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

Background - Clinical Detection of Peripheral Vascular DiseasePeripheral vascular disease (PVD) is common in people with Type 2 diabetes beingpresent in 8% at the time of diagnosis and in 45% of people who have had diabetes for20 years (Hiatt & Sussman, 1994). The prevalence of PVD at diagnosis of diabetesand the risk of developing PVD over time increase with increasing age (Davis et al,1997). As reviewed in Section 2, PVD is an important risk factor for amputation.Although various factors predict the outcome of foot ulcers in people with diabetes,the severity of existing lower extremity arterial disease is considered to be the mainindependent risk factor for major amputation (Pecoraro et al, 1990).While sophisticated and invasive tests are now available to quantify the extent of PVDin people with diabetes, clinical means of identifying those with PVD remainimportant in the primary care setting. A history of intermittent claudication is a wellrecognised feature of PVD. Claudication pain arises in an exercising muscle when theperfusion pressure of the blood during exercise is insufficient to remove anaerobicmetabolites and maintain muscle function. In contrast to those without diabetes, thearteries below the knee are more severely affected in people with diabetes (LoGerfo &Coffman, 1984). Exercise-induced leg pain most commonly begins in the calf but canextend to the thigh or buttocks if exercise is continued. Severe claudication is mostoften the result of multilevel arterial disease.Palpation of foot pulses is a routine part of the assessment of the peripheral circulationin people with diabetes. Pedal pulse palpation is a simple and adequately reliableclinical method (Meade et al, 1968). Other clinical signs which may be useful includeatrophic skin and loss of hair, pallor on elevation followed by dusky colour ondependency and a prolonged capillary filling time.Several studies have reported that clinical signs of PVD correlate well with future riskof amputation although it should be remembered that the absence of claudication doesnot exclude a diagnosis of PVD since pain may not be a feature if peripheralneuropathy is also present. Also some of the controversy about the usefulness ofroutine clinical examination of peripheral pulses is in part related to inter-observervariation and a relatively high false-positive rate for the presence of PVD.Evidence - Clinical Detection of Peripheral Vascular DiseaseIntermittent claudication is indicative of peripheral vascular diseaseA cross-sectional study in 631 predominantly male veterans (mean age 63.4 years)with diabetes in a general medical clinic compared the accuracy of data from historyand physical examination on the detection of severe PVD, assessed by an ankle-armindex (AAI) ≤0.5 using Doppler blood pressure measurements (Boyko et al, 1997).The study showed that 46 people had severe PVD (AAI ≤0.5) in the right leg, 44 inthe left leg, and 26 in both legs. Claudication symptoms had a sensitivity of 50% anda specificity of 87% for PVD by AAI, compared with 65% and 78% for absent ordiminished peripheral pulses and 22% and 93% for venous filling time >20 seconds.A stepwise logistic regression model identified age, symptom of claudication, selfreportedhistory of PVD, absent or diminished peripheral pulses and prolonged48