By Bruce E. Ruben MD

In order to heal a wound, the body needs oxygen, nutrients, energy and a fully functioning vascular system that brings those resources to the wound and takes waste products away from the wound.

So it follows that any medical condition that diverts those resources from a wound could be considered a comorbidity or cofactor that inhibits wound healing.

There are hundreds of specific medical conditions that can inhibit or even prevent wounds from healing. Below are some of the more general and easily identifiable conditions.

Comorbidity #1: Diabetes

When it comes to making energy available to a wound site with good vascularization, diabetes is a major limiting factor and comorbidity in wound healing. According to the National Institutes of Health and the CDC, more than 25 million Americans have diabetes. Approximately 15% of those patients will develop a foot ulcer at some point as foot ulcers are the most common wounds for diabetics.

The wound healing problems for diabetics begin when elevated blood sugar levels stiffen the arteries and cause blood vessels to narrow. This narrowing leads to decreased blood flow and oxygen to the wound. An elevated blood sugar level also decreases the function of red blood cells that carry nutrients to the tissues, which, in turn, lowers the efficiency of the white blood cells that fight infection.

Comorbidity #2:Diabetic Neuropathy

Diabetes is an insidious disease that targets the smallest arteries and nerves and also the arteries and nerves located farthest from the heart. That’s why individuals with diabetes often suffer loss of sensation, called diabetic neuropathy, in their toes and feet. That means they may not be able to feel a developing blister, infection or surgical wound problem.

Comorbidity #3: Infection

Infection is one of the five primary reasons why a wound won’t heal. Considering that the body makes about 11 trillion fresh white blood cells every day, you might think germs don’t stand a chance against such a formidable army. In fact, they usually don’t. It’s rare that an organism on the wound surface causes the infection. But occasionally, the number of bacteria living on the skin’s surface is too great, or there are other cofactors involved that allow normally benign bacteria to proliferate and become destructive. The organisms compete with new tissue for nutrients and oxygen, and their byproducts are damaging to wound healing by creating an environment for infection to develop and advance.

Comorbidity #4: Immune System Deficiency

On the opposing side of infections is the immune system, which is the body’s natural defense mechanism against infection. However, some conditions such as diabetes, multiple sclerosis, asthma and lupus can have a negative impact on the body’s ability to fight infection.

For example, the high blood sugar levels that identify diabetes cause the immune cells to function ineffectively, thereby raising the risk of infection. Left untreated, infection can also raise the risk of developing other serious medical conditions such as gangrene, sepsis or a bone infection like osteomyelitis.

Comorbidity #5: Arterial and Venous Insufficiencies (Peripheral Vascular Disease)

In order for wounds to heal, they need good blood supply flowing to the wound site and good blood flow going away from the wound site. With arterial insufficiency, there is inadequate oxygen- and nutrient-enriched blood flowing to the wound site, which results in delayed healing.

Atherosclerosis, the buildup of fat, cholesterol, and other substances in the walls of arteries, is a cofactor in non-healing wounds and the most common cause of arterial insufficiency of the lower extremities. Patients with a higher risk for atherosclerosis may have a history of:

• Abnormal cholesterol
• Diabetes
• Heart disease (CAD)
• High blood pressure (hypertension)
• Kidney disease involving hemodialysis
• Smoking
• Stroke (cerebrovascular disease)

With venous insufficiency, the veins leading away from the wound are malfunctioning, thereby causing blood, lymph and dead cells to pool around the wound and in the lower legs. This condition stalls the healing process and presents a greater risk of infection to the patient.

Comorbidity #6: Chronic Obstructive Pulmonary Disease (COPD)

Oxygen is important for cell metabolism and is critical for all wound-healing processes. Oxygen protects wounds from infection, encourages the formation of collateral circulation (angiogenesis) and ultimately promotes wound contraction. So any disease that limits the availability of oxygen is a cofactor in non-healing wounds.

COPD is a lung disease, often a mix of both chronic bronchitis and emphysema, that inhibits wound healing by reducing the quantity and quality of oxygen to the wound site.

Comorbidity #7: Paraplegia/Quadriplegia

Patients with spinal cord injuries or with paralysis in the lower extremities lack sensation, so messages regarding pain and the need to reposition do not travel to the brain for a response. As a result, these patients are prone to acquiring pressure sores that can worsen and become infected quickly.

Comorbidity #8: Aging

Elderly patients heal more slowly. Their skin is more fragile and their risk of infection is higher because of a slower inflammatory response, diminished antibody production and slower endocrine system function. In addition, elderly patients are more likely to have chronic diseases such as diabetes and heart disease that impair circulation and oxygenation.

Comorbidity #9: Poor Nutrition

Inadequate intake of nutrients or pre-existing malnutrition can delay healing or result in infection. And while most wounds heal regardless of nutritional status, severe protein-calorie malnutrition or specific nutritional deficits can impair healing.

For example, when the body is working to heal a wound, it needs up to three times the normal daily requirement of protein, along with additional calorie intake to make the necessary repairs. Adequate carbohydrate intake is equally important since without it, the body will break down protein to use for energy thereby diverting it from wound healing.

Additionally, taking in the correct amounts of vitamins A, C, and E, as well as zinc, iron, copper and manganese are all critical to efficient wound healing.

Comorbidity #10: Dementia, Alzheimer’s

Wound care patients with dementia have a decreased ability to participate in their own healing, depending on the extent of their condition. They may be unable or unwilling to comply with their physician’s treatments; or, they may be unable to adequately communicate with their healthcare providers.

Comorbidity #11: Emotional Disorders and Depression

Depression is also considered a comorbidity or cofactor in non-healing wounds. With major depression, patients can become non-compliant and resist performing the physical aspects of wound healing such as changing their dressings, keeping their wounds clean, taking their medicines and applying topical medications. In extreme cases, depression can cause the patient to miss wound care appointments and refuse treatment.

Wound healing is dependent on all the body’s systems functioning at peak performance, including the body’s ability to allocate and deliver sufficient energies and nutrients to the wound site. The body must also be able to transport the waste products, the dead cells and deoxygenated blood, away from the wound site during all the phases of wound healing in order to function efficiently. Generally speaking, any condition that interferes with those processes is considered a comorbidity to wound healing. A thorough patient history and assessment must be conducted to identify all cofactors that may may contributing to the delayed healing of a wound.

About the Author
Dr. Bruce Ruben is the Founder and Medical Director of Encompass HealthCare, located in West Bloomfield, Michigan. Encompass Healthcare is an outpatient facility featuring advanced wound care, IV antibiotic therapies, hyperbaric oxygen treatment, nutritional assessment, and other treatment modalities. Dr. Ruben is board certified in Internal Medicine, Infectious Disease, and in Undersea and Hyperbaric Medicine. He is a member of the Medical and Scientific Advisory Committee and National Spinal Cord Injury Association (NSCIA) board.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.