LEARNING OUTCOME AND OBJECTIVES:  Upon completion of this course, you will have gained up-to-date knowledge to care for individuals at risk for developing diabetic foot ulcers and to assess and treat those with diabetic foot ulcers. Specific learning objectives to address potential knowledge gaps include:

• Identify the prevalence and impacts of diabetic foot ulcers.
• Describe the elements of an interdisciplinary approach to care.
• Discuss the importance of effective patient teaching.
• Summarize the importance of preventive measures for diabetic foot care.
• Describe the role of diabetic peripheral neuropathy and Charcot osteoarthropathy in the development of diabetic foot ulcers.
• List the steps that comprise a foot assessment in patients with diabetes.
• Summarize the management program for patients with diabetic foot ulcers.
• Describe the important components of off-loading in the prevention and treatment of diabetic foot ulcers.
• Discuss amputation as it relates to diabetic foot ulcers.

INTRODUCTION

A diabetic foot ulcer (DFU) is the most frequently occurring complication associated with diabetes and one that healthcare providers will encounter across the continuum of care. Diabetic foot ulcers are complex, chronic wounds that are often disabling and greatly impact the morbidity and mortality of patients. Patients who develop a DFU are at higher risk of early death, heart attack, and fatal stroke than people with diabetes who do not develop diabetic foot ulcers. Data shows that 40%–70% of those with a DFU will end up with a lower limb amputation (Cheng et al., 2021).

Various definitions of a diabetic foot ulcer include the following types of wounds on the foot of a patient with diabetes:

• A wound that can develop in persons with diabetes; the most frequent site for a diabetic foot ulcer being the plantar surface of the foot and the toes (APMA, 2021a)
• An open area developing on the lower extremity of a person who has diabetes (Wound Source, 2019)
• Areas of callous or blisters on the foot that eventually break down and become open wounds (WOCN, 2021)

Diabetic foot ulcers can occur in patients with either type 1 or type 2 diabetes.

History of Diabetes

Diabetes is one of the oldest diseases known to humanity and was first documented by an Egyptian physician around 1552 BCE. The term diabetes is Greek and means “to syphon.” It was first used around 250 BCE by the Greek physician Aretaeus, who noted how quickly diabetes drained fluid from those affected by it (Healthline, 2018).

By the fifth century, the Chinese had noted that people with diabetes were more prone to infection, and in Baghdad in the fifth century, it was observed that people with diabetes developed gangrene in their extremities. In China and India, they realized that there was a difference between type 1 and type 2 diabetes, with the latter occurring more frequently in overweight, wealthy individuals compared to their less well-off counterparts. During the 18th century, diabetes was discovered to be a systemic disease (Herscovici, 2016; Higuera, 2020).

In the Middle Ages, it was thought that diabetes was a disease of the kidneys, but it was discovered in the late 18th century that diabetes afflicted those who had pancreatic damage. It was also observed that while diabetes was fatal in some persons, it remained a chronic disease in others, further clarifying the distinction between type 1 and type 2 diabetes (Higuera, 2020).

In the early 19th century, it was found that restricted diets were beneficial to persons with diabetes and that calorie intake was important to the progress of the disease (Diabetes.co.uk, 2019). In the 20th century several discoveries and advances were made in the diagnosis and treatment of diabetes. Several of the most notable are described in the table below.

HISTORY OF DIABETES CARE

(ADA, 2014; Higuera, 2020)
1916	Dr. Elliot Joslin published the first edition of The Treatment of Diabetes Mellitus. Dr. Joslin was known worldwide as a clinician and educator and one of the leading advocates in diabetes care.
1921	Dr. Frederick Banting and Dr. Charles Best (Banting’s student at the time) discovered insulin.
1923	Eli Lilly and Company started producing insulin commercially.
1936	Sir Harold Percival Himsworth published a research paper that differentiated between type 1 and type 2 diabetes.
1940	The American Diabetes Association was created to tackle the increasing prevalence of diabetes and the complications that develop as a result of the disease.
1949	Dr. Rachmiel Levine discovered that insulin transports glucose into the cells in the body.
1972	The association between elevated blood sugar levels and disease of the blood vessels was reported.
1978	The first human-based insulin was developed and named Humulin. It has the exact same structure as human insulin.
1989	The American Diabetes Association announced its first Standards of Care to better assist physicians in the treatment of diabetes.
1993	The Diabetes Control and Complications Trial demonstrated that keeping blood sugar levels as close as possible to normal slowed the onset of diabetic complications.
1996	The first short-acting insulin, Lispro, was launched in the market.
1990s	External insulin pumps were invented.

