Prevalence of diabetic peripheral neuropathy and its relation to glycaemic control and potential risk factors: the EURODIAB IDDM Complications Study

Understanding the impact of painful diabetic neuropathy

Painful neuropathy is a common and often distressing complication of diabetes. It has considerable impact on the social and psychological well-being of affected individuals. There are two distinct forms of painful neuropathy: an acute and self-limiting form that resolves within a year or a chronic form that can go on for years. There are now a number of drugs available for the treatment of neuropathic pain. However, some may fail to respond to these drugs or may have unacceptable adverse side effects. When this is the case, the patient's quality of life can be severely affected. Health care professionals need to assess the full impact of painful neuropathy. In this article we review a number of instruments that are used to assess the severity of painful neuropathy and its impact on the quality of life.

Validation of the Toronto Clinical Scoring System for diabetic polyneuropathy

OBJECTIVE

The aim of the current study was to determine the validity of the Toronto Clinical Scoring System (CSS) in reflecting the presence and severity of diabetic peripheral sensorimotor polyneuropathy (DSP) as determined by myelinated fiber density (FD) on sural nerve biopsy.

RESEARCH DESIGN AND METHODS

Eighty-nine patients with both type 1 and type 2 diabetes, ascertained from a large therapeutic randomized controlled trial, were included in this cross-sectional, observational cohort study. Morphological severity of DSP was expressed as the FD in the sural nerve biopsy. The Toronto CSS was applied to all patients to determine a clinical neuropathy score. General linear regression models were used to assess the relationship between the morphological severity of DSP and the Toronto CSS.

RESULTS

The Toronto CSS showed a significant negative correlation with sural nerve FD (R(2) = 0.256, P < 0.0001). The Toronto CSS was lower in those with better glycemic control (HbA(1c) </=8%). Sural nerve FD and the Toronto CSS showed strong correlations with electrophysiology, by both summed amplitude and summed conduction velocity values.

CONCLUSIONS

The Toronto CSS is a valid instrument to reflect the presence and severity of DSP as measured by sural nerve morphology and electrophysiology. The results of the current study underscore the interrelationships between clinical deficits, electrophysiological findings, and morphological changes in DSP. This evidence suggests that the Toronto CSS may prove useful in documenting and monitoring DSP in the clinic and in clinical research trials.

Autonomic neuropathy is associated with increased cardiovascular risk factors: the EURODIAB IDDM Complications Study

AIMS

To assess the prevalence of and risk factors for autonomic neuropathy in the EURODIAB IDDM Complications Study.

METHODS

The study involved the examination of randomly selected Type I (insulin-dependent) diabetic patients from 31 centres in 16 European countries. Neuropathic symptoms and two tests of autonomic function (changes in heart rate and blood pressure from lying to standing) were assessed and data from 3007 patients were available for the present analysis. Autonomic neuropathy was defined as an abnormality of at least one of the tests.

RESULTS

The prevalence of autonomic neuropathy was 36% with no sex differences. The frequency of one and two abnormal reflex tests was 30% and 6%, respectively. The R-R ratio was abnormal in 24% of patients while 18% had orthostatic hypotension defined as a fall in systolic blood pressure > 20 mmHg on standing. Significant correlations were observed between autonomic neuropathy and age (P < 0.01), duration of diabetes (P < 0.0001), HbA1c (P < 0.0001), diastolic blood pressure (P < 0.05), lower HDL-cholesterol (P < 0.01), the presence of retinopathy (P < 0.0001) and albuminuria (P < 0.0001). New associations have been identified from the study: the strong relationship of autonomic neuropathy to cigarette smoking (P < 0.01), total cholesterol/HDL-cholesterol ratio (P < 0.05) and fasting triglyceride (P < 0.0001). As a key finding, autonomic neuropathy was related to the presence of cardiovascular disease (P < 0.0001). All analyses were adjusted for age, duration of diabetes and HbA1c. However, data have been only partly confirmed by logistic regression analyses. Frequency of dizziness on standing up was 18%, while only 4% of patients had nocturnal diarrhoea and 5% had problems with bladder control.

CONCLUSION

Cardiovascular reflex tests, even in the form of the two tests applied, rather than a questionnaire, seem to be appropriate for the diagnosis of autonomic neuropathy. The study has identified previously known and new potential risk factors for the development of autonomic neuropathy, which may be important for the development of risk reduction strategies. Our results may support the role of vascular factors in the pathogenesis of autonomic neuropathy.

Treatment of chronic painful diabetic neuropathy with isosorbide dinitrate spray: a double-blind placebo-controlled cross-over study

OBJECTIVE

Considerable evidence implicates impaired nitric oxide (NO) generation in the pathogenesis of diabetic neuropathic pain. We therefore conducted a pilot study to examine the effects of isosorbide dinitrate (ISDN), a NO donor with local vasodilating properties, in spray form in the management of chronic neuropathic pain.

RESEARCH DESIGN AND METHODS

The study was of double-blind, randomized, placebo-controlled, and two-period cross-over design. After a 2-week run-in period, 22 diabetic patients (13 men, 20 with type 2 diabetes, age [mean +/- SE] 63.7 +/- 1.8 years, duration of diabetes 9.1 +/- 1.5 years, duration of painful neuropathy 2.6 +/- 0.4 years) were randomized to receive ISDN or placebo sprays for 4 weeks, exchanging their treatment for a further 4 weeks after a 2-week wash-out period. The patients administered the spray to both feet before bedtime. Biweekly pain and other sensory symptoms were assessed using a visual analog scale (VAS) and the Lickert scale, respectively.

RESULTS

ISDN spray reduced overall neuropathic pain (P = 0.02) and burning sensation (P = 0.006). No treatment difference was observed with other sensory modalities (hot/cold sensation, tingling, numbness, hyperesthesia, and jabbing-like sensation). At study completion, 11 patients (50%) reported benefit and wished to continue using the ISDN spray, 4 (18%) preferred the placebo spray, and the remaining 7 (32%) were undecided.

CONCLUSIONS

ISDN spray offers an alternative and effective pharmacological option in relieving overall pain and burning sensation in the management of painful diabetic neuropathy. The potential of ISDN spray in alleviating other specific sensory symptoms associated with diabetic peripheral neuropathy merits further study.

