Guidelines for diagnosis and outpatient management of diabetic peripheral neuropathy. European Association for the Study of Diabetes, Neurodiab

Diabetic peripheral neuropathy is estimated to affect at least 30% of patients with diabetes mellitus. The appropriate management of this disturbance is essential if late-stage complications, such as foot ulceration and amputations, are to be avoided in these patients. The need for improvements in the clinical management of neuropathy in primary and outpatient hospital care resulted in the identification of an international consensus group to address the management of diabetic peripheral neuropathy by the practising clinician. The international consensus group included diabetologists, neurologists, primary care clinicians, diabetes specialist nurses and podiatrists. The outcome of this consensus group was endorsed by the Neurodiab Executive Committee. The International Guidelines describe the recommendations for the management of diabetes in primary care and in outpatient hospital care and include an annual review of diabetic patients. This should include a history of patient symptoms, the type of diabetes, lifestyle and social circumstances. In examination of the foot, the status of the skin (e.g. absence of sweating and presence of ulceration) immobility of joints, gait and footwear should be noted. Simple tests should be performed to assess peripheral sensation, including sensation to pinprick, light touch, vibration, pressure, and ankle reflexes should be checked. It is the objective of the guidelines document to provide clear and simple instructions for the diagnosis and management of neuropathy on an outpatient basis, in particular during annual review of the patient. Adoption of the guidelines should lead to improvements in the management of neuropathy.

An analysis of dynamic forces transmitted through the foot in diabetic neuropathy

OBJECTIVE

Biomechanical studies in diabetic neuropathy have clearly demonstrated abnormal foot pressures, but information on other aspects of gait is limited. This study aimed to investigate and describe the forces transmitted through the foot during walking in diabetic subjects with varying degrees of peripheral neuropathy and to determine if abnormalities in these forces might contribute to the risk of plantar ulceration.

RESEARCH DESIGN AND METHODS

Subjects from the following groups were included: healthy control subjects (C); diabetic control subjects (D); subjects with diabetic neuropathy (DN); subjects with previous neuropathic ulceration (DNU); and subjects with Charcot neuro-arthropathy (CH). Gait analysis was performed as subjects walked over a Kistler force plate. Peak forces were measured (as percent body weight) in the vertical and horizontal planes. Comparisons were made between all of the groups and between each diabetic group and a healthy control group matched for walking speed.

RESULTS

There were 181 subjects studied. In comparison with that of the speed-matched controls, the mean peak vertical force was higher in each of the diabetic groups, especially in the most neuropathic subjects (DNU, 113 vs. 110%, P < 0.01). This increase was entirely due to higher forces during heel contact (DNU, 111 vs. 106%, P < 0.001). The single peak force occurred during heel strike (rather than during foot push-off) in 23-38% of footsteps of healthy and diabetic control subjects but in 53-73% of footsteps of neuropathic subjects. There was also a trend for higher peak medial forces (CH, 6.2 vs. 5.5%, P < 0.05).

CONCLUSIONS

Diabetic neuropathy is associated with a change in the time pattern of the forces transmitted through the foot and an increase in the vertical forces through the heel. The magnitude of the changes is small in absolute terms, but these changes may contribute to the risk of plantar foot ulceration.

Serum paraoxonase (PON1) 55 and 192 polymorphism and paraoxonase activity and concentration in non-insulin dependent diabetes mellitus

Human serum paraoxonase (PON1) is located on high density lipoprotein and has been implicated in the detoxification of organophosphates and possibly in the prevention of low density lipoprotein lipid peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine (A genotype) and arginine (B genotype) at position 192 and the other leucine (L genotype) and methionine (M genotype) at position 55. We investigated the effect of these polymorphisms on serum PON1 activity and concentration in 252 non-insulin dependent diabetes mellitus (NIDDM) individuals and 282 non-diabetic controls. Serum PON1 activity in the controls (214.6 nmol/min per ml (26.3-620.8)) was significantly higher than in NIDDM (158.7 nmol/min per ml (3.6-550.5) (P < 0.001) as was serum PON1 concentration (89.1 microg/ml (16.8-527.4)) compared to 76.7 microg/ml (3.6-443.8) (P < 0.01). In the control population MM homozygotes had significantly lower serum PON1 activity regardless of the 192 polymorphism whereas in NIDDM both LM and MM genotypes had lower serum PON1 activity than LL homozygotes only when the 192 AA genotype was present. Serum PON1 concentration was lower in NIDDM with AA/LM, AA/LL, AB/LL and AB/MM genotypes than in controls. Differences in PON1 activity were the major cause of differences in specific activity between genotypes. Neither the PON1 55 or 192 polymorphisms consistently influenced the serum lipid or lipoprotein concentrations in either population. Low serum PON1 activity in NIDDM may be related to an increased tendency to lipid peroxidation and may also increase susceptibility to toxicity from organophosphate exposure. Our findings thus raise the possibility that PON1 may be of importance in both the genetic and acquired predisposition to premature atherosclerosis and neuropathy in diabetes.

