Grading Diabetic Foot Ulcers
Use the SINBAD classification system for communication among healthcare professionals, describing individual variables rather than a total score, or alternatively consider the WIfI system when specialized equipment and expertise are available. 1
Significance of Grading Diabetic Foot Ulcers
Grading diabetic foot ulcers is critical because it directly impacts patient outcomes including amputation risk, wound healing, hospitalization, and survival. 1 The classification serves multiple essential clinical purposes:
Key Clinical Applications
- Communication between healthcare professionals: Facilitates referral and ensures consistent information transfer across care settings 1
- Guiding management decisions: Helps determine appropriate interventions based on ulcer characteristics 1
- Population audit: Enables comparison of outcomes between institutions and tracking of care quality 1
However, no existing classification system should be used to predict individual patient outcomes - the evidence quality is too weak and likelihood ratios are insufficient (positive likelihood ratios <5, negative likelihood ratios 0.2-0.4) to meaningfully change pre-test to post-test probability. 1
How to Grade Diabetic Foot Ulcers
Primary Recommendation: SINBAD System
For routine clinical communication and population audit, use the SINBAD classification, which grades six key features: 1
- Site: Location of the ulcer
- Ischaemia: Presence of peripheral artery disease
- Neuropathy: Loss of protective sensation
- Bacterial infection: Presence and severity of infection
- Area: Size of the ulcer
- Depth: Tissue layers involved
Critical caveat: Report the individual variables that compose the system rather than calculating a total score, as this provides more clinically useful information. 1
Alternative Option: WIfI System
Consider the WIfI (Wound, Ischaemia, foot Infection) system when: 1
- Required equipment for vascular assessment is available
- Appropriate level of clinical expertise exists
- The setting makes it feasible to perform detailed vascular evaluation
The WIfI system grades three domains: 1
- Wound: Extent of tissue loss (grades 0-3, from no ulcer to extensive deep ulcer)
- Ischaemia: Severity of arterial insufficiency (requires ankle-brachial index, toe pressures, or transcutaneous oxygen measurements)
- Infection: Presence and severity of infection
Specific Clinical Scenarios
For infected ulcers specifically: Use the IDSA/IWGDF infection classification as first-line, or consider WIfI as an alternative when resources permit. 1
For ulcers with peripheral artery disease: Consider WIfI system to stratify healing likelihood and amputation risk, as it was specifically designed to assess limb threat in the context of vascular disease. 1
Critical Outcomes That Drive Classification Choice
The IWGDF prioritized these outcomes when evaluating classification systems: 1
- Lower extremity amputation: Major determinant of long-term morbidity
- Wound healing: Primary treatment goal
- Hospitalization: Resource utilization and complication indicator
- Survival: Ultimate patient outcome
- Health-related quality of life: Patient-centered outcome measure
Common Pitfalls to Avoid
Do not use classification systems to predict individual patient prognosis - despite their utility for communication and audit, existing systems lack sufficient accuracy for individual outcome prediction. 1
Do not rely solely on total scores - the individual components (area, depth, ischemia, infection) provide more actionable clinical information than composite scores. 1
Recognize that validation varies globally - classification system performance differs based on population characteristics, local context, and available healthcare resources, so systems validated in high-resource settings may not perform identically elsewhere. 1