Where does spinal cord stimulation fit into the international guidelines for refractory painful diabetic neuropathy? a consensus statement

BACKGROUND

Although pharmacotherapy with anticonvulsants and/or antidepressants can be effective for many people with painful diabetic neuropathy (PDN), albeit with frequent side-effects, a critical juncture occurs when neuropathic pain no longer responds to standard first- and second-step mono- and dual therapy and becomes refractory. Subsequent to these pharmacotherapeutic approaches, third-line treatment options for PDN may include opioids (short-term), capsaicin 8% patches, and spinal cord stimulation (SCS).

AIM

This document summarizes consensus recommendations regarding appropriate treatment for refractory peripheral diabetic neuropathy (PDN), based on outcomes from an expert panel convened on December 10, 2022, as part of the Worldwide Initiative for Diabetes Education Virtual Global Summit, "Advances in the Management of Painful Diabetic Neuropathy."

PARTICIPANTS

Nine attendees, eminent physicians and academics, comprising six diabetes specialists, two pain specialists, and one health services expert.

EVIDENCE

For individuals with refractory PDN, opioids are a high-risk option that do not provide a long-term solution and should not be used. For appropriately selected individuals, SCS is an effective, safe, and durable treatment option. In particular, high-frequency (HF) SCS (10 kHz) shows strong efficacy and improves quality of life. To ensure treatment success, strict screening criteria should be used to prioritize candidates for SCS.

CONSENSUS PROCESS

Each participant voiced their opinion after reviewing available data, and a verbal consensus was reached during the meeting.

CONCLUSION

Globally, the use of opioids should rarely be recommended for refractory, severe PDN. Based on increasing clinical evidence, SCS, especially HF-SCS, should be considered as a treatment for PDN that is not responsive to first- or second-line monotherapy/dual therapy.

Diabetes and Covid-19: Diabetes research funding and support during the pandemic

AIMS

Between late 2020 and early 2022, EURADIA undertook a survey of organisations and individuals supporting or working in the field of diabetes research with the aim of understanding better the impact of the Covid-19 pandemic on funding for diabetes research in Europe.

METHODS

Information was collected via online survey augmented in some cases by face-to-face interviews.

RESULTS

Findings were mixed but the majority of those responding suggested a moderate impact of the pandemic on diabetes research activity. Many respondents reported a reduction in funding during the pandemic and many of those involved in clinical research experienced a reduction in research clinicians' availability for diabetes research as they were redeployed to Covid-19 patient care. It was frequently reported that the impact might not be fully appreciated until several years after the end of the pandemic.

CONCLUSIONS

This preliminary survey suggests there may be a significant impact of the pandemic on all aspects of diabetes research and that a more detailed follow-up on the impact of the pandemic on funding of diabetes research should be carried out in the future.

Correlates of self-rated health in people with diabetic peripheral neuropathy: a longitudinal study

AIM

Self-rated health, a measure of self-reported general health, is a robust predictor of morbidity and mortality in various populations, including persons with diabetes. This study examines correlates of self-rated health in adults with diabetic peripheral neuropathy (DPN).

METHODS

Participants recruited from the UK and USA (n = 295; mean (± sd) age: 61.5 ± 10.7 years; 69% male; 71% type 2 diabetes) rated their health at baseline and 18 months. DPN severity was assessed using the neuropathy disability score and the vibration perception threshold. Validated self-report measures assessed neuroticism, DPN-symptoms of pain, unsteadiness and reduced sensation in feet, DPN-related limitations in daily activities, DPN-specific emotional distress and symptoms of depression.

RESULTS

In the fully adjusted baseline model, younger age, presence of cardiovascular disease and higher depression symptom scores showed likely clinically meaningful independent associations with worse health ratings. Being at the UK study site and presence of nephropathy indicated potentially meaningful independent associations with lower baseline health ratings. These predictors were largely consistent in their association with health ratings at 18 months.

