Matthew J Young

A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population

SummaryA cross-sectional multicentre study of randomly selected diabetic patients was performed using a standardised questionnaire and examination, to establish the prevalence of peripheral neuropathy in patients attending 118 hospital diabetes clinics in the UK. Vibration perception threshold was performed in two centres to compare with the clinical scoring systems. A total of 6487 diabetic patients were studied, 53.9% male, median age 59 years (range 18– 90 years), 37.4% Type 1 (insulin-dependent) diabetes mellitus, with a median duration of diabetes 8 years (0–62 years). The overall prevalence of neuropathy was 28.5% (27.4– 29.6 %) (95 % confidence interval) in this population. The prevalence in Type 1 diabetic patients was 22.7% (21.0– 24.4 %) and in Type 2 (non-insulin-dependent) diabetic patients it was 32.1 % (30.6–33.6 %). The prevalence of diabetic peripheral neuropathy increased with age, from 5% (3.1– 6.9 %) in the 20–29 year age group to 44.2 % (41.1–47.3 %) in the 70–79 year age group. Neuropathy was associated with duration of diabetes, and was present in 20.8 % (19.1–22.5 %) of patients with diabetes duration less than 5 years and in 36.8 % (34.9–38.7 %) of those with diabetes duration greater than 10 years. Mean vibration perception threshold measured at the great toe was 21.1±13.5 SD volts and correlated with the neuropathy disability score, r=0.8 p<0.001. In conclusion, diabetic peripheral neuropathy is a common complication associated with diabetes. It increases with both age and duration of diabetes, until it is present in more than 50% of Type 2 diabetic patients aged over 60 years. An increased awareness of the high prevalence of peripheral neuropathy, especially in older patients, should result in improved screening programmes in order to reduce the high incidence of neuropathic diabetic foot ulceration.

The risk of foot ulceration in diabetic patients with high foot pressure: a prospective study

SummaryFoot ulceration results in substantial morbidity amongst diabetic patients. We have studied prospectively the relationship between high foot pressures and foot ulceration using an optical pedobarograph. A series of 86 diabetic patients, mean age 53.3 (range 17–77) years, mean duration of diabetes 17.1 (range 1–36) years, were followed-up for a mean period of 30 (range 15–34) months. Clinical neuropathy was present in 58 (67%) patients at baseline examination. Mean peak foot pressure was higher at the follow-up compared to baseline (13.5 kg·cm−2±7.1 SD vs 11.2±5.4, p<0.001) with abnormally high foot pressures (>12.3) being present in 55 patients at follow-up and 43 at the baseline visit (p=NS). Plantar foot ulcers developed in 21 feet of 15 patients (17%), all of whom had abnormally high pressures at baseline; neuropathy was present in 14 patients at baseline. Non-plantar ulcers occurred in 8 (9%) patients. Thus, plantar ulceration occurred in 35% of diabetic patients with high foot pressures but in none of those with normal pressures. We have shown for the first time in a prospective study that high plantar foot pressures in diabetic patients are strongly predictive of subsequent plantar ulceration, especially in the presence of neuropathy.

The Prediction of Diabetic Neuropathic Foot Ulceration Using Vibration Perception Thresholds: A prospective study

OBJECTIVE To assess the ability of vibration perception threshold (VPT) to predict the development of diabetic foot ulceration. RESEARCH DESIGN AND METHODS A prospective follow-up study of consecutive patients with vibration perception measured by biothesiometry from April 1988 to March 1989. Patients were stratified in various risk groups. RESULTS Patients with a VPT <15 V had a cumulative incidence of foot ulceration of 2.9% compared with 19.8% in patients with a VPT >25 V, odds ratio (OR) 7.99 (3.65–17.5, 95% confidence intervals), P < 0.01. The incidence of ulceration increased with duration of diabetes, but even with this effect removed, the excess of ulceration persisted, OR 6.82 (2.75–16.92), P < 0.01. CONCLUSIONS VPT is an effective predictor of the risk of foot ulceration in diabetes and therefore could be used to target foot-care education to those patients most likely to benefit and, thereby, possibly improve its effectiveness.

The association between callus formation, high pressures and neuropathy in diabetic foot ulceration

The presence of an ulcer beneath callus on the diabetic foot has been a well‐documented and common clinical finding. We have conducted a prospective study to examine whether callus can be used to predict plantar intrinsic neuropathic diabetic foot ulcer formation. Sixty‐three diabetic patients (43 male, 25 Type 1), median age 62 years (IQ range 52, 67), median diabetes duration 17 years (IQ range 8,25) participated in the study. All had neuropathy and peak plantar foot pressures (measured using a dynamic optical pedobarograph) ⩾10 kg cm−2. Calluses and previous ulcers were documented and classified. All ulcers occurring prior to and during the study were recorded, re‐examination was 15.4 (range 10–22) months from baseline. Seven ulcers (6 patients) occurred during the study. Pressures were higher in the ulcer than non‐ulcer sub‐group (p = 0.04) with a relative risk of developing an ulcer of 4.7 for an area of elevated plantar pressure. This compares with a relative risk of 11.0 for an ulcer developing under an area of callus, and a relative risk of 56.8 for an ulcer developing on a site of previous ulceration. This study confirms that a history of previous ulceration is the highest risk factor for ulceration and demonstrates, for the first time, that the presence of plantar callus is highly predictive of subsequent ulceration. Careful history taking and examination of the foot to detect the presence of callus require no special training or equipment and callus should be recognized as a ‘high risk’ factor for foot ulceration.

