Assessment of diabetic foot ulcers based on pictorial material: an interobserver study

The frequent change in clinicians, and the emerging use of photographic documentation in wound management, could require a more diverse treatment of patients due to poor interobserver agreement. The aim of this study was to assess the interobserver agreement of a commonly used classification system for diabetic foot ulcers (DFUs), the Meggitt-Wagner classification, and to compare the agreement on classification with the agreement in treatment recommendations.

An interobserver study was conducted based on a questionnaire linked to 30 photographs of DFUs. Different groups of observers were tested to investigate whether there was a difference between professions or level of education: experienced orthopaedic wound care doctors (n=7); nurses specialised in wound care (n=8) and untrained nurses assigned to a diabetic wound care training course (n=23). Krippendorff's alpha was used to calculate interobserver agreement, and an agreement of >0.67 was defined as substantial.

The Krippendorff's alpha value for interobserver agreement on the Meggitt-Wagner classification was 0.52 for the doctors group, 0.67 for the specialised nurses and 0.61 for the untrained nurses. The corresponding values regarding agreement on recommendation of surgical revision of the wound were 0.35, 0.22 and 0.15, respectively. The choice of dressing type or antibiotic treatment had even lower interobserver agreement.

The interobserver agreement on the Meggitt-Wagner classification was substantial in the specialised nurse group, but the evaluation and treatment of DFUs should not be exclusively based on pictorial materials.