Multicenter study of the incidence of and predictive risk factors for diabetic neuropathic foot ulceration

OBJECTIVE

To investigate longitudinally prognostic factors for foot ulceration in a large population of diabetic patients with established neuropathy.

RESEARCH DESIGN AND METHODS

A double-blind multicenter study of a potential new agent for diabetic neuropathy provided the opportunity for this 1-year investigation since intervention demonstrated no efficacy in the condition. A total of 1,035 patients with NIDDM and IDDM were included. Inclusion criteria were vibration perception threshold (VPT) at the great toe > or = 25 V in at least one foot and < or = 50 V in both feet, normal peripheral circulation, and no previous foot ulceration. VPT and clinical components of the Michigan diabetic polyneuropathy (DPN) score were assessed at baseline and subsequent visits.

RESULTS

After 1 year, the incidence of first foot ulcers for the total population was 7.2%. Neuropathy parameters were the same between the treatment and placebo groups at baseline and were unchanged at 1 year; therefore, baseline data were combined for multiple regression analysis. VPT, age, and Michigan DPN scores for muscle strength and reflexes were significant independent predictors for first foot ulceration (P < 0.01). For each 1-U increase in VPT values at baseline, the hazard of the first foot ulcer increased by 5.6%. Similarly, for each 1-U increase in muscle strength and reflex components of the Michigan DPN scores, the hazard of the first foot ulcer increased by 5.0%.

CONCLUSIONS

Tests of VPT and Michigan DPN scores for muscle strength and reflexes are useful clinical predictors for foot ulceration in diabetic patients with established neuropathy. The rate of subsequent ulceration in the following year was alarmingly high, however, despite standardized foot care education at baseline and regular follow-up visits.

Diabetic neuropathy

Better clinical characteristics and a standardized approach to the definition of neuropathy has enabled us to define more precisely the natural history of diabetic neuropathy. Detailed studies on the pathology and pathogenesis have allowed dissection of important pathogenetic pathways. Effective treatment is currently limited, although a number of new and potentially important therapeutic interventions, including modification of the vascular supply and antioxidant status and growth factors, may prove to be of benefit in preventing damage and also promoting repair of peripheral nerves in human diabetic neuropathy.

Serum sex-hormone-binding globulin is related to hepatic and peripheral insulin sensitivity but not to beta-cell function in men and women with Type 2 diabetes mellitus

This study examined the relationship of hepatic and peripheral insulin sensitivity and beta-cell secretory function with serum sex hormone-binding globulin (SHBG) in men and women with Type 2 diabetes mellitus (DM). Fasting insulin, glucose and SHBG were measured in 58 Type 2 diabetic patients of both sexes (36 men) who were on diet treatment only and terms for insulin sensitivity and beta-cell secretion obtained by modelling. There was no significant difference in SHBG between men and women despite similar degree of obesity. SHBG was positively correlated (r = 0.41, p < 0.01) to hepatic insulin sensitivity derived from mathematical modelling of fasting glucose and insulin data using the homeostasis assessment model (HOMA). This relationship was independent of gender (men, r = 0.48, p < 0.01; women, r = 0.45, p < 0.05). Fasting insulin correlated negatively with SHBG in men (r = -0.34, p < 0.05). There were also significant negative correlations between SHBG and either plasma glucose (r = -0.29, p < 0.05) or body mass index (r = -0.34, p < 0.05). SHBG did not correlate with HOMA-modelled beta-cell function. In a multiple regression analysis, SHBG was independently correlated only with insulin sensitivity (p < 0.05). Further studies in 15 of the diabetic patients (11 men), showed a significant positive correlation (r = 0.52, p < 0.05) between SHBG and peripheral insulin sensitivity derived by continuous infusion of glucose with model assessment (CIGMA) but not between SHBG and CIGMA-modelled beta-cell function. These results indicate that both hepatic and peripheral insulin sensitivity are similarly related to serum SHBG in Type 2 diabetes of both sexes. The sex-difference in SHBG was abolished in the patients.