CONCLUSION

Results identify independent correlates of health ratings among adults with DPN. Future research should investigate the clinical implications of associations and examine changes in these variables over time and potential effects on changes in health perceptions. If these associations reflect causal pathways, our results may guide interventions to target issues that are likely to have an impact on subjectively experienced health as an important patient-reported outcome in DPN care.

Altered accelerator pedal control in a driving simulator in people with diabetic peripheral neuropathy

AIM

To investigate whether the sensory-motor impairment attributable to diabetic peripheral neuropathy would affect control of the accelerator pedal during a driving simulator task.

METHODS

A total of 32 active drivers, 11 with diabetic peripheral neuropathy (mean ± sd age 67±5.0 years), 10 with diabetes but no neuropathy (diabetes group; mean ± sd age 62±10 years), and 11 healthy individuals without diabetes (healthy group; mean ± sd age 60±11 years), undertook a test on a dynamometer to assess ankle plantar flexor muscle strength and ankle joint proprioception function of the right leg, in addition to a driving simulator task. The following variables were measured: maximal ankle plantar flexor muscle strength; speed of strength generation (Nm/s); and ankle joint proprioception (ankle repositioning error, degrees). In the driving simulator task, driving speed (mph), accelerator pedal signal (degrees) and the duration of specific 'loss-of-control events' (s) were measured during two drives (Drive 1, Drive 2).

RESULTS

Participants with diabetic peripheral neuropathy had a lower speed of strength generation (P<0.001), lower maximal ankle plantar flexor muscle strength (P<0.001) and impaired ankle proprioception (P=0.034) compared to healthy participants. The diabetic peripheral neuropathy group drove more slowly compared with the healthy group (Drive 1 P=0.048; Drive 2 P=0.042) and showed marked differences in the use of the accelerator pedal compared to both the diabetes group (P=0.010) and the healthy group (P=0.002). Participants with diabetic peripheral neuropathy had the longest duration of loss-of-control events, but after one drive, this was greatly reduced (P=0.023).

CONCLUSIONS

Muscle function, ankle proprioception and accelerator pedal control are all affected in people with diabetic peripheral neuropathy, adversely influencing driving performance, but potential for improvement with targeted practice remains possible.

Latent autoimmune diabetes of adulthood (LADA) is associated with small fibre neuropathy

AIM

To assess if latent autoimmune diabetes of adulthood (LADA) is associated with small fibre neuropathy.

METHODS

Participants with LADA (n=31), Type 2 diabetes (n=31) and healthy control participants without diabetes (n=31) underwent a detailed assessment of neurologic deficits, quantitative sensory testing, electrophysiology, skin biopsy and corneal confocal microscopy.

RESULTS

The groups were matched for age (healthy control without diabetes: 53.5±9.1 vs. Type 2 diabetes: 58.0±6.5 vs. LADA: 53.2±11.6 years), duration of diabetes (Type 2 diabetes: 10.0±8.3 vs. LADA: 11.0±9.1 years) and blood pressure. However, BMI (P=0.01) and triglycerides (P=0.0008) were lower and HbA_1c (P=0.0005), total cholesterol (P=0.01) and HDL (P=0.002) were higher in participants with LADA compared with Type 2 diabetes. Peroneal motor nerve conduction velocity (P=0.04) and sural sensory nerve conduction velocity (P=0.008) were lower in participants with latent autoimmune diabetes in adults compared with Type 2 diabetes. Intra-epidermal nerve fibre density (P=0.008), corneal nerve fibre density (P=0.003) and corneal nerve branch density (P=0.006) were significantly lower in participants with LADA compared with Type 2 diabetes. There were no significant differences in the other neuropathy parameters.

CONCLUSIONS

Despite comparable age and duration of diabetes, participants with LADA demonstrate more severe neuropathy and particularly small fibre neuropathy, compared with participants with Type 2 diabetes.