Neuronal Ca2+ disregulation in diabetes mellitus

The Ca(2+) hypothesis of brain ageing and dementia may account for part of the available data on the pathogenesis of dementia and certain neurodegenerative disorders. The hypothesis proposes that disturbances in the homeostasis of neuronal cytosolic free Ca(2+) are part of a final common pathway, ultimately leading to neuronal dysfunction and cell death. The hypothesis also proposes that a small change in cytosolic free Ca(2+) sustained over a long period of time will result in similar damage as a large change over a short period. Diabetes mellitus is associated with neurological complications in the peripheral and central nervous system, as reflected in peripheral neuropathy, modest cognitive impairments and an increased risk of dementia. In animal models of diabetes, learning impairments are associated with alterations in Ca(2+) -dependent forms of hippocampal synaptic plasticity. Disturbances in the homeostasis of cytosolic free Ca(2+) may present a final common pathway in the multifactorial pathogenesis of neurological complications of diabetes, which involves vascular changes, oxidative stress, and non-enzymatic protein glycation. In line with the Ca(2+) hypothesis of neurodegenerative disorders, a prolonged, small increase in basal cytosolic Ca(2+) levels indeed exists in sensory neurones of diabetic animals. In addition, Ca(2+) dynamics are affected. Ca(2+) channel blockers, such as nimodipine, have been shown to improve experimental peripheral neuropathy, through a vascular mechanism, possibly in combination with direct neuronal effects. Preliminary studies indicate that nimodipine may also improve Ca(2+)-dependent forms of synaptic plasticity in the hippocampus of diabetic rats.

Haemodynamics in microvascular complications in type 1 diabetes

Type 1 diabetes is commonly associated with microvascular complications. Most of the microvascular blood vessels are involved but those in the kidney, retina and large nerves exhibit the more significant pathology. Haemodynamic and metabolic factors both alone and through the activation of a common pathway contribute to the characteristic dysfunction observed in diabetic vasculopathy. The haemodynamic abnormalities in type 1 diabetes are characterized by increased systemic blood pressure and altered blood flow with subsequent activation of various vasoactive factors, which can contribute to the maintenance of the haemodynamic alterations and to the development and progression of the microvascular complications. These vasoactive factors include vasoconstrictors such as angiotensin II, and endothelin, as well as vasodilators such as nitric oxide (NO). Systemic hypertension and vasoactive factors independently and in interaction with the metabolic pathway activate intracellular second messengers, nuclear transcription factors and various growth factors which lead to the typical functional and structural alterations of diabetic microvascular complications. Therapeutic strategies involved in the management and prevention of diabetic complications currently include antihypertensive agents, particularly those that interrupt the renin-angiotensin system. Further understanding of the interactions among the vasoactive factors, the intracellular second messengers and the growth factors may help to identify novel strategies to influence the action of the vasoactive factors. These novel therapies, together with specific inhibitors of the metabolic pathway or the common pathway, may provide the possibility of preventing or even reversing the progression of diabetic microvascular complications.

Neurovascular disease, antioxidants and glycation in diabetes

People with diabetes are ten to fifteen times more likely to have a lower limb amputation (LLA) than non-diabetic individuals. Fifteen percent of people with diabetes will develop a foot ulcer during their lifetime, the rate of major amputation amongst diabetic individuals continues to rise, foot problems remain the commonest reason for diabetes-related hospitalisation and recurrence rates in patients with previous foot ulcers are 50% or more. Hyperglycaemia-induced oxidative stress has been shown to result in decreased nerve conduction velocity, and decreased endoneural blood flow-both precursors for neuropathy. Vitamin antioxidants have been shown to be effective therapy in experimental models in reducing free radical species and inhibiting the oxidative process in diabetes subjects. Little work has been published, however, regarding the dietary use of antioxidants from foods, and their specific effects on neurovascular disease and glycation within the diabetes population. Aetiological and prevention studies with dietary antioxidants from foods aimed at the complex nature of foot problems in diabetes are needed.

The forefoot-to-rearfoot plantar pressure ratio is increased in severe diabetic neuropathy and can predict foot ulceration

OBJECTIVE

We have previously demonstrated that high plantar pressures can predict foot ulceration in diabetic patients. The aim of the present study was to evaluate both the relationship between forefoot and rearfoot plantar pressure in diabetic patients with different degrees of peripheral neuropathy and their role in ulcer development.

RESEARCH DESIGN AND METHODS

Diabetic patients of a 30-month prospective study were classified according to the neuropathy disability score: scores of 0, 1-5, 6-16, and 17-28 are defined as absent (n = 20), mild (n = 66), moderate (n = 95), and severe (n = 57) neuropathy, respectively. The F-Scan mat system was used to measure dynamic plantar pressures. The peak pressures under the forefoot and the rearfoot were selectively measured for each foot, and the forefoot-to-rearfoot ratio (F/R ratio) was calculated.

RESULTS

Foot ulcers developed in 73 (19%) feet. The peak pressures were increased in the forefoot of the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (6.2 +/- 4.5 and 3.8 +/- 2.7 vs. 3.0 +/- 2.1 and 3.3 +/- 2.1 kg/cm(2) [mean +/- SD], respectively; P < 0.0001). The rearfoot pressures were also higher in the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (3.2 +/- 2.0 and 3.2 +/- 1.9 vs. 2.5 +/- 1.3 and 2.3 +/- 1.0, respectively; P < 0.0001). The F/R ratio was increased only in the severe group compared with the moderate and mild neuropathic and non-neuropathic groups (2.3 +/- 2.4 vs. 1.5 +/- 1.2, 1.3 +/- 0.9, and 1.6 +/- 1.0, respectively; P < 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11-1.28], P < 0.0001) and the F/R ratio (1.37 [1.16-1.61], P < 0.0001) were related to risk of foot ulceration, whereas rearfoot pressure was not.

CONCLUSIONS

Both the rearfoot and forefoot pressures are increased in the diabetic neuropathic foot, whereas the F/R ratio is increased only in severe diabetic neuropathy, indicating an imbalance in pressure distribution with increasing degrees of neuropathy. This may lend further evidence toward the concept that equinus develops in the latest stages of peripheral neuropathy and may play an important role in the etiology of diabetic foot ulceration.