Guidelines for the diagnosis and outpatient management of diabetic peripheral neuropathy

Guidelines on the out-patient management of diabetic peripheral neuropathy have been developed from an international consensus meeting attended by diabetologists, neurologists, primary care physicians, podiatrists and diabetes specialist nurses. A copy of the full document follows this summary (Appendix 1). The document arose out of suggestions from Neurodiab, a subgroup of the European Association for the Study of Diabetes, that there was a need for guidelines developed by consensus, for the outpatient management of patients with diabetic neuropathy. An international consensus group was created, chaired by two of the authors. A pilot working party met in 1995, followed by a full working party of 39 experts, neurologists and diabetes physicians (Appendix 2). This compiled a draft guideline document which was circulated to a number of international bodies. After consultation with its members, the final guidelines were approved by Neurodiab (chairman F.A. Gries) towards the end of 1997.

Observations on severe ulnar neuropathy in diabetes

We describe the clinical and neurophysiologic findings in a group of diabetic patients with a severe ulnar neuropathy. All patients attending a large inner-city diabetes center were prospectively screening for hand wasting and weakness due to ulnar nerve disease. Twenty diabetic patients fulfilling the clinical criteria underwent nerve conduction studies and electromyography. All but one patient with a motor ulnar neuropathy had systemic complications, mostly severe: ten were amputees, four had had a renal transplant, and two were blind. The onset of hand weakness was sudden in five. All patients had a classical "ulnar hand" (bilateral in five) but forearm muscles were little affected. Sensory loss was prominent in only one-half. Nerve conduction studies showed markedly reduced ulnar motor responses (mean, 1.2 mV versus 7.4 mV in controls) and ulnar/median motor ratios. Motor conduction was disproportionately slowed across the elbows, with or without conduction block, in only eight of 34 affected ulnar nerves. Five of these patients had a habit of leaning on their elbows and/or a Tinel's sign. Median sensory action potentials (SAPs) were recordable in 12 patients but ulnar SAPs were absent in 30 of 34 affected nerves. Electromyography revealed advanced denervation of ulnar supplied hand muscles. We conclude that motor ulnar neuropathy is not uncommon in patients with diabetes of long standing, especially in those with severe systemic complications. Nerve entrapment at the elbows occurs in some, but in many the lesion is axonal, and damage may occur through ischemia.

The potential role of cell adhesion molecules in the pathogenesis of diabetic neuropathy

Cross-sectional studies have shown plasma cell adhesion molecules (CAMs) to be increased in patients with diabetes-related complications. In the first prospective study of CAMs, we have shown that plasma CAMs may be a predictor of the development of diabetic neuropathy. We followed up 28 diabetic patients (13 neuropathic) over a 5 year period, starting from 1991. All patients had peroneal nerve conduction velocity (PNCV), vibration perception threshold and plasma CAMs measured at baseline and follow-up. We found P-selectin and intercellular adhesion molecule-1 (ICAM-1) to be increased at baseline in patients with neuropathy compared to non-neuropathic patients. P-selectin and E-selectin were also found to be significantly higher at baseline in patients who at follow-up showed deterioration in PNCV of more than 3 m/s (p<0.05; p=0.01; respectively). P-selectin and ICAM-1 strongly correlated with PNCV. Univariate and multivariate regression analyses showed a significant inverse association between increasing log P-selectin, log E-selectin and log ICAM-1 with decreasing PNCV, and remained significant even after adjustment for glycaemic control. P-selectin and E-selectin, odds ratios of 8.8 (95% CI: 1.1-68.8; p=0.038) and 12.5 (95% CI: 1.2-132.1; p=0.036), respectively, were significantly associated with the risk of deterioration of PNCV after 5 years. This study suggests that plasma cell adhesion molecules may play an important role in the development and progression of peripheral neuropathy in diabetes mellitus.