Vertical displacement of the centre of mass during walking in people with diabetes and diabetic neuropathy does not explain their higher metabolic cost of walking

People with diabetes display biomechanical gait alterations compared to controls and have a higher metabolic cost of walking (CoW), but it remains unknown whether differences in the vertical displacement of the body centre of mass (CoM) may play a role in this higher CoW. The aim of this study was to investigate vertical CoM displacement (and step length as a potential underpinning factor) as an explanatory factor in the previously observed increased CoW with diabetes. Thirty-one non-diabetic controls (Ctrl); 22 diabetic patients without peripheral neuropathy (DM) and 14 patients with moderate/severe Diabetic Peripheral Neuropathy (DPN), underwent gait analysis using a motion analysis system and force plates while walking at a range of matched speeds between 0.6 and 1.6 m/s. Vertical displacement of the CoM was measured over the gait cycle, and was not different in either diabetes patients with or without diabetic peripheral neuropathy compared to controls across the range of matched walking speeds examined (at 1 m/s: Ctrl: 5.59 (SD: 1.6), DM: 5.41 (1.63), DPN: 4.91 (1.66) cm; p > 0.05). The DPN group displayed significantly shorter steps (at 1 m/s: Ctrl: 69, DM: 67, DPN: 64 cm; p > 0.05) and higher cadence (at 1 m/s: Ctrl: 117 (SD1.12), DM: 119 (1.08), DPN: 122 (1.25) steps per minute; p > 0.05) across all walking speeds compared to controls. The vertical CoM displacement is therefore unlikely to be a factor in itself that contributes towards the higher CoW observed recently in people with diabetic neuropathy. The higher CoW in patients with diabetes may not be explained by the CoM displacement, but rather may be more related to shorter step lengths, increased cadence and the associated increased internal work and higher muscle forces developed by walking with more flexed joints.

Altered Achilles tendon function during walking in people with diabetic neuropathy: implications for metabolic energy saving

The Achilles tendon (AT) has the capacity to store and release elastic energy during walking, contributing to metabolic energy savings. In diabetes patients, it is hypothesized that a stiffer Achilles tendon may reduce the capacity for energy saving through this mechanism, thereby contributing to an increased metabolic cost of walking (CoW). The aim of this study was to investigate the effects of diabetes and diabetic peripheral neuropathy (DPN) on the Achilles tendon and plantarflexor muscle-tendon unit behavior during walking. Twenty-three nondiabetic controls (Ctrl); 20 diabetic patients without peripheral neuropathy (DM), and 13 patients with moderate/severe DPN underwent gait analysis using a motion analysis system, force plates, and ultrasound measurements of the gastrocnemius muscle, using a muscle model to determine Achilles tendon and muscle-tendon length changes. During walking, the DM and particularly the DPN group displayed significantly less Achilles tendon elongation (Ctrl: 1.81; DM: 1.66; and DPN: 1.54 cm), higher tendon stiffness (Ctrl: 210; DM: 231; and DPN: 240 N/mm), and higher tendon hysteresis (Ctrl: 18; DM: 21; and DPN: 24%) compared with controls. The muscle fascicles of the gastrocnemius underwent very small length changes in all groups during walking (~0.43 cm), with the smallest length changes in the DPN group. Achilles tendon forces were significantly lower in the diabetes groups compared with controls (Ctrl: 2666; DM: 2609; and DPN: 2150 N). The results strongly point toward the reduced energy saving capacity of the Achilles tendon during walking in diabetes patients as an important factor contributing to the increased metabolic CoW in these patients. NEW & NOTEWORTHY From measurements taken during walking we observed that the Achilles tendon in people with diabetes and particularly people with diabetic peripheral neuropathy was stiffer, was less elongated, and was subject to lower forces compared with controls without diabetes. These altered properties of the Achilles tendon in people with diabetes reduce the tendon's energy saving capacity and contribute toward the higher metabolic energy cost of walking in these patients.