No correlation between impairment of cerebrovascular reserve capacity and electrophysiologically assessed severity of neuropathy in noninsulin-dependent diabetes mellitus

INTRODUCTION

Microvascular abnormalities have an important role in the most frequent neurological complications of diabetes mellitus: neuropathy and cerebrovascular disorders. Severity of neuropathy as well as of cerebral microvascular damage can be quantitatively evaluated by instrumental methods like nerve conduction studies and transcranial Doppler. In the present study, we investigated whether a correlation exists between the severity of peripheral neuropathy and the impairment of cerebrovascular reserve capacity (CRC) in 20 patients with Type 2 diabetes mellitus.

METHODS

CRC was measured by transcranial Doppler and defined as the maximal percentage increase in blood flow velocity in the middle cerebral artery within 20 min after an intravenous dose of 1000 mg of acetazolamide. Nerve conduction studies of the median, ulnar, peroneal, and sural nerves were performed. Severity of neuropathy was scored based on conduction velocities, amplitudes, and distal latencies.

RESULTS

There was no correlation between the neuropathic score and CRC (R= .003, P= .99). Neither CRC nor the neuropathic score correlated significantly with age, duration of diabetes, and serum values of HbA(1c), glucose, insulin, von Willebrand factor, and alpha(2) - macroglobulin. Severity of neuropathy but not CRC correlated with microalbuminuria (R= .47, P= .038 and R= .14, P= .54). Improper treatment reflected by HbA(1c) >10% was associated with significantly more severe albuminuria, higher actual blood glucose level, higher von Willebrand factor activity, and marginally higher neuropathic score (21 vs. 13, P=.096), but was not associated with CRC (44% vs. 42%, P= .81). When duration of diabetes was dichotomized to 15 years and less or over 15 years, CRC was significantly smaller (35% vs. 50%, P= .036) and neuropathy was more severe in the subgroup with longer diabetes duration (19 vs. 11.5 points, P= .07).

CONCLUSIONS

Although both CRC and peripheral nerve function are affected more severely in patients with long-lasting Type 2 diabetes mellitus, damage in the cerebrovascular system and in the long peripheral nerves occur independently. As in diabetes mellitus pathological changes in autonomic and large peripheral nerves develop simultaneously, decreased CRC in diabetic patients might be predominantly due to structural changes of resistance arteries or to metabolic than to neurogenic factors.

Prevalence of Q-T interval dispersion in type 1 diabetes and its relation with cardiac ischemia : the EURODIAB IDDM Complications Study Group

OBJECTIVE

The interlead variation in duration of the Q-T interval on the surface electrocardiogram (Q-T interval dispersion [QTd]) has been shown to predict mortality in type 2 diabetic patients. We evaluated the prevalence of QTd prolongation in the EURODIAB population and its relation to corrected Q-T interval (QTc), sex, age, duration of diabetes, blood glucose control, and complications. RESEARCH DESIGN AND METHODS; A total of 3,042 type 1 diabetic patients were studied. QTc was calculated according to the Bazett's formula; QTc > 0.44 s was considered abnormally prolonged. QTd was calculated using the difference between the maximum and the minimum QTc in any thoracic lead. QTd >0.080 s was considered abnormally prolonged.

RESULTS

The prevalence of an increased QTd was 7%. A significant relation was observed between QTd prolongation and diastolic blood pressure (P < 0.05). A higher prevalence of QTd prolongation was observed in patients with ischemic heart disease (P = 0.004), whereas no relationship was observed with retinopathy, albumin excretion rate, or measures of somatic and autonomic neuropathy. QTc and QTd were significantly related (P = 0.001); however, a proportion of patients with normal QTd showed a prolonged QTc (>0.44 s).

CONCLUSIONS

In patients with type 1 diabetes, QTd is associated with ischemic heart disease and diastolic blood pressure but not neuropathy. Although QTd is statistically related to duration of QTc, increased QTd and increased QTc identify different patients, and their predictive value deserves prospective evaluation.

Lower limb nerve impairment in diabetic patients: multiperspective assessment

To assess the relationship between patient's perception of his own inferior limbs symptom and function and the clinical-neurophysiological assessment in patients affected by insulin-dependent diabetes mellitus (IDDM). We studied 50 consecutive outpatients affected by IDDM (23 men, 27 women). We used validated measurements clinical [Semmes-Weinstein (SW), vibration perception threshold (VPT), muscle strength, osteotendineous reflexes, etc.], neurophysiological (sural, peroneal nerves), metabolic and patient-oriented [North American Spine Society (NASS) questionnaire]. Patient-oriented scores were significantly related with neurophysiological findings of the inferior limbs. Our data suggest that electrodiagnostic tests are useful to assess the severity of the diabetic polyneuropathy not only because they provide a biological measurement of the nerve function but also because they appeared related to the patient's quality of life related to the peripheral nerve involvement.

Risk factors for diabetic neuropathy and foot ulceration

Peripheral sensory neuropathy (PSN) and foot ulcers are disabling and expensive complications of diabetes with few therapeutic options. Knowledge of risk factors for both complications, based on prospective observational studies, permits identification of individuals at high risk and provides options for intervention. Glycemia is the main modifiable risk factor for PSN, whereas PSN and trauma are the principal potentially modifiable risk factors for the development of foot ulceration.

Measurement of somatic neuropathy for clinical practice and clinical trials

Distal sensory polyneuropathy is a common and unpleasant complication of diabetes mellitus. It is the main initiating factor for foot ulceration. The increasing prevalence of diabetes has important associated health implications, both in terms of morbidity and mortality, and results in the consumption of scarce medical resources. Identification of somatic neuropathy in clinical practice is therefore important for targeted educational and other interventions. In this article, we describe methods for detecting somatic neuropathy in clinical practice and highlight those tests that are proven to be predictors of foot ulceration. The approach for detecting and characterizing somatic neuropathy for clinical trials, however, differs significantly. These methods must ideally have high levels of reproducibility, sensitivity, and specificity. Currently, several neurophysiologic tests are employed in clinical trials in order to accurately characterize diabetic neuropathy. The recent introduction of the computer-assisted programs for the measurement of sensory modalities for clinical trials has been a major advance. Due to their invasive nature and associated morbidity, nerve biopsy studies are no longer used in clinical trials. Recently, using magnetic resonance imaging (MRI), significant spinal cord atrophy has been demonstrated in established neuropathy. If this observation proves to be an early feature, then a relatively rapid, noninvasive MRI technique may be used in the future to characterize diabetic neuropathy.

