From the Guidelines
High hemoglobin A1C (HbA1C) levels significantly impair wound healing by causing multiple physiological disruptions, and for optimal wound healing, patients should aim for HbA1C levels below 7%. Elevated HbA1C, which indicates poor glycemic control over the previous 2-3 months, leads to reduced blood flow to tissues due to vascular damage, impaired immune function with decreased white blood cell activity, and collagen cross-linking that weakens tissue structure 1. The hyperglycemic environment promotes bacterial growth while diminishing neutrophil function, increasing infection risk. Additionally, high blood sugar causes oxidative stress and inflammation that further delay healing. Nerve damage from prolonged hyperglycemia may prevent patients from noticing wounds, allowing them to worsen undetected.
Some key points to consider in wound healing for patients with high HbA1C levels include:
- Offloading of plantar ulcerations
- Debridement of necrotic, nonviable tissue
- Revascularization of ischemic wounds when necessary
- Management of infection: soft tissue or bone
- Use of physiologic, topical dressings 1
- Advanced wound therapy can be considered if a wound fails to show a reduction of 50% or more after 4 weeks of appropriate wound management 1
For optimal wound healing, consistent blood glucose monitoring and management through appropriate medication (such as insulin, metformin, or other diabetes medications as prescribed), proper nutrition with controlled carbohydrate intake, regular exercise, and diligent wound care including keeping the area clean, moist, and protected are essential 1. Addressing high HbA1C is crucial because even a 1% reduction can significantly improve healing outcomes and reduce complications like chronic ulcers or amputations.
It is also important to assess the affected limb and foot for arterial ischemia, venous insufficiency, and other factors, and to evaluate the foot for deformities such as Charcot arthropathy, claw or hammer toes, bunions, or callosities 1. The presence of systemic signs or symptoms generally signifies severe infection with extensive tissue involvement or more virulent pathogens, and elevated inflammatory markers have been shown to predict worse clinical outcomes of treatment 1.
Overall, managing high HbA1C levels is critical for optimal wound healing, and a multidisciplinary approach to wound care is often necessary to achieve the best outcomes 1.
From the Research
Effects of High A1C on Wound Healing
- A high Hemoglobin A1C (HbA1C) level can impede the wound healing process, as evidenced by a study published in The Journal of investigative dermatology 2, which found that for each 1.0% point increase in HbA1C, the daily wound-area healing rate decreased by 0.028 cm(2) per day.
- The healing process can be affected by the level of glycemia, as assessed by HbA1C, which may be an important biomarker in predicting wound-healing rate in diabetic patients 2.
- Another study published in The Journal of surgical research 3 found that diabetes-induced impairment of wound healing may be due to a deficiency in growth factor activity within the wound environment, including reduced levels of transforming growth factor-beta and insulin-like growth factor-I.
Factors Influencing Wound Healing
- Diabetes mellitus is a significant risk factor that impedes the healing process, along with other factors such as advanced age, compromised immunocompetence, inadequate perfusion, and oxygenation, infection, malnutrition, obesity, and preoperative illness 4.
- Obesity has been shown to impair wound healing, and chronic nonhealing wounds in obesity and diabetes are a major cause of limb amputations 5.
- Exercise has been found to speed healing in both aged and obese mice and in older adults, and may be a useful intervention strategy to prevent or treat impairments in the wound-healing process 5.
Association between HbA1C and Wound Healing
- A study published in Diabetes care 6 found that baseline HbA1C was not associated with wound healing in univariate or fully adjusted models, but a nadir HbA1C change of 0.09 to 2.4 was positively associated with long-term wound healing in the subset of participants with baseline HbA1C <7.5%.
- However, another study 2 suggests that HbA1C may be an important biomarker in predicting wound-healing rate in diabetic patients, highlighting the need for further research to fully understand the relationship between HbA1C and wound healing.