Altered walking strategy and increased unsteadiness in participants with impaired glucose tolerance and Type 2 diabetes relates to small-fibre neuropathy but not vitamin D deficiency

AIMS

To investigate alterations in walking strategy and dynamic sway (unsteadiness) in people with impaired glucose tolerance and people with Type 2 diabetes in relation to severity of neuropathy and vitamin D levels.

METHODS

A total of 20 people with Type 2 diabetes, 20 people with impaired glucose tolerance and 20 people without either Type 2 diabetes or impaired glucose tolerance (control group) underwent gait analysis using a motion analysis system and force platforms, and detailed assessment of neuropathy and serum 25 hydroxy-vitamin D levels.

RESULTS

Ankle strength (P = 0.01) and power (P = 0.003) during walking and walking speed (P = 0.008) were preserved in participants with impaired glucose tolerance but significantly lower in participants with Type 2 diabetes compared with control participants; however, step width (P = 0.005) and dynamic medio-lateral sway (P = 0.007) were significantly higher and posterior maximal movement (P = 0.000) was lower in participants with impaired glucose tolerance, but preserved in those with Type 2 diabetes compared with the control group. Dynamic medio-lateral sway correlated with corneal nerve fibre length (P = 0.001) and corneal nerve branch density (P = 0.001), but not with vibration perception threshold (P = 0.19). Serum 25 hydroxy-vitamin D levels did not differ significantly among the groups (P = 0.10) and did not correlate with any walking variables or measures of dynamic sway.

CONCLUSIONS

Early abnormalities in walking strategy and dynamic sway were evident in participants with impaired glucose tolerance, whilst there was a reduction in ankle strength, power and walking speed in participants with Type 2 diabetes. Unsteadiness correlated with small-, but not large-fibre neuropathy and there was no relationship between vitamin D levels and walking variables.

Distal lower limb strength is reduced in subjects with impaired glucose tolerance and is related to elevated intramuscular fat level and vitamin D deficiency

AIM

To quantify muscle strength and size in subjects with impaired glucose tolerance (IGT) in relation to intramuscular non-contractile tissue, the severity of neuropathy and vitamin D level.

METHODS

A total of 20 subjects with impaired glucose tolerance and 20 control subjects underwent assessment of strength and size of knee extensor, flexor and ankle plantar and dorsi-flexor muscles, as well as quantification of intramuscular non-contractile tissue and detailed assessment of neuropathy and serum 25-hydroxy vitamin D levels.

RESULTS

In subjects with impaired glucose tolerance, proximal knee extensor strength (P = 0.17) and volume (P = 0.77), and knee flexor volume (P = 0.97) did not differ from those in control subjects. Ankle plantar flexor strength was significantly lower (P = 0.04) in the subjects with impaired glucose tolerance, with no difference in ankle plantar flexor (P = 0.62) or dorsiflexor volume (P = 0.06) between groups. Intramuscular non-contractile tissue level was significantly higher in the ankle plantar flexors and dorsiflexors (P = 0.03) of subjects with impaired glucose tolerance compared with control subjects, and it correlated with the severity of neuropathy. Ankle plantar flexor muscle strength correlated significantly with corneal nerve fibre density (r = 0.53; P = 0.01), a sensitive measure of small fibre neuropathy, and was significantly lower in subjects with vitamin D deficiency (P = 0.02).

CONCLUSIONS

People with impaired glucose tolerance have a significant reduction in distal but not proximal leg muscle strength, which is not associated with muscle atrophy, but with increased distal intramuscular non-contractile tissue, small fibre neuropathy and vitamin D deficiency.

People with diabetic peripheral neuropathy display a decreased stepping accuracy during walking: potential implications for risk of tripping

AIM

To examine the stepping accuracy of people with diabetes and diabetic peripheral neuropathy.