After the discovery of insulin, the treatment of diabetes was revolutionized. With further advances in refining and producing insulin commercially, diabetes evolved from being an acute condition with a limited life expectancy to being a chronic condition. Consequently, patients’ longer lifespans resulted in their developing complications related to diabetes, such as diabetic foot ulcers, that required new practices to address them.

Types of Diabetes

Diabetes is not a single disease; rather, it is a condition that includes several metabolic disorders caused by problems with insulin secretion, the manner in which insulin acts in the body, or a combination of both of these.

Diabetes has several forms. Three of the most frequently occurring forms are:

• Type 1 diabetes (previously referred to as juvenile-onset diabetes) usually occurs in children and young adults. Between 5%–10% of people with diabetes have type 1. Type 1 diabetes occurs when the body is unable to produce insulin due to an autoimmune destruction of the insulin-producing cells (beta cells) in the pancreas.
• Type 2 diabetes (previously referred to as adult-onset diabetes) comprises approximately 90% of all people with diabetes. Type 2 diabetes results from a combination of factors, insulin resistance, and a progressive reduction in insulin secretion. Previously, this form of diabetes was typically associated with older adults, but it is now occurring more frequently in young people, adolescents, and children.
• Gestational diabetes is found in women during the second and third trimesters of pregnancy, and it can continue beyond delivery. Its symptoms resemble those of type 2 diabetes, and women who experience gestational diabetes are more prone to develop type 2 diabetes later in their lives.
  (WHO, 2021)

Epidemiology of Diabetes and Diabetic Foot Ulcers

Type 2 diabetes is now the most rapidly growing chronic condition globally, with over 300 million people worldwide affected. These figures are projected to almost double by the year 2035. Since the possibility of developing diabetes increases with age, the percentage of older adults with diabetes is set to increase along with the increasingly older population.

In 2019, approximately 1.5 million deaths globally were a direct result of diabetes. Between the years 2000 and 2016 there was a 5% increase in the rate of premature deaths related to diabetes. The premature mortality rates dropped in well-developed countries from 2000 to 2010, however there was an uptake in the rates again from 2010 to 2016. In developing countries, the premature mortality rates trended upward in both time frames (WHO, 2021). Figures indicate that 80% of persons with diabetes live in low- and middle-income countries (Abbas, 2019).

The impact of diabetes and the complications arising from it are expected to cause greater damage and have more devastating consequences in developing countries compared to those that are affluent. Data indicate that persons with diabetes in developing countries have a higher incidence of cardiovascular disease, in part due to uncontrolled hypertension and uncontrolled dyslipidemia. Healthcare systems in these parts of the world also do not have the capacity for routine screening for complications related to diabetes, such as retinopathy and kidney disease. Diabetic foot ulcers and lower limb amputations are also more prevalent in developing countries (Smokovski, 2021).

A Global Overview of Diabetes Care

There is a wide variance in the diagnosis and treatment of diabetes and diabetic foot ulcers in different parts of the world. A prevailing factor across the developing world is the lack of diabetes education for patients and the lack of up-to-date education on diabetes care for healthcare providers. According to the International Diabetes Federation, 20% of healthcare providers worldwide don’t receive postgraduate training in diabetes care (Smokovski, 2021).

ASIA

The causes of diabetic foot ulcers are related to inadequate diagnosis, often not occurring until foot problems are advanced and serious infection is present.

• In China, research shows that there is a scarcity of foot clinics.
• India is noted to have significant number of persons with diabetes and a high incidence of lower extremity amputations.
  (Zubair et al., 2021; Abbas & Bal, 2019)

AFRICA

There were 19 million persons in Africa with diabetes at the end of 2019. If the current trends continue, this number is estimated to reach 29 million by the year 2030 and 47 million by the year 2045. The care of diabetic foot ulcers in Africa is complicated by several factors, including:

• There is an extended time period from the development of a foot ulcer to treatment by a healthcare professional.
• Seeking treatment from traditional healers is widely prevalent, as is self-treatment of wounds.
• Knowledge deficits of treatments among healthcare workers contributes to poor outcomes among patients with diabetic foot ulcers.
  (Zubair et al., 2021)

AUSTRALIA

In Australia the yearly occurrence rate of diabetic foot ulcers in persons with diabetes is 2%. Members of the Aboriginal population who have with diabetes are considered to be at the greatest risk for developing diabetic foot ulcers. Statistics indicate that:

• 50,000 people are living with diabetic foot disease.
• 12,500 people are living with a diabetes-related amputation.
• Around 12 people will have a diabetes-related lower extremity amputation each day.
  (Van Netten et al., 2018; DFA, 2021; Diabetes Australia, 2021)

EUROPE

Approximately 55 million people in Europe have a diagnosis of diabetes, and 8 million of these are at risk for developing a diabetic foot ulcer. Geographic disparities relating to diabetic foot care include:

• Only a small number of countries in Eastern Europe have foot clinics and offer podiatry care.
• Regardless of the differences in healthcare across Europe, delays in referrals for specialized foot care is common.
  (Zubair et al., 2021; Manu et al., 2018)

Diabetes in the United States

In the United States, 34.2 million individuals (about 1 in 10) have diabetes, and 88 million (about 1 in 3) have prediabetes. Statistics show that new cases of type 2 diabetes are occurring in greater numbers among ethnic and racial minorities (CDC, 2020a). Data also show that prediabetes is more prevalent among men (37%) than women (29%) (NIDDK, 2020).

Neuropathy is one of the most prevalent risk factors for diabetic foot ulcers (Baranoski & Ayello, 2020). Statistics indicate that approximately 15% of individuals with diabetes that is complicated with neuropathy will develop a diabetic foot ulcer at some point during their lives. Between 14%–24% of those who develop a diabetic foot ulcer will progress to amputation (WOCN, 2021).

U.S. research data indicate that approximately 85% of lower extremity amputations are a consequence of diabetes and begin with a diabetic foot ulcer. After an amputation, the mortality rate rises according to the level of amputation (the higher up on the extremity the amputation occurs, the greater the mortality rate) and varies from 40%–70% at the five-year mark post amputation. This places the mortality rate associated with amputations in the same category as that from several malignancies (WOCN, 2021).

DIABETES AMONG YOUTH

Diabetes is one of the most frequently occurring chronic conditions among youth. Research shows that the rates of both type 1 and type 2 diabetes continued to increase among youths from 2011–2015. Data showed that for both types of diabetes the rates of increase were generally greater among racial and ethnic minorities than among the White population (CDC, 2020b).

When type 2 diabetes occurs in children and adolescents, it is a much more aggressive disease than in adults. Whereas in adults there is a considerable length of time between diagnosis and the appearance of diabetic complications, in children it has been found that complications can start developing within a few years of disease onset (Lascar et al., 2018). Thus, clinicians will be treating much younger patients for the complications of diabetes, including diabetic foot ulcers.

DISPARITIES AMONG ADULTS WITH DIABETES

There are racial, ethnic, economic, and age disparities in the development of type 2 diabetes. In the United States, the highest percentage of newly diagnosed diabetes cases is found in the Native American and Alaskan Native populations (CDC, 2020b).

African Americans are approximately twice as likely to be diagnosed with diabetes as non-Hispanic Whites (CDC, 2020a). Complications from diabetes are also more common in this population, including lower extremity amputation. In 2017 non-Hispanic Black people were 2.3 times more likely to end up in the hospital for a lower extremity amputation in comparison to non-Hispanic White people (Office of Minority Health, 2021).

Socioeconomic status also plays a significant role in the prevalence of type 2 diabetes. Research reveals that living in poverty is a factor that can double or triple the risk of developing diabetes. The risk for uncontrolled diabetes increases when patients have the bare resources to pay for their basic needs of housing, food, and utilities in addition to difficulties in paying for medications and supplies to monitor blood sugar levels. Living in poverty also increases the likelihood of developing complications related to diabetes (Hill-Briggs, 2021).

Foot ulcers are the most serious, disabling, and costly complication of diabetes. They most frequently occur in older adults who have had diabetes for several years. Patients ages 65 years and over with diabetes have a two-fold increase in the risk of developing a foot wound and also have the highest number of major lower extremity amputations resulting from diabetes (Zubair et al., 2021; WOCN, 2021).

ECONOMIC IMPACT

Diabetic foot ulcers are costly to treat. Studies show that patients with diabetic foot ulcers have more emergency room visits, spend more days in the hospital, and require more home healthcare services than patients with diabetes but without diabetic foot ulcers (WOCN, 2021; Baranoski & Ayello, 2020).

The National Diabetes Statistic Report indicates that the total estimated direct and indirect costs of diabetes care in the United States in 2017 was $327 billion. From 2012 to 2017, the cost of medical care related to diabetes increased from $8,417 to $9,601 per person (CDC, 2020a).