Part 6: Detection and Prevention of Foot Problems in Type 2 Diabetes

Background - Peripheral Neuropathy as a Risk FactorFifteen percent of people with diabetes will develop a foot ulcer during their lifetime(Reiber et al, 1998). Half of all non-traumatic amputations are performed in peoplewith diabetes (Pecoraro et al, 1990). Foot ulcers precede 84% of all lower limbamputations in diabetic people in the United States (Pecoraro et al, 1990). While thecause of ulceration is multifactorial, understanding the main factors in the aetiology ofthe ulcer will increase the likelihood of reducing ulceration and amputation despitethe rising prevalence of diabetes.In the UKPDS study damage to the peripheral nerves from prolonged hyperglycaemiaand its metabolic consequences was present in 12.3% at diagnosis and in 30% after 12years of diabetes (UKPDS 33, 1998). The commonest form is a distal symmetricalpolyneuropathy with a glove and stocking distribution of loss of sensation. Howeverthe loss of protective sensation is postulated to be the major factor in subsequentulceration. Coexistence of autonomic neuropathy can contribute partly by inducingdry skin and foot oedema (Boyko et al, 1999). Muscle wasting and foot deformityresulting from peripheral neuropathy are also thought to contribute to the risk ofulceration. Severe peripheral neuropathy can lead to joint disorganisation fromrepeated trauma with loss of protective sensation resulting in a Charcot joint (mostfrequently the tarsometatarsal joint). The resulting foot disorganisation and deformitycontribute to recurrent ulceration (Sims et al, 1988). However it is also clear thatprecipitating factors are also necessary for the development of diabetic foot ulcers.Knowing the relative risk of peripheral neuropathy as an underlying risk factor forulceration and amputation can help in targeting those with diabetes who are at riskand implementing preventative interventions to reduce subsequent ulceration andamputation (Shaw & Boulton, 1997).Evidence - Peripheral Neuropathy as a Risk FactorPeripheral neuropathy is associated with diabetic foot ulceration and amputationSeveral studies in people with Type 2 diabetes have related reduction of foot sensationand risk of ulceration or amputation.Coppini et al (1998) reported the incidence of foot ulcers or amputations in 405subjects without prior amputation attending St Thomas’ Hospital Diabetic Clinic. Therecords were examined retrospectively, and 20 people who developed foot ulcer oramputation over the 14 year follow-up period were each matched with 3 peoplewithout ulcers. The population was 60% males with cases being of similar mean ageto the controls (50.5 v 50.1 years) however they had a much longer duration ofdiabetes (9.7 v 4.1 years, p=0.02). A raised VPT at baseline was a predictor of footcomplications developing with OR 4.38 (CI 1.1-17.26, p=0.01).In 811 people with Type 2 diabetes in a community based cross-sectional study from37 UK general practices, neuropathy was diagnosed by clinical scoring. Thepopulation was 50% males with a mean age of 65.4 years (range 34-90 years) and hada duration of diabetes of 7.4 years (range 0-50 years). Those with neuropathy were12