Epidemiology of foot ulceration and amputation: can global variation be explained?

Amputation is a treatment, and not simply part of the natural history of foot disease. However, assessment of amputation incidence is the measure most frequently used to document an outcome reflecting the management of diabetic foot disease, mainly because the data are already captured in most health care systems. Nevertheless, interpretation of the results requires great care. Many centers have recorded decreases in the incidence of amputation in recent years and have concluded that this reflects improvement in clinical care. Although improvement in clinical care is clearly of a priority, it is important not to underestimate the extent to which the at-risk population (those with diabetes) may have changed as a result of changing criteria for the diagnosis of diabetes, as well as the increasing implementation of systematic and opportunistic screening. The incidence of amputation can be calculated and expressed in many ways, with different groups using different criteria for deciding both the numerator and the denominator, and studying populations that may differ in several different ways. Given that the incidence of amputation can also be influenced by a wide variety of clinical and social factors, it is not surprising that considerable variation exists between published studies from different countries. For these reasons it is currently difficult to make meaningful comparisons between data from different countries. On the other hand, the demonstration of wide variation within a single country or between countries or communities that have very similar populations, health care systems, and procedures for documenting amputation incidence is of greater interest. When 8- to 10-fold variation exists within similar health care systems, a risk as large as any published risk factor for amputation, it is essential that the reasons are explored. While race and social deprivation both make an important contribution to variation, another is likely to relate to aspects of the structure of care, including the training and beliefs of individual clinicians, patients’ access to care, preferences of patients, and the ability of a patient to understand the need for care and execute a care plan. This area of study requires further investigation.