Reduced Ia-afferent-mediated Hoffman reflex in streptozotocin-induced diabetic rats

In addition to reduced nerve conduction velocity, diabetic neuropathic patients often exhibit a reduction in the amplitude of the compound muscle action potential elicited by stimulation of the Ia-afferent-mediated reflex pathway (Hoffman or H wave) that can contribute to diminished or absent tendon reflexes. In contrast to nerve conduction velocity deficits, changes in H-wave amplitudes have not been reproduced in diabetic animal models. Using electrophysiological techniques developed for repeated recordings in individual animals, we report H-wave deficits in streptozotocin (STZ)-treated insulin-dependent diabetic rats. After 4 weeks of diabetes induced by STZ treatment, a 47% reduction in the H-wave amplitude was demonstrated by recording compound muscle action potentials in foot muscles after stimulation of Ia afferents. Interestingly, we also demonstrate that the H-wave amplitude gradually recovers to a 26% deficit after 12 weeks of experimental diabetes. The recovery of the H wave in STZ-treated rats distinguishes this deficit mechanistically from other STZ-induced electrophysiological changes and may model a similar recovery of the H wave reported in diabetic patients.

Tactile directional sensibility and diabetic neuropathy

Five different procedures used to diagnose neuropathy were compared in a "blind" study with diabetic patients. The aim was to evaluate tests of tactile directional sensibility. Three matched groups were examined, two groups with type I diabetes, either with or without suspected neuropathy, and one of healthy controls. Testing consisted of: (1) examination by a specialist in neurology, (2) electrophysiologic measurement of nerve conduction velocity and determination of cool sensitivity, and (3) determination of directional sensibility in two stages, with categorical and quantitative techniques. Abnormal test results were obtained for both groups of diabetic patients. Quantitatively measured directional sensibility had the highest sensitivity (89%) and specificity (85%) when calculated for patients who had received a diagnosis of neuropathy from the neurologist, despite one case of abnormal directional sensibility among the healthy controls. Conduction velocity testing was almost comparably sensitive (80%) and cool sensitivity, comparably specific (85%) when calculated in the same manner.

Factors associated with plasma lipids and lipoproteins in type 1 diabetes mellitus: the EURODIAB IDDM Complications Study

AIM

To assess the determinants and prevalence of hyperlipidaemia in Type 1 diabetic patients in the EURODIAB IDDM Complications Study.

METHODS

Standardized questionnaire data were obtained and anthropometric and biochemical measurements performed on 3159 Type 1 diabetic patients, randomly selected from 31 diabetes clinics. Plasma lipid levels were determined centrally, using enzymatic methods

RESULTS

Plasma total cholesterol, high-density lipoprotein cholesterol (HDL-C), and HDL subfractions were higher in women than in men, while plasma triglycerides were higher in men (P < 0.001). Total cholesterol, low-density lipoprotein cholesterol (LDL-C) and HDL-C and HDL-C subfractions were, as expected, significantly associated with age and HbA1c in both sexes. Age and HbA1c adjusted values of triglyceride, total cholesterol, LDL-C, HDL-C and HDL3-C in men and triglyceride and HDL2-C in women showed significant associations with central obesity, measured as the waist to hip ratio (WHR). Current smokers had lipid profiles characteristic of insulin resistance in comparison to nonsmokers. Significant positive associations were observed between hypertension and plasma triglycerides, total cholesterol and LDL-C in men and women. In men, degree of physical activity was negatively associated with triglyceride and positively related to HDL-C and HDL3-C. The prevalence of LDL-hypercholesterolaemia (LDL-C > 3.35 mmol/L) was 45% in men and in women, while plasma triglyceride levels > 1.7 mmol/L were observed in 12% of men and 8% of women.

CONCLUSION

The results of this study indicate that lipid levels in Type 1 diabetic patients are strongly influenced by smoking habit and central obesity in a way that is characteristic of the insulin resistance syndrome.

Blood pressure response to standing in the diagnosis of autonomic neuropathy: the EURODIAB IDDM Complications Study

Autonomic neuropathy is associated with poor prognosis. Cardiovascular reflexes are essential for the diagnosis of autonomic nerve dysfunction. Blood pressure response to standing is the most simple test for the evaluation of sympathetic integrity, however it is still discussed which diagnostic criteria of abnormal response should be considered as optimal. The EURODIAB IDDM Complications Study involved the examination of randomly selected Type 1 diabetic patients from 31 centres in 16 European counties. Data from 3007 patients were available for the present evaluation. Two tests of autonomic function (response of heart rate /R-R ratio/ and blood pressure from lying to standing) just as the frequency of feeling faint on standing up were assessed. R-R ratio was abnormal in 24% of patients. According to different diagnostic criteria of abnormal BP response to standing (>30 mmHg, >20 mmHg, and >10 mmHg fall in systolic BP), the frequency of abnormal results was 5.9%, 18% and 32%, respectively (p < 0.001). The frequency of feeling faint on standing was 18%, thus, it was identical with the prevalence of abnormal blood pressure response to standing when >20 mmHg fall in systolic blood pressure was considered as abnormal. Feeling faint on standing correlated significantly with both autonomic test results (p < 0.001). A fall >20 mmHg in systolic blood pressure after standing up seems to be the most reliable criterion for the assessment of orthostatic hypotension in the diagnosis of autonomic neuropathy in patients with Type 1 diabetes mellitus.

Drug treatment effects on disease progression

Degenerative diseases are characterized by a worsening of disease status over time. The rate of deterioration is determined by the natural rate of progression of the disease and by the effect of drug treatments. A goal of drug treatment is to slow disease progression. Drug treatments can be categorized as symptomatic or protective. Symptomatic treatments do not affect the rate of disease progression whereas protective treatments have the ability to slow disease progression down. Many current methods for describing disease progression have two common drawbacks: a linear relationship between time and disease status is assumed, and within- and between-subject variability is ignored. Disease progress models combined with pharmacokinetic pharmacodynamic models and hierarchical random effects statistical models provide insights into understanding the time course and management of degenerative disease.