Relationship of elevated urinary albumin excretion to components of the metabolic syndrome in non-insulin-dependent diabetes mellitus

Microalbuminuria is associated with increased morbidity and early mortality in non-insulin-dependent diabetes mellitus (NIDDM), mostly due to cardiovascular disease. This association may be due to a higher prevalence of known cardiovascular risk factors in those with microalbuminuria. We examined the relationship of microalbuminuria to components of the metabolic syndrome in 98 NIDDM patients with elevated urinary albumin excretion rate (UAER) (> 10.5 micrograms/min) (high UAER) and 102 normoalbuminuric NIDDM patients. Patients with high UAER were older than normoalbuminuric patients (P < 0.05), but they did not differ with respect to duration of diabetes, total cholesterol, body mass index (BMI) or the prevalence of smoking. A total of 58 (60%) patients with elevated UAER had two or more of hypertension, ischaemic heart disease (IHD), hypertriglyceridaemia and obesity compared with 41 (40%) in the normoalbuminuric group, (P < 0.05). Only nine (9.2%) high UAER patients had none of the above risk factors compared with 26 (25.5%) in the normoalbuminuric group (P < 0.01). The prevalence of hypertension (blood pressure (BP) > 160/95) was significantly higher in high UAER patients; 61/98 (62%) versus 39/102 (38%) in normoalbuminuric group, (P < 0.05). Elevated UAER was also associated with a higher risk of macrovascular disease (P < 0.01). The high UAER group included 50 Caucasian, 30 Asian and 18 Afro-Caribbean. The three groups did not differ with respect to total cholesterol, glycosylated haemoglobin (HbA1c) or prevalence of smoking. Asians had a lower BMI, a lower BP and a lower prevalence of peripheral vascular disease (PVD), but had a higher serum triglyceride (P < 0.01 for all) compared with Caucasian. Patients of Afro-Caribbean origin had a lower prevalence of IHD (0%) compared with both Asians (16%) and Caucasians (22%). Elevated UAER in NIDDM is closely associated with components of the metabolic syndrome and an increased risk of IHD and PVD. There are however, significant ethnic differences in this association.

Acupuncture for the treatment of chronic painful peripheral diabetic neuropathy: a long-term study

Forty-six diabetic patients with chronic painful peripheral neuropathy were treated with acupuncture analgesia to determine its efficacy and long-term effectiveness. Twenty-nine (63%) patients were already on standard medical treatment for painful neuropathy. Patients initially received up to six courses of classical acupuncture analgesia over a period of 10 weeks, using traditional Chinese Medicine acupuncture points. Forty-four patients completed the study with 34 (77%) showing significant improvement in their primary and/or secondary symptoms (P < 0.01). These patients were followed up for a period of 18-52 weeks with 67% were able to stop or reduce their medications significantly. During the follow-up period only eight (24%) patients required further acupuncture treatment. Although 34 (77%) patients noted significant improvement in their symptoms, only seven (21%) noted that their symptoms cleared completely. All the patients but one finished the full course of acupuncture treatment without reported or observed side effects. There were no significant changes either in the peripheral neurological examination scores, VPT or in HbA1c during the course of treatment. These data suggest that acupuncture is a safe and effective therapy for the long-term management of painful diabetic neuropathy, although its mechanism of action remains speculative.

Does peripheral neuropathy invariably accompany nephropathy in type 1 diabetes mellitus?

In patients with Type 1 diabetes mellitus complicated by diabetic nephropathy and retinopathy, it is usually believed that significant neuropathy is almost universal, but few studies have directly addressed this. This study assessed neuropathy in 91 such subjects, using vibration perception thresholds (VPT) and the neuropathy disability score (NDS). A total of 34% of subjects had no neuropathy on age adjusted VPT (z score) and 26% had no neuropathy on NDS. The severity of neuropathy as measured by VPT z score was related to increasing glycated haemoglobin (P = 0.02) and male sex (P = 0.03), and NDS was independently associated with age (P < 0.0001) and HbA1c (P = 0.003). These factors together accounted for only 12 and 31% of the total variance in VPT z score and NDS, respectively. In conclusion, the study has shown that a significant proportion of patients with diabetic nephropathy are free of neuropathy, but the full explanation for their protection from neuropathy is unclear.

