A reliability study of four validated diabetic foot ulcer classification systems

Abstract

Background: One of the many complications of diabetes mellitus is foot ulceration. Diabetic foot ulceration may have different presentations depending on the pathogenic contributing factor and this may lead to various outcomes. The need to classify, score and describe these lesions is needed for various reasons including clinical documentation and reporting. An agreed classification and scoring system in routine clinical care can improve documentation and communication between health care professionals, which may also improve the ease of discussion regarding potential outcomes at an early stage. Several classification systems have been devised in an attempt to address these requirements. Having a high inter-rater agreement between these classification systems can facilitate the logical approach to treating as well as predicting the outcome of diabetic foot ulceration. Aim: The aim of the study was to determine the inter-rater reliability between four validated classification systems in the grading/scoring of diabetic foot ulceration. Research Design and Method: A prospective non-experimental comparative study was held at the diabetes foot clinic at Mater Dei hospital. Patients with diabetes presenting with a new ulcer or long-standing ulcer were enrolled in this comparative study. Each ulcer was graded/scored by three experienced clinicians using four-classification systems; namely the University of Texas system, the SINBAD system, the Meggitt-Wagner system and the PEDIS system. These classifications were evaluated with score sheets at hand consisting of a description of each category. Results: All four classification systems had a satisfactory inter-rater agreement (p<0.05) when evaluated by three raters of various clinical experience, however, the strength of the agreement varied between classifications. The Meggitt-Wagner system had an almost perfect agreement, the SINBAD and UT systems had a strong inter-rater agreement whilst the PEDIS had a moderate inter-rater agreement. Conclusion The more complex the classification, the weaker the inter-rater agreement. Until a gold standard is reached, these classifications should not be used a single tool to predict ulcer outcome or determine treatment options. Such classifications should only be used in combination with other routine clinical assessments, to acquire an overall prognosis and manage appropriately to achieve the best possible outcome.