New trends in the etiopathogenesis of diabetic peripheral neuropathy

Neuropathy is well recognized as a major complication of insulin-dependent diabetes mellitus in adults, resulting in significant morbidity and possibly an increased mortality. Both the peripheral and autonomic nervous systems can be involved, and adolescents with diabetes can show early evidence of neuropathy. The pathogenesis of diabetic neuropathy remains unclear but is thought to involve various mechanisms. This complication can be traced to the metabolic effects of hyperglycemia and/or other effects of insulin deficiency on the various constituents of the peripheral nerve. The polyol pathway and/or nonenzymatic glycation affecting one or more cell types in the multicellular constituents of the peripheral nerve appear likely to have an inciting role. The role of other factors, such as possible direct neurotrophic effects of insulin and insulin-related growth factors, seems to be relevant.

Men's reproductive and sexual health

A broad definition of men's reproductive and sexual health (MRSH) includes medical (pathophysiological) matters such as sexually transmitted infections (STIs), developmental anomalies, malignancy, trauma, and infertility. It also includes psychosocial concerns: sexuality, contraception, disease prophylaxis, developmental and lifecycle issues, tobacco and drug use, sexual identity and orientation, and partnership issues. College men, of whom a large majority are sexually active, have a range of MRSH needs, including some that are particular to their age and social environment. To reach men effectively requires approaches that are somewhat different from those used with women. Clinicians in college health services are in an excellent position to help young men recognize the importance of reproductive health and sexual responsibility. College health services therefore should offer men screening; clinical diagnosis and treatment for MRSH conditions; and information, education, and counseling services, in a manner designed to meet their unique needs.

Glycemic control is related to the morphological severity of diabetic sensorimotor polyneuropathy

OBJECTIVE

The aim of the current study was to determine the independent clinical risk factors for predicting morphological severity of distal diabetic sensorimotor polynecuropathy (DSP) as determined by fiber density (FD) on sural nerve biopsy.

RESEARCH DESIGN AND METHODS

A total of 89 patients with both type 1 and type 2 diabetes, ascertained from a large therapeutic randomized clinical trial, were included in this observational cohort study. Morphological severity of DSP was expressed as the myelinated FD in the sural nerve biopsy General linear models were used to assess the relationship between the morphological severity of DSP and various clinical risk factors.

RESULTS

Glycated hemoglobin (GHb) was significantly related to FD in univariate and multivariate regression analyses. This relationship was present in models in which GHb was handled either as a continuous variable or as a categorical variable with the highest significance level, with a GHb cutoff level of 9%. After dividing patients into groups with optimal to moderate GHb < or = 9%) and suboptimal (GHb >9%) glycemic control, the difference in FD between the two groups ranged between 3,461 and 2,334 per mm2. FD was also significantly related to duration of diabetes and age of the patient.

CONCLUSIONS

The severity of peripheral DSP expressed by morphological criteria was significantly related to glycemic control in type 1 and type 2 diabetic patients. Inconsistent with previously published electrophysiological data demonstrating a correlation between height and conduction velocity, increasing height is not associated with morphological severity. Based on the results of the present study, it might be hypothesized that improving glycemic control will lessen severity of DSP in terms of FD loss in subjects with diabetes.

Glycemic index in the diet of European outpatients with type 1 diabetes: relations to glycated hemoglobin and serum lipids

BACKGROUND

Little is known about the variation of the glycemic index (GI) in the diet of European outpatients with type 1 diabetes and how the GI of a commonly consumed diet is associated with metabolic control.

OBJECTIVE

The present study examined the calculated dietary GI of European outpatients with type 1 diabetes for possible relations to glycated hemoglobin (Hb A(1c)) and serum lipid concentrations.

DESIGN

The relation of the GI (calculated from a 3-d dietary record) to Hb A(1c), serum cholesterol (total, LDL, and HDL), and fasting triacylglycerol was analyzed in 2810 people with type 1 diabetes from the EURODIAB Complications Study.

RESULTS

The GI was independently related to Hb A(1c) (P = 0.0001). Compared with the highest GI quartile (median GI: 89), adjusted Hb A(1c) in the lowest GI quartile (median GI: 75) was 11% lower in patients from southern European centers and 6% lower in patients from northern, western, and eastern European centers. Of the serum lipids, only the HDL cholesterol in patients from these European centers was independently related to the GI (P = 0.002). In southern European centers, the consumption of pasta, temperate-climate fruit, white bread, and potatoes largely determined the patients' dietary GI, whereas in the northern, western, and eastern European centers, consumption of bread, potatoes, and temperate-climate fruit was most relevant.

CONCLUSIONS

This study in European patients with type 1 diabetes showed that a lower dietary GI is related to lower Hb A(1c) concentrations, independently of fiber intake. The consumption of bread and pasta had the biggest effect on the overall dietary GI of European outpatients.

Peripheral neuropathy does not invariably coexist with autonomic neuropathy in diabetes mellitus

Background: Peripheral somatic and autonomic neuropathies are the most common types of diabetic polyneuropathy. Although duration and degree of hyperglycemia are considered to be risk factors for both autonomic and peripheral neuropathy, recent studies have raised the question of a different development and natural history of these neuropathies in diabetes. In addition, a few studies have investigated the relationship between chronic painful and autonomic neuropathy. The aim of this study was to investigate to what extent autonomic and peripheral neuropathy coexist, as well as whether painful neuropathy is more common in diabetic patients with autonomic neuropathy. Methods: Subjects with type 1 (n=52; mean age 31.7 years) and type 2 diabetes (n=53; mean age 54.5 years) were studied. Evaluation of peripheral neuropathy was based on clinical symptoms (neuropathic symptom score), signs (neuropathy disability score), and quantitative sensory testing (vibration perception threshold). Assessment of autonomic neuropathy was based on the battery of standardized cardiovascular autonomic function tests. Results: Prevalence rates of pure autonomic and of pure peripheral neuropathy in patients with type 1diabetes were 28.8 and 13.5%, respectively. The respective rates in patients with type 2 diabetes were 20.7% (P=0.33 vs. type 1 diabetes) and 20.7% (P=0.32). Peripheral and autonomic neuropathy coexisted in 28.8% of type 1 and in 45.3% of type 2 diabetic subjects (P=0.08). Prevalence rates of chronic painful neuropathy in subjects with type 1 diabetes, with and without autonomic neuropathy, were 16.6 and 22.7%, respectively (P=0.85) and in type 2 diabetic subjects 20 and 22.2%, respectively (P=0.58). Multivariate analysis after adjustment for age, sex, blood pressure, duration of diabetes, HBA(1c), and presence of retinopathy or microalbuminuria showed that neither the indices of peripheral nerve function (neuropathic symptom score, neuropathy disability score, vibration perception threshold) nor the presence of peripheral neuropathy or chronic painful neuropathy are associated with the presence of autonomic neuropathy in individuals with either type 1 or type 2 diabetes. Conclusions: Peripheral and autonomic neuropathies do not invariably coexist in diabetes. In addition, chronic painful neuropathy may be present irrespective of the presence of autonomic neuropathy.