Lowering the risk of neuropathy, foot ulcers and amputations

Peripheral neuropathy is one of the most common long-term complications of Type 2 diabetes. A population-based study in the north of England showed that 42% of Type 2 diabetic patients had clinical evidence of neuropathy. The Diabetes Control and Complications Trial (DCCT) has shown that the incidence of neuropathy in Type 1 diabetes can be reduced by over 50% with intensive therapy and optimal glycaemic control. Hyperglycaemia is believed to be a major aetiological factor in the development of neuropathy in Type 2 diabetes. Neuropathy cannot be diagnosed through history alone; therefore, careful examination of the feet for evidence of sensory loss and an assessment of the circulation must form part of the annual review of each patient. Peripheral somatic and autonomic neuropathy, together with peripheral vascular disease, are major contributing factors to the development of foot ulcers. In addition, abnormalities of foot shape (e.g. claw toes, prominent metatarsal heads) and the presence of plantar callus are signs of foot-ulcer risk. Effective patient education can reduce the incidence of foot ulceration and amputation by over 50%; therefore, all patients with a high risk of foot ulcers should be informed and, if indicated, referred for regular podiatry. The team approach to diabetic foot problems is an effective method of providing treatment for active ulcers. This should be followed by appropriate education, the provision of follow up and if indicated, suitable footwear and hosiery. Key members of the team are the podiatrist, the specialist nurse and the orthotist; medical staff may include the diabetologist and a vascular or orthopaedic surgeon. Thus, the risk of foot ulceration and amputation can be reduced by careful screening and patient education, without the need for expensive equipment.

Gait abnormalities in diabetic neuropathy

OBJECTIVE

To investigate the effect of peripheral neuropathy on gait in diabetic patients.

RESEARCH DESIGN AND METHODS

Gait analysis was performed in the following groups matched for age, sex, and BMI: 20 normal healthy control subjects (NC), 20 non-neuropathic diabetic control subjects (DC), 20 neuropathic diabetic subjects (DN), and 20 neuropathic diabetic subjects with a history of foot ulceration (DNU). All subjects with orthopedic foot problems were excluded from the study. The following gait parameters were investigated: 1) walking speed; 2) stance phase duration; 3) joint angles and moment arms for the ankle, knee, and hip joints in both sagittal and frontal planes; 4) the components of the ground reaction force (GRF) vector; and 5) the ankle, knee, and hip joint moments originating from the GRF vector in both planes.

RESULTS

There were no statistical differences in any of the parameters studied between the NC and DC groups. Walking speed was significantly slower in the DNU group compared with the two control groups (P < 0.02). The maximum knee joint angle was smaller in the sagittal plane for the DNU group compared with the DC group values (P < 0.05). The maximum value of the vertical component of GRF was found to be higher (P < 0.03) in the two control groups compared with the DNU group. The maximum value of the anteroposterior forces was also found to be higher (P < 0.001) in the DC group compared with the DNU group. The maximum frontal plane ankle joint moment was significantly higher (P < 0.05) in the DN compared with the NC group.

CONCLUSIONS

Diabetic subjects with peripheral neuropathy demonstrate alterations in some gait parameters during walking. These alterations could facilitate foot injuries, thus contributing to frequent foot ulceration.

Poor vision as a contributory factor in diabetic neuro-arthropathy

Two patients with longstanding insulin-dependent diabetes mellitus (IDDM) complicated by neuropathy, nephropathy and retinopathy leading to poor vision each developed a swollen and relatively painless foot. The previous day, both had been walking over uneven ground. At initial presentation, no X-ray was taken of the foot in case one and no action was taken over an undisplaced navicular fracture in case two. A few weeks later, a midfoot Charcot had developed in both cases. Poor vision may increase the risk of injury to the feet and may be an important risk factor for Charcot neuro-arthropathy. Plain radiographs are an important investigation for the swollen insensitive foot, even in the absence of pain.