Semmes-Weinstein monofilaments: a simple, effective and inexpensive screening device for identifying diabetic patients at risk of foot ulceration.

Both vibration perception threshold (VPT) by biothesiometry and pressure perception using Semmes-Weinstein monofilaments (filaments) have been proposed to identify diabetic patients at risk of foot ulceration. The two methods were compared in 182 subjects attending a national patients conference. Both measures were made over the great toe. Filaments of three calibres were used: 4.17, 5.07 and 6.10 bending with 1, 10 and 75 g force, respectively. Pressure perception was normal (4.17) in 122 patients (group 1) whereas in 45 patients it was grade 5.07 (group 2) and 6.10 or greater in 15 (group 3). The corresponding mean VPT (+/- SD) for the three groups were 10.6 (+/- 6.7), 22.8 (+/- 12.7) and 32 (+/- 14.3), respectively. The mean VPT for the 3 groups were significantly different (P less than 0.001). The filaments were more sensitive (100%) but less specific (77.7%) in identifying patients who had foot ulcers compared to biothesiometry which was less sensitive (78.6%) but more specific (93.4%). The filaments are therefore reliable and may be superior to biothesiometry in screening for patients at risk of foot ulceration since sensitivity is the more important parameter. In addition, they are inexpensive (12 pounds) compared to the biothesiometer (400 pounds) and are simple and easy to use.

The effect of callus removal on dynamic plantar foot pressures in diabetic patients.

Clinical observation suggests that neuropathic foot ulceration frequently occurs beneath plantar callosities and in areas of high dynamic shear and vertical stress underneath the foot during walking. Seventeen diabetic patients had dynamic foot pressure measurements made before and after the removal of a total of 43 forefoot plantar callosities. Peak pressures (mean ± SE) in the treated areas were reduced by 26% from 14.2 ± 1.0 to 10.3 ± 0.9 kg cm−2 (p < 0.001), with reductions at 37 of the 43 sites and in all patients. Mean heel pressures were not significantly different (5.0 ± 0.6 vs 4.9 ± 0.6 kg cm−2). These results suggest that callus may act as a foreign body elevating plantar pressures and that a significant reduction in pressure is achieved by local chiropody treatment.

Medial arterial calcification in the feet of diabetic patients and matched non-diabetic control subjects

SummaryThe prevalence and distribution of medial arterial calcification was assessed in the feet of four subject groups; 54 neuropathic diabetic patients with previous foot ulceration (U), median age 60.5 (50.5–67 interquartile range) years, duration of diabetes 19.5 (9.9–29.9) years; 40 neuropathic diabetic patients without a foot ulcer history (N), age 68 (62–73) years, duration of diabetes 14.0 (8.0–28.0) years; 43 non-neuropathic diabetic patients (NN), age 60.5 (52–68.5) years, duration of diabetes 14.0 (8.0–28.0) years and 50 non-diabetic control subjects, age 62.5 (53.7–70) years. A single radiologist graded medial arterial calcification as absent, mild or severe, at the ankle, hind-foot, mid-foot, metatarsals and toes on standardised plain lateral and antero-posterior foot radiographs taken by a single radiographer. Diabetes history, vibration perception threshold, ankle systolic pressure and serum creatinine were also assessed. Medial arterial calcification was significantly greater (total score 18 [3–31]) in neuropathic diabetic patients with previous ulceration (U vs N p<0.01, U vs NN p<0.001). Non-neuropathic diabetic patients did not have significantly higher arterial calcification scores than age-matched non-diabetic control subjects. Medial arterial calcification correlated with vibration perception threshold (r=0.35), duration of diabetes (r=0.32) and serum creatinine (r=0.41), (all p<0.01). Logistic regression models showed vibration perception and duration of diabetes to predict the probability of any calcification. Serum creatinine level was added to predict severe calcification. Ordered categorical modelling confirmed that medial arterial calcification was significantly heavier at the ankle than the toes for all groups, odds ratio 4.35 (2.94–6.43, 95% confidence intervals), (p<0.01). Ankle systolic pressure and ankle-brachial pressure index were significantly associated with degree of arterial calcification, r=0.40 and r=0.35, respectively, (both p<0.01) in diabetic patients. However, arterial calcification was present in more than one-third of patients with an ankle-brachial pressure index of less than 1.0. In conclusion, although ankle pressures correlate with the degree of arterial calcification, medial arterial calcification may be present in patients with low ankle systolic pressures, which may be falsely elevated even at ‘normal’ values. This finding may provide a rationale for the use of toe rather than ankle pressure measurements in diabetic patients, particularly those with peripheral neuropathy, and this hypothesis should be directly tested in future studies.