Relationship between plasma sialic acid concentration and microvascular and macrovascular complications in type 1 diabetes: the EURODIAB Complications Study

OBJECTIVE

To test the hypothesis that an increased plasma concentration of sialic acid, a marker of the acute-phase response, is related to the presence of diabetic micro- and macrovascular complications in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We investigated the relationship between plasma sialic acid concentration and nephropathy, retinopathy, neuropathy, and coronary heart disease (CHD) in a cross-sectional survey of 1,369 people with type 1 diabetes. Subjects were participants in the EURODIAB IDDM Complications Study, which involved 31 centers in 16 European countries.

RESULTS

There was a significantly increasing trend of plasma sialic acid with severity of retinopathy (P < 0.001 in men) and with degree of urinary albumin excretion (P < 0.001 men, P < 0.01 women). Plasma sialic acid correlated with increasing plasma creatinine concentration (P < 0.009 men, P < 0.0002 women), and men with neuropathy had a higher plasma sialic acid concentration than those without (P < 0.006). There was no significant correlation between plasma sialic acid and CHD in either sex. Elevated plasma sialic acid concentrations were also associated with several risk factors for diabetic vascular disease: diabetes duration, HbA1c, plasma triglyceride and cholesterol concentrations, waist-to-hip ratio, hypertension and smoking (in men), and low physical exercise (in women). In multiple logistic regression analysis, plasma sialic acid was independently related to proliferative retinopathy and urinary albumin excretion rate in men.

CONCLUSIONS

We conclude that an elevated plasma sialic concentration is strongly related to the presence of microvascular complications in type 1 diabetes, especially retinopathy and nephropathy. Further study of acute-phase response markers and mediators as indicators or predictors of diabetic microvascular complications is therefore justified.

Cardiovascular autonomic neuropathy in insulin-dependent diabetes mellitus: prevalence and estimated risk of coronary heart disease in the general population

OBJECTIVES

The aim of the study was to estimate the prevalence of cardiovascular autonomic neuropathy (CAN) in Type 1 diabetes mellitus in the general population and to assess the relationship between CAN and risk of future coronary heart disease (CHD).

METHODS

The Type 1 diabetes mellitus population in the municipality of Horsens, Denmark, was delineated by the prescription method and a random sample of 120 diabetics aged 40-75 years was recruited. Type 1 diabetes mellitus was registered if fasting C-peptide was below 0.30 nmol L(-1). The E/I ratio was calculated as the mean of the longest R-R interval in expiration divided by the shortest in inspiration during deep breathing at 6 breaths min(-1) and taken to express the degree of CAN. A maximal symptom-limited exercise test was carried out and the VA Prognostic Score, indicating risk of cardiovascular death or non-fatal myocardial infarction, was computed. Additionally, the 10-year risk of CHD was calculated using the Framingham model.

RESULTS

A total of 84 people responded, of whom 71 had Type 1 diabetes mellitus. The E/I ratio was measured in 69 people. The prevalence of CAN expressed as an E/I ratio below the normal 5th percentile was 38%. The E/I ratio was significantly reduced in old age, long duration of diabetes, female gender, high fasting blood glucose, triglyceride, systolic blood pressure and urinary albumin excretion. A high risk of future CHD calculated using the Framingham model was associated with a low E/I ratio (r = -0.39, P = 0.001). Exercise capacity, rise in systolic blood pressure and heart rate were positively correlated with the E/I ratio. A high VA Prognostic Score was correlated with a low E/I ratio (r = - 0.58, P < 0.0005). The risks estimated by the two models were significantly correlated (r = 0.60, P < 0.0005).

CONCLUSION

The prevalence of CAN in the 40-75-year-old Type 1 diabetes mellitus population is estimated to be 38%. CAN is associated with exercise test parameters and a coronary risk factor profile indicating a high risk of future CHD.

Peripheral neuropathy in B6C3F1 mice and SD rats induced by chronic intermittent insulin hypoglycemia

The effects of sustained insulin-induced hypoglycemia on peripheral nerves were examined in 9-10-week old female B6C3F1 mice and 9-10-week old female SD rats. Insulin was administered via osmotic minipumps at a dose of 81 IU/kg/day for 2 consecutive weeks. Mice and rats treated with this high insulin dose showed marked hypoglycemia, resulting in half the normal blood glucose level, hypothermia, impaired motor nerve conduction velocity, and an increased incidence of peripheral nerve lesions, consisting of nerve fiber degeneration characterized by irregular myelin sheaths and axonal atrophy.

Spinal cord stimulation in diabetic lower limb critical ischaemia: transcutaneous oxygen measurement as predictor for treatment success

OBJECTIVES

to evaluate whether transcutaneous oxygen tension (TcpO(2)) measurements could be used as a specific prognostic parameter in selecting diabetic patients for permanent device implantation.

METHODS

sixty consecutive diabetic patients (28 with autonomic neuropathy), classified as Fontaine stage III or IV, underwent spinal cord stimulation (SCS) for ischaemic pain, after failed conservative or surgical treatment. Pedal TcpO(2)on the dorsum of the foot and ankle-pressure Doppler measurements were performed before, and 2 and 4 weeks after implantation.

RESULTS

limb salvage and good pain relief were achieved in 35 patients, while in 12 partial pain relief and limb salvage for at least 6 months were obtained. In 13 patients the method failed and the ischaemic limbs were amputated. Only 3 of the 28 patients with neuropathy had any long-term benefit. Limb salvage was achieved in those patients with a significant increase in TcpO(2)within 2 weeks of stimulation. The stage of the neuropathy was inversely related to the success of SCS therapy. The ankle-brachial pressure index (ABPI) did not change after stimulation.

CONCLUSIONS

diabetic patients with significant increase of TcpO(2)and pain relief during a 2-week test period may be successfully treated by long-term SCS unless they have advanced autonomic neuropathy.