Lack of association of angiotensin II type 1 receptor gene polymorphism with diabetic nephropathy in insulin-dependent diabetes mellitus

Several observations suggest that inherited factors are influential in the development of nephropathy in patients with insulin-dependent diabetes mellitus (IDDM). Genetic components of the renin angiotensin system are possible candidate genes. The aim of this study was to determine the role of the hypertension associated angiotensin II type 1 receptor (AT1R) gene A1166C polymorphism in susceptibility to nephropathy in IDDM. We examined 264 Caucasoid patients with IDDM and overt nephropathy (as defined by persistent proteinuria in the absence of other causes, hypertension and retinopathy), 136 IDDM patients with long duration of diabetes and no nephropathy (LDNN group), 200 recently diagnosed IDDM patients (Sporadic Diabetic group), and 212 non-diabetic subjects. The AT1R gene polymorphism was assessed using the polymerase chain reaction and restriction isotyping. Genotype frequencies did not differ significantly between the sporadic diabetic group and the nephropathy group (p = 0.245), nor between the long duration non-nephropathy group and the nephropathy group (p = 0.250). Allele frequencies were not significantly different between the three groups (p = 0.753). We conclude that there is no significant association between the hypertension associated AT1R gene polymorphism and diabetic nephropathy in patients with IDDM in the UK.

The pathogenesis of diabetic foot problems: an overview

Foot ulceration and lower limb amputation are still common complications of diabetes. Diabetic peripheral neuropathy and peripheral vascular disease are the most important etiologic factors, but there is a complex interplay between these abnormalities and a number of other contributory factors, such as altered foot pressures, limited joint mobility, glycemic control, ethnic background, and cardiovascular parameters. Identification of patients at high risk of ulceration is nevertheless simple, and education of such patients can achieve a major reduction in amputation and ulceration rates.

The tactile circumferential discriminator. A new, simple screening device to identify diabetic patients at risk of foot ulceration

OBJECTIVE

To evaluate the tactile circumferential discriminator (TCD) (Tacticon Medical Enterprises, West Chester, PA), a new, simple, handheld quantitative sensory testing device, in the identification of patients at potential risk of neuropathic ulceration.

RESEARCH DESIGN AND METHODS

Patients with diabetes (n = 133) attending the Manchester Diabetes Centre or diabetic foot clinic seen within a 5-week period were assessed using the TCD, monofilaments, and vibration perception threshold (VPT) measured over the hallux. The sensitivity and specificity of each method in the identification of "high-risk" patients were compared.

RESULTS

The TCD was easy to use, and there was a highly significant correlation between the results obtained compared with both filaments and VPT (P < 0.0001). Similarly, in the identification of patients at risk of ulceration, the TCD agreed with VPT in 75.2% of cases and with the monofilaments in 78.9%. In the identification of the 37 foot ulcer patients, TCD was highly sensitive (100%) but less specific (58.3%) than VPT (86.5%; 79.2%) and the monofilaments (91.9%; 76.0%).

CONCLUSIONS

These data suggest that the TCD is a simple and reliable new technique for population screening for neuropathy and foot ulcer risk.

Postural instability in diabetic neuropathic patients at risk of foot ulceration

Diabetic peripheral neuropathy is believed to cause postural instability due to abnormal proprioception. We assessed body sway in four groups, each of 20 subjects, matched for age, sex, and BMI: non-diabetic controls, non-neuropathic diabetic controls, subjects with diabetic neuropathy and no history of foot ulceration, and subjects with diabetic neuropathy and a history of foot ulceration. Postural sway was assessed on a Kistler force plate using the Romberg test, measuring the standard deviation of the centre of pressure in both sagittal (antero-posterior movement) and frontal (side to side movement) planes with eyes open and closed. The Romberg test results were log transformed and then analysed using analysis of variance followed by Newman-Keuls test. There was no significant difference in body sway between the two control groups and the first group of subjects with diabetic neuropathy. However, in patients with a history of ulceration, values were significantly higher (p < 0.05) compared to all other groups in both planes and conditions studied. These results are suggestive of a relationship between impaired body sway control and foot ulceration. Postural instability may have clinical significance and increase the risk of minor trauma and ulceration in patients with diabetic neuropathy.

