Evidence Based Guidelines for the Management of Type 2 Diabetes
Mellitus briefly touches on the need for psychosocial management,[62] yet in much less detail than the NICE or the ADA. The National Evidence-Based Guidelines
on Prevention, Identification and Management of Foot Complications in Diabetes what
was approved by the National Health and Medical Research Council (NHMRC) in 2011 goes
into extensive detail on the screening process for ′at risk′ subjects for DFUs and
the evidence-based management of DFUs. This guideline, however, does not mention or
refer to depression or depressive symptoms, and the effect this has on patients with
or at risk of DFUs.[63]
In some quarters there is a reticence to discuss psychosocial factors with patients,
due to the perceived emotional impact that raising such topics may have. A systematic
review and meta-analysis on the emotional impact of screening for disease found no
evidence of any adverse emotional impact from undergoing a screening process, and
reported that their findings are consistent with psychological theories of self-regulation
through maintaining emotional equilibrium while managing threats.[64]
[65] It was concluded that provided standard principals of screening were met, there
was no adverse or long-term emotional impact when screening for a disease.[64]
Dfus-Cause and Cost
In Australia in 2005, there were about 10,000 hospital admissions for diabetes-related
foot conditions, and over 1,000 people with diabetes died as a direct result of lower
limb ulceration, with this representing 8% of all diabetes-related deaths.[66]
[67] PN which affects around 30% of people with either type 1 or type 2 diabetes, is
the major predisposing disorder for diabetic foot disease,[68] with foot deformity, trauma, peripheral arterial disease, and infection being further
complicating factors that can prevent or delay ulcer healing.[69]
[70]
[71]
The direct cost of treating a DFU and its associated complications is significant
when compared to the cost of preventing a DFU. The average cost of preventive care
was $ A1,220 compared with $ A7,260 for the treatment of an ulcer.[72] When hospitalization was required, the cost of treatment increased to $ A12,474.[72] When a DFU leads to lower extremity amputation, the median inpatient cost per admission
was $ A12,485 (confidence interval (CI): $ A6,037-24,415), with a median length of
stay of 24 (10-43) days.[66] In 2007, the direct costs of managing diabetes and its complications in the US was
US$116 billion, with 33% of these costs directly related to the management of DFUs.[74] A review in 2012 of the annual cost to treat DFUs in the UK was found to be over
ͳ600 million.[75]
The national guidelines on detection and prevention of diabetic foot problems in Type
2 diabetics, has not considered the direct influence of depression or any mental health
disorder on foot ulcers.[72] There is also no consideration of mental health influences, specifically depression
and its relationship with DFUs, within the multidisciplinary evidenced-based clinical
guideline for the assessment, investigation, and management of diabetes-related foot
complications.[76] Recent research has established the association between severity of PN symptoms
and depressive symptoms.[57] The results however were counterintuitive, as they did not demonstrate a significant
association between DFUs and depressive symptoms. A possible conclusion outlined by
this research is the fact that DFUs are painless, thus subjects have little emotional
distress or discomfort from DFUs compared to PN pain, which can be unpredictable.[57] A more recent publication investigated the causal relationship between depression
and DFUs, finding a significant interaction between depression and the occurrence
of the first DFU; however, this relationship did not extend to recurrent foot ulcers.[77] This study demonstrated a strong relationship between the biological, psychological,
and behavioral risks of foot ulcers, and the independent risk factor of depression,
and suggested that the relationship between depression and a DFU is independent of
any biological risk factors or foot self-care.[77] The conclusion stated that interventions that target depression and foot self-care
behaviors prior to the occurrence of a DFU could maximize the successful prevention
of an ulcer.[77]
There is strong evidence suggesting that stress can disrupt the body′s ability to
heal wounds.[78] Wound healing is a biological process, achieved through specific phases: Hemostasis,
inflammation, proliferation, and remodeling. For successful healing to occur, all
four phases must occur sequentially and in a reasonable time frame. The disruption
stress places on this process can be significant and can lead to healing delays; however,
most research has focused on acute wounds and not chronic ones, such as DFUs.[79]
Measuring Depression and Moving Forward
Measuring Depression and Moving Forward
Regardless of the well-documented prevalence of depression in diabetic patients, there
remains little emphasis on the psychological aspects of diabetes in contemporary healthcare.[80] The evidence linking a concurrent diagnosis of depression and diabetes to an increased
mortality, a lower level of self-care, and an increased risk of poor or even nonhealing
of DFUs, should prompt treating clinicians to be more aware of a patient′s ability
to cope on a day-to-day basis with both their diabetes and psychological malaise.[81] Despite healthcare providers recognizing psychological symptoms in many patients,
only 10% in Australia are referred for psychological assessment or care.[80]
National evidenced-based guidelines on type 2 diabetes mellitus conclude that a multidisciplinary
specialist foot care team can reduce ulcerations and amputations in people with high-risk
feet.[72] The increased movement towards multidisciplinary foot clinics could include an increased
awareness and management of patient′s depression. Community health clinics, outpatient
departments, and multidisciplinary foot clinics are well-positioned to initially identify
people with, or at risk of, significant depressive symptoms, as well as monitor people
over time. This may contribute to improved treatment adherence and quality of life,
as well as reduced healthcare costs for persons with diabetes, since there is increasing
evidence that primary care staff can be trained in basic psychological interventions
for depression.[82] There exists a number of easily administered depression scales for the healthcare
provider to make better informed decisions on when and how to provide appropriate
mental health referrals for patients.[83] When depression is stabilized, patients have been shown to be able to engage more
readily in self-management activities, which will help improve their depression, diabetes,
and quality of life.[15]
Conclusion
It is clear from the existing literature that the healthcare costs of treating long-term
neuropathic DFUs are significant.[66]
[72]
[75] It is also well-established that there is a strong link between diabetes and depressed
mood, with depression in this population contributing to increases in morbidity and
mortality.[13]
[14]
[15]
[16]
[31]
[34] The recent evidence of a substantial relationship between depression symptoms and
DFU rates; with every standard deviation increase in depressive symptoms, associated
with a 68% increase in risk of DFU, substantiates the need for further research in
this area.[77] Despite the observed prevalence of depressive symptoms by healthcare professionals
in Australia[80] and the recommendations of international guidelines that psychosocial symptoms need
to be managed along with diabetes care,[60]
[61] depression remains underrecognized and undertreated in the DFU patient population
in Australia. The complex interaction between depression and diabetes has been established
in diabetics with PN;[57]
[58] however, the addition of DFU has further implications for the individual′s capacity
for self-care,[55] and potentially increases the psychological impact of diabetes. With depression
levels also known to be influenced by activity restriction, further research into
the relationship between the limiting of activities of daily living for individuals
with a DFU and levels of depressive symptoms is required.
This is where the integration of mental health specialists into the multidisciplinary
treatment of patients with a DFU could assist in negotiating the specific balance
between the medical and psychological model of treatment. Earlier intervention, diagnosis,
and management of patients′ depression may have implications for improved healing
rates and reduced healthcare costs, not only in patients with PN as established,[57] but also for those with DFUs as well. At this time there has been no published research
investigating the relationship between depressive symptoms and healing rates of DFUs
in Australia, and further research in this area is recommended.
How to cite this article: Steel A, Reece J, Daw AM. Understanding the relationship between depression and diabetic
foot ulcers. J Soc Health Diabetes 2016;4:17-24.
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