The Greek contribution to diabetes research

Interest in diabetes mellitus research has escalated in Greece during the last decade. This may be attributed to the realization that diabetes is becoming a major problem for the Greek population, the effect of the St Vincent Declaration in passing specific government legislation, and the founding of the National Hellenic Center for the Prevention and Treatment of Diabetes and its Complications. Research areas include epidemiology, etiopathogenesis, glucose metabolism, complications, prevention and treatment of the disease.

Painful diabetic neuropathy

Chronic painful diabetic neuropathy causes symptoms that can last for many years and severely impair the quality of life of affected patients. This review describes the epidemiology, pathophysiology and treatment of chronic neuropathic pain. Particular emphasis is placed on a comprehensive review of the management of painful symptoms through a detailed review of the published literature using a variety of databases particularly Medline and EMBASE.

Quantitative sensory and autonomic testing in male diabetic patients with erectile dysfunction

OBJECTIVE

To correlate abnormalities of nerve fibres in the lower limbs with erectile dysfunction in male diabetic patients, using a range of quantitative sensory and autonomic function tests.

PATIENTS AND METHODS

The study included 68 male diabetic patients with symptomatic erectile dysfunction and 11 matched diabetics without erectile dysfunction; none had clinical evidence of peripheral vascular disease or psychological disorder. Patients were evaluated with a symptom questionnaire based on the Michigan Neuropathy Screening Instrument questionnaire and examined clinically. Sural and peroneal nerve-conduction studies, and quantitative sensory and autonomic tests (vibration, thermal, light-touch thresholds, sensory and autonomic cutaneous axon-reflexes) were used to detect nerve abnormalities in the lower limbs, which were correlated with erectile dysfunction.

RESULTS

Symptoms of neuropathy were more common in the group with male erectile dysfunction (MED), but statistically significant only for neuropathic pain (53% MED, 18% nonMED, P<0.05, chi-square test) and gastroparesis (44% MED, 0% nonMED, P<0.05). Tests of unmyelinated afferents (warming perception and capsaicin-induced sensory axon-reflex vasodilatation) were most often abnormal, sometimes with no other abnormalities on tests or neurological examination. However, abnormality of warm perception was not significantly different between groups (81% MED, 70% nonMED), suggesting that it is a poorer discriminant than abnormal sensory axon-reflex vasodilatation (89% MED, 22% nonMED, P<0.001). The only other significant test difference was decreased sural nerve action potential (70% MED, 22% non-MED, P<0.01).

CONCLUSIONS

There appeared to be preferential involvement of unmyelinated sensory fibres that mediate axon-reflex vasodilatation in the limbs of diabetic patients with erectile dysfunction. This test appears to be a helpful indicator of neurological involvement in erectile dysfunction, and may be used to monitor the effect of new treatments.

Effect of angiotensin-converting-enzyme (ACE) inhibitor trandolapril on human diabetic neuropathy: randomised double-blind controlled trial

BACKGROUND

Diabetes is a common cause of polyneuropathy. The development and progression of nephropathy, retinopathy, and neuropathy are closely related. Angiotensin-converting enzyme (ACE) inhibitors delay progression of both nephropathy and retinopathy. We investigated the effect of ACE inhibition on diabetic neuropathy.

METHODS

We recruited 41 normotensive patients with type I or type II diabetes and mild neuropathy into a randomised double-blind placebo-controlled trial. Changes in the neuropathy symptom and deficit scores, vibration-perception threshold, peripheral-nerve electrophysiology, and cardiovascular autonomic function, were assessed at 6 and 12 months. The primary endpoint was the change in peroneal nerve motor conduction velocity.

FINDINGS

We found no significant difference at baseline for age, HbA1c, blood pressure, or severity of neuropathy between two groups. There was no change in HbA1c over the treatment period. Peroneal motor nerve conduction velocity (p=0.03) and M-wave amplitude (p=0.03) increased, and the F-wave latency (p=0.03) decreased and sural nerve action potential amplitude increased (p=0.04) significantly after 12 months of treatment with trandolapril compared with placebo. Vibration-perception threshold, autonomic function, and the neuropathy symptom and deficit score showed no improvement in either group.

INTERPRETATION

The ACE inhibitor trandolapril may improve peripheral neuropathy in normotensive patients with diabetes. Larger clinical trials are needed to confirm these data before changes to clinical practice can be advocated.

Diabetic neuropathy in Mauritius: prevalence and risk factors

The study of diabetic neuropathy has been primarily in Europids, despite the high prevalence of diabetes in other populations. We set out to ascertain the prevalence of diabetic neuropathy and its risk factors in the island nation of Mauritius. Population surveys were carried out in 1987 and 1992 in Mauritius to establish the prevalence of Type 2 diabetes. In the second survey, vibration perception threshold (VPT) was also measured at the great toe in 847 subjects with diabetes, 204 subjects with impaired glucose tolerance and 127 subjects with normal glucose tolerance. Neuropathy was defined as levels of VPT exceeding the mean plus 2 standard deviations defined separately for three age groups of Mauritian non-diabetic subjects. Risk factors for neuropathy were identified cross sectionally from the 1992 data, and longitudinally from the 1987 data. Neuropathy was detected in 8.3% of the 847 diabetic subjects (12.7%) of those with known diabetes, and 3.6% of those with newly diagnosed diabetes). Logistic regression identified diabetes duration (odds ratio [95% CI]; 1.08 [1.04-1.13] per year, P=0.0002), treatment with insulin or oral hypoglycaemic agents (2.63 [1.36-5.09], P=0.004) and greater height (1.36 [1.19-1.57] per 5 cm, P < 0.001) as risk factors for neuropathy, in the cross sectional analysis. In the longitudinal analysis, diabetes duration (1.11 [1.05-1.18] per year, P=0.001), fasting glucose (1.12 [1.03-1.22] per mmol/l, P=0.01) and height (1.23 [1.03-1.45] per 5 cm, P=0.02) were associated with neuropathy. A lower 2-h plasma insulin was also associated with neuropathy in the longitudinal analysis. The prevalence of diabetic neuropathy in Mauritius is the lowest reported for any population, but the risk factors associated with it are similar to those previously found.

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.