The relationship of static foot structure to dynamic foot function

Many theories have been advanced concerning the relationship between structure and function in the human foot, yet few of these theories have been subjected to quantitative examination. In this study, foot structure was characterized by 27 measurements taken from standardized lateral and dorsi-plantar weight-bearing plain radiographs of 50 healthy adult subjects. Regional plantar pressure distribution data collected from the same feet were chosen as the functional measures. A stepwise regression analysis was performed to (1) explore what portion of the variance in peak plantar pressure during walking can be explained by the radiographic measurements, and (2) identify structural characteristics of the foot which are significant predictors of peak plantar pressure under the heel and the first metatarsal head (MTH1). Most of the radiographic measurements were highly reliable. However, only 31 and 38% of the variance in peak plantar pressure at the heel and MTH1, respectively, could be explained using multiple regression analyses with the radiographic measurements as independent variables. Among the structural predictors that were identified, soft tissue thickness (e.g. calcaneus or sesamoid heights), and arch-related measurements were the strongest predictors of plantar pressure under both the heel and the first metatarsal head. We conclude that, in normal subjects, only about 35% of the variance in dynamic plantar pressure can be explained by the measurements of foot structure derived from radiographs. This implies that the dynamics of gait are likely to exert the major influences on plantar pressure during walking.

A randomised controlled trial of topical glycopyrrolate, the first specific treatment for diabetic gustatory sweating

The treatment of gustatory sweating in diabetes mellitus is usually with oral anti-cholinergic drugs, but these frequently lead to unacceptable side effects. Glycopyrrolate is an anti-muscarinic agent that can be applied topically and is efficacious in gustatory sweating occurring in other conditions. In a double-blind placebo-controlled crossover study, we assessed the value of glycopyrrolate in 13 diabetic patients with gustatory sweating. Sweating was measured by a sweat challenge, and diaries recorded by the patients throughout the 2 weeks of each treatment period. Compared to placebo, glycopyrrolate reduced the sweat response to a challenge by 82% (p < 0.01). The frequency of episodes of gustatory sweating during the treatment period was also reduced by 51% (p < 0.01), with a nearly 100% reduction in the frequency of episodes of severe sweating (p < 0.01). In conclusion, topically applied glycopyrrolate is a very effective treatment in reducing both the severity and frequency of diabetic gustatory sweating.

Do people with diabetes wear their prescribed footwear?

Ill-fitting shoes are a common cause of foot ulceration in people with diabetes mellitus and prescribed footwear is used to prevent and treat such lesions. However, footwear is only effective if worn and the shoes supplied have to be acceptable to the patient. A study of patients who were supplied with footwear at a diabetic foot clinic was conducted using face-to-face interviews and a structured questionnaire, to assess footwear usage and patient preference. Of the 50 subjects who participated, only 11 (22%) regularly wore their prescribed footwear and 19 (38%) subjects wore slippers indoors. Only 12 subjects (24%) were aware of the cost of their shoes. Most subjects were happy with their footwear and the service which was provided, whereas 9 (18%) disliked the style of their shoes and stated that they were not cosmetically acceptable. Thus, although expensive footwear is supplied to patients to prevent and treat foot ulcers, it may not be used as intended. If shoes are to be worn, a wider choice of footwear should be available to the wearer.

Gustatory sweating in diabetes mellitus

Gustatory sweating has been only rarely reported in diabetes mellitus and is thought to be due to axonal regeneration within the autonomic nervous system. We investigated the relationship of gustatory sweating to other diabetic complications. 196 patients in four groups (diabetic nephropathy, diabetic neuropathy, diabetic controls, and non-diabetic renal failure) were questioned about gustatory sweating. Somatic and autonomic neuropathy were assessed by clinical signs, vibration perception threshold, and heart rate variability. Sixty-nine percent of patients with nephropathy and 36% of those with neuropathy reported gustatory sweating, whereas less than 5% reported it in the other two groups. Five subjects reported that gustatory sweating either disappeared or significantly improved immediately after renal transplantation. Analysis of the nephropathy and neuropathy groups separately showed a strong correlation between gustatory sweating and degree of neuropathy (p < 0.01). This study shows that gustatory sweating is much more common than previously believed and demonstrates that it is often very closely linked with diabetic nephropathy.