Osteopenia, Neurological Dysfunction, and the Development of Charcot Neuroarthropathy

OBJECTIVE To determine factors that might be associated with the development of Charcot neuroarthropathy. RESEARCH DESIGN AND METHODS This cross-sectional prevalence study examined neurological function and bone density in matched groups of neuropathic diabetic patients with and without radiological evidence of Charcot neuroarthropathy. RESULTS Patients with Charcot neuroarthropathy had a global impairment of neurological function that was significantly greater than that of otherwise matched non-Charcot neuropathic patients. All 17 Charcot patients had evidence of autonomic neuropathy compared with 10 of the control subjects (P = 0.03). The Charcot patients had evidence of reduced bone density in the lower limbs compared with the neuropathic control subjects (P = 0.009), but relatively preserved bone density in the spine (P = 0.4 vs. control subjects). CONCLUSIONS We conclude that minor trauma in diabetic patients with peripheral neuropathy might result in a fracture in those with a reduced bone density and thus trigger the development of Charcot neuroarthropathy.

Radiographic Abnormalities in the Feet of Patients With Diabetic Neuropathy

OBJECTIVE To investigate the prevalence of radiographie bone and joint abnormalities in the feet of diabetic patients. RESEARCH DESIGN AND METHODS In a blinded randomized study, 94 diabetic patients with peripheral neuropathy (54 with a history of foot ulcers) and 43 non-neuropathic patients were drawn at random from the data base of a large university diabetes clinic in the United Kingdom. Fifty nondiabetic age-matched control subjects also were studied. Lateral and dorsi-plantar weight-bearing plain radiographs of the foot and ankle were taken by a single radiographer. Abnormalities in the bones and joints were determined according to a structured reading of the radiographs by a single radiologist. RESULTS Diabetes per se resulted in no excess of bony abnormality. Diabetic patients with neuropathy had significantly more radiographic abnormalities of the bones and joints than non-neuropathic and age-matched nondiabetic control subjects. However, except for periosteal reaction, this was predominantly caused by an excess of abnormalities in diabetic patients with a history of foot ulceration. Traumatic fractures (most previously unrecognized) were found in 12 (22%) of the 54 neuropathic patients with previous foot ulceration, and 9 (16%) patients who had experienced foot ulcers exhibited characteristic Charcot changes. CONCLUSIONS These results suggest that bony abnormalities, particularly Charcot changes and traumatic fractures, are more frequent than previously recognized in neuropathic diabetic patients, especially in those with a history of foot ulceration. Early recognition of bony abnormality and appropriate treatment may prevent progression of foot deformity and thereby reduce the morbidity caused by ulceration or reulceration.

Improved survival of diabetic foot ulcer patients 1995-2008, possible impact of aggressive cardiovascular risk management

OBJECTIVE—The purpose of this study was to determine whether a strategy of aggressive cardiovascular risk management reduced the mortality associated with diabetic foot ulceration. RESEARCH DESIGN AND METHODS—After an initial audit of outcomes demonstrating a high mortality rate in 404 diabetic foot ulcer patients with the first ulceration developing between 1995 and 1999, a new aggressive cardiovascular risk policy was introduced as standard practice at the Diabetic Foot Clinic, Royal Infirmary of Edinburgh, in 2001. In the first 3 years of this policy, 251 patients were screened and identified. The audit cycle was then closed by reauditing the 5-year mortality for this second group of foot ulcer patients in 2008. RESULTS—Overall 5-year mortality was reduced from 48.0% in cohort 1 to 26.8% in cohort 2 (P < 0.001). Improvement in survival was seen for both neuroischemic patients (5-year mortality of 58% reduced to 36%; relative reduction 38%) and neuropathic patients (36% reduction to 19%; relative reduction 47%) (both P < 0.001). Patients were more likely to die if they were older at the time of ulceration or had type 2 diabetes, renal impairment, or preexisting cardiovascular disease or were already taking aspirin. Prior statin use, current smoker or ex-smoker status, blood pressure, A1C, and total cholesterol were not significantly different between survivors and those who died in the follow-up periods. CONCLUSIONS—Diabetic foot ulcer patients have a high risk of death. Survival has improved over the past 13 years. The adoption of an aggressive cardiovascular risk management policy in diabetic foot ulcer clinics is recommended for these patients.