Relation of heart rate variability and serum lipoproteins in type 1 diabetes mellitus and chronic stable angina pectoris

This investigation examines whether serum lipoprotein levels in patients with diabetes mellitus and in those with coronary artery disease are associated with lower heart rate variability (HRV). The study group consisted of 58 subjects divided into 3 groups: normal subjects, chronic stable angina, and type 1 diabetes. Twenty-four-hour ambulatory electrocardiographic recordings were analyzed in the time and frequency domains; standard instantaneous autonomic testing was also performed. On 24-hour ambulatory recordings, patients with chronic stable angina had significantly lower HRV than normals, and diabetics had a more marked reduction in HRV than both normals and anginal patients. When anginal patients and diabetics were stratified by total serum and low-density lipoprotein (LDL) cholesterol levels, diabetics with elevated total and LDL cholesterol had an additional, significant decrease in HRV parameters. No such difference was demonstrated in patients with stable angina. No significant correlations were noted for high-density lipoprotein (HDL) cholesterol, triglycerides, or total cholesterol/HDL ratio and HRV in diabetics or patient with angina. Diabetics with markedly abnormal peripheral reflexes had significantly higher triglycerides and total cholesterol/HDL ratios. Finally, standard tests of autonomic function did not correlate with total, LDL, HDL cholesterol levels, total cholesterol/HDL ratio, or triglycerides. Thus, we found a relation between atherogenic lipid levels and reduced HRV in diabetic patients that has not been previously identified.

Smoking, diabetes and hyperlipidaemia

The epidemiological evidence linking smoking with insulin resistance is considerable. This evidence is even more convincing because there is a dose response relationship between smoking and the risk of non-insulin dependent diabetes (NIDDM). Similarly, there is a time-dependent decrease in risk of NIDDM for those who quit smoking. Insulin resistance (in the form of impaired glucose tolerance, IGT) may precede the development of NIDDM. There is a biochemical basis for the smoking-IGT/NIDDM relationship. Smoking increases the risk of developing diabetic complications like nephropathy, neuropathy and retinopathy Smoking is also an independent risk factor for myocardial infarction and all-cause mortality in NIDDM. Smokers are both insulin resistant and lipid intolerant. Smoking cessation increases circulating high density lipoprotein (HDL) and reduces low density lipoprotein (LDL) levels, despite weight gain. Those providing advice or treatment to improve cardiovascular risk factors should be aware of these smoking-related harmful effects. This is especially true if IGT is underdiagnosed despite the fact that this condition increases the risk of vascular events. Explaining that smoking increases the chance of developing diabetes as well as raising 'blood fat' levels may convince more smokers to quit.

Susceptibility to diabetic neuropathy in patients with insulin dependent diabetes mellitus is associated with a polymorphism at the 5' end of the aldose reductase gene

OBJECTIVES

There is evidence that the polyol pathway is involved in the pathogenesis of diabetic neuropathy. Aldose reductase (ALR2) is the first and rate limiting enzyme of this pathway and recent studies have suggested that polymorphisms in and around the gene are associated with the development of diabetic microvascular disease. The aim was to examine the role of ALR2 in the susceptibility to diabetic neuropathy in patients with insulin dependent diabetes mellitus (IDDM).

METHODS

One hundred and fifty nine British white patients with IDDM and 102 normal healthy controls were studied using the polymerase chain reaction to test for a highly polymorphic microsatellite marker 2.1 kilobase (kb) upstream of the initiation site of the ALR2 gene.

RESULTS

Seven alleles were detected (Z-6, Z-4, Z-2, Z, Z+2, Z+4, and Z+6). There was a highly significant decrease in the frequency of the Z+2 allele in those patients with overt neuropathy compared with those with no neuropathy after 20 years duration of diabetes (14.1% v 38.2%, chi2 =17.3, p<0.00001). A similar difference was also found between the neuropathy group and those patients who have had diabetes for < five years with no overt neuropathy (14.1% v 30.2%, chi2=9.0, p<0.0025). The neuropathy group also had a significant decrease in the frequency of the Z/Z+2 genotype compared with those patients who have no neuropathy after 20 years duration of diabetes (14.0% v 44.7%, chi2=13.0, p<0.0005).

CONCLUSION

These results suggest that the aldose reductase gene is intimately involved in the pathogenesis of diabetic neuropathy.

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.

Electrical spinal-cord stimulation for painful diabetic peripheral neuropathy

BACKGROUND

Conventional treatment for painful peripheral diabetic neuropathy is largely symptomatic and often ineffective, with unacceptable side-effects. We tested electrical spinal-cord stimulation for the management of chronic neuropathic pain.

METHODS

Ten diabetic patients who did not respond to conventional treatment (mean age 51 [SD 9.3] years, six with type II diabetes, mean duration of diabetes 12 [6.3] years, mean duration of neuropathy 5 [2.1] years) were studied. The electrode was implanted in the thoracic/lumbar epidural space. Immediate neuropathic pain relief was assessed by visual analogue scale (VAS) after connecting the electrode, in a random order, to a percutaneous electrical stimulator or to a placebo stimulator. Exercise tolerance was assessed on a treadmill.

FINDINGS

Eight subjects had statistically significant pain relief with the electrical stimulator (p < 0.02) and were therefore converted to a permanent system. Statistically significant relief of both background and peak neuropathic pain was achieved at 3 months (n = 7, p = 0.016), at 6 months (n = 7, p = 0.03), and at the end of the study (14 months, n = 7, background pain p = 0.06, peak pain p = 0.03). One patient died 2 months after the start of the study of unrelated cause while continuing to benefit from treatment and another patient ceased to benefit at 4 months. McGill pain questionnaire scores with the stimulator turned off did not change significantly from baseline scores, indicating that the severity of the underlying pain was unaltered. However, with the stimulator turned on, there was a statistically significant (p < 0.05) improvement in all four components of the score, by the end of the study. At the end of the study, six patients continued to gain significant pain relief and used the stimulator as the sole treatment for their neuropathic pain. For example, median background and peak pain scores at the end of study, were, respectively, 77 and 81 with the stimulator off and 23 and 20 with the stimulator on. Exercise tolerance significantly improved at 3 months (n = 7, median % increase 85 [IQR, 62-360], p = 0.015) and at 6 months (n = 6, 163 [61-425], p = 0.0007). Electrophysiological tests, vibration perception-threshold, and glycaemic control were unchanged.

INTERPRETATION

Electrical spinal-cord stimulation offers a new and effective way of relieving chronic diabetic neuropathic pain and improves exercise tolerance. The technique should be considered in patients with neuropathic pain who do not respond to conventional treatment.