Is an ulcer on the lower extremities in a patient with diabetes (DM) and vascular insufficiency classified as a diabetic foot ulcer or a vascular ulcer?

Classification of Lower Extremity Ulcers in Patients with Both Diabetes and Vascular Insufficiency

An ulcer in a patient with both diabetes and vascular insufficiency should be classified as a diabetic foot ulcer with peripheral artery disease (PAD), not simply as a "vascular ulcer," because the presence of diabetes fundamentally changes the pathophysiology, prognosis, and management approach. 1

Why This Matters for Classification

The IWGDF (International Working Group on the Diabetic Foot) 2023 guidelines explicitly address this scenario and recommend using classification systems that account for both the diabetic and vascular components simultaneously. 1

Key Classification Principle

• Up to 50% of patients with diabetes and foot ulcers have concomitant PAD, making this a common clinical scenario rather than an exception. 1
• The concomitant presence of infection and PAD in a diabetic foot ulcer has an incremental effect on risk of poor outcomes including non-healing, delayed healing, and amputation. 1
• Studies validating classification systems have clearly demonstrated that PAD in diabetic foot ulcers creates worse outcomes than either condition alone. 1

Recommended Classification Systems

Primary Recommendation: WIfI System

When resources and vascular surgery expertise are available, use the WIfI (Wound, Ischemia, and foot Infection) classification system. 1

The WIfI system specifically grades three components:

• Wound Grade (0-3): Based on ulcer depth, tissue loss, and gangrene extent 1
• Ischemia Grade (0-3): Based on ABI, ankle systolic pressure, and toe pressure/TcPO2 measurements 1
• Foot Infection Grade (0-3): Based on clinical manifestations of infection 1

This system provides a direct link to clinical management and stratifies both healing likelihood and amputation risk. 1

Alternative: IDSA/IWGDF Classification for Infection

If equipment for comprehensive vascular assessment is unavailable, or when primarily assessing infection severity, use the IDSA/IWGDF infection classification system. 1

This grades infection from 1-4 (uninfected to severe systemic infection) and can stand alone when vascular assessment tools are limited. 1

Critical Diagnostic Requirements

Mandatory Vascular Assessment

Every patient with diabetes and a foot ulcer must have vascular status evaluated—this is non-negotiable. 1

Perform immediately:

• History for claudication or rest pain 1
• Palpation of dorsalis pedis and posterior tibial pulses 1
• Hand-held Doppler evaluation of both foot arteries 1
• Ankle-brachial index (ABI) measurement 1
• Toe pressure or TcPO2 if diagnostic uncertainty exists 1

Interpreting Vascular Measurements

PAD is present when:

• ABI <0.9 1, 2, 3
• ABI <0.6 indicates significant ischemia affecting wound healing potential 1
• ABI <0.5 or ankle pressure <50 mmHg indicates severe ischemia requiring urgent vascular imaging 4, 2, 3
• Toe pressure <30 mmHg or TcPO2 <25 mmHg mandates urgent revascularization consideration 4, 2

Critical Pitfall: Arterial calcification in diabetes can cause falsely elevated ABI readings; always correlate with pulse examination and consider toe pressures when ABI seems inconsistent with clinical findings. 3

Why "Vascular Ulcer" Alone Is Inadequate

Classifying this simply as a "vascular ulcer" ignores:

1. Diabetic neuropathy's contribution to foot deformity, callus formation, and insensitivity to trauma 5, 6, 7
2. Different treatment algorithms required for diabetic foot ulcers versus non-diabetic vascular ulcers 1
3. Higher amputation risk when diabetes and PAD coexist 1, 7
4. Need for glycemic control as part of wound management 2, 6
5. Specific offloading requirements unique to diabetic foot ulcers 4

Practical Management Implications

Once classified as a diabetic foot ulcer with PAD:

• Immediate sharp surgical debridement of necrotic tissue (unless severe ischemia without infection) 4, 2
• Urgent vascular imaging if toe pressure <30 mmHg, TcPO2 <25 mmHg, or ABI <0.5 4, 2
• Revascularization goal: Restore direct blood flow to achieve minimum toe pressure ≥30 mmHg or TcPO2 ≥25 mmHg 4, 2
• Aggressive cardiovascular risk reduction including statin therapy, antiplatelet agents, and blood pressure control 4, 2
• Pressure offloading with appropriate footwear modifications 4
• If no improvement within 6 weeks despite optimal care, proceed to vascular imaging and revascularization regardless of initial bedside test results 4, 2, 3