METHODS

Fourteen patients with diabetic peripheral neuropathy (DPN), 12 patients with diabetes but no neuropathy (D) and 10 healthy non-diabetic control participants (C). Accuracy of stepping was measured whilst the participants walked along a walkway consisting of 18 stepping targets. Preliminary data on visual gaze characteristics were also captured in a subset of participants (diabetic peripheral neuropathy group: n = 4; diabetes-alone group: n = 4; and control group: n = 4) during the same task.

RESULTS

Patients in the diabetic peripheral neuropathy group, and patients in the diabetes-alone group were significantly less accurate at stepping on targets than were control subjects (P < 0.05). Preliminary visual gaze analysis identified that patients diabetic peripheral neuropathy were slower to look between targets, resulting in less time being spent looking at a target before foot-target contact.

CONCLUSIONS

Impaired motor control is theorized to be a major factor underlying the changes in stepping accuracy, and potentially altered visual gaze behaviour may also play a role. Reduced stepping accuracy may indicate a decreased ability to control the placement of the lower limbs, leading to patients with neuropathy potentially being less able to avoid observed obstacles during walking.

Resistance exercise training increases lower limb speed of strength generation during stair ascent and descent in people with diabetic peripheral neuropathy

AIM

To examine the effects of a 16-week resistance exercise training intervention on the speed of ankle and knee strength generation during stair ascent and descent, in people with neuropathy.

METHODS

A total of 43 people: nine with diabetic peripheral neuropathy, 13 with diabetes but no neuropathy and 21 healthy control subjects ascended and descended a custom-built staircase. The speed at which ankle and knee strength were generated, and muscle activation patterns of the ankle and knee extensor muscles were analysed before and after a 16-week intervention period.

RESULTS

Ankle and knee strength generation during both stair ascent and descent were significantly higher after the intervention than before the intervention in the people with diabetes who undertook the resistance exercise intervention (P < 0.05). Although muscle activations were altered by the intervention, there were no observable patterns that underpinned the observed changes.

CONCLUSIONS

The increased speed of ankle and knee strength generation observed after the intervention would be expected to improve stability during the crucial weight acceptance phase of stair ascent and descent, and ultimately contribute towards reducing the risk of falling. Improvements in muscle strength as a result of the resistance exercise training intervention are likely to be the most influential factor for increasing the speed of strength generation. It is recommended that these exercises could be incorporated into a multi-faceted exercise programme to improve safety in people with diabetes and neuropathy.

The diabetic foot in 2015: an overview

In 2015, it can be said that the diabetic foot is no longer the Cinderella of diabetic complications. Thirty years ago there was little evidence-based research taking place on the diabetic foot, and there were no international meetings addressing this topic. Since then, the biennial Malvern Diabetic Foot meetings started in 1986, the American Diabetes Association founded their Foot Council in 1987, and the European Association for the Study of Diabetes established a Foot Study Group in 1998. The first International Symposium on the Diabetic Foot in The Netherlands was convened in 1991, and this was soon followed by the establishment of the International Working Group on the Diabetic Foot that has produced useful guidelines in several areas of investigation and the management of diabetic foot problems. There has been an exponential rise in publications on diabetic foot problems in high impact factor journals, and a comprehensive evidence-base now exists for many areas of treatment. Despite the extensive evidence available, it, unfortunately, remains difficult to demonstrate that most types of education are efficient in reducing the incidence of foot ulcers. However, there is evidence that education as part of a multi-disciplinary approach to diabetic foot ulceration plays a pivotal role in incidence reduction. With respect to treatment, strong evidence exists that offloading is the best modality for healing plantar neuropathic foot ulcers, and there is also evidence from two randomized controlled trials to support the use of negative-pressure wound therapy in complex post-surgical diabetic foot wounds. Hyperbaric oxygen therapy exhibits the same evidence level and strength of recommendation. International guidelines exist on the management of infection in the diabetic foot. Many randomized trials have been performed, and these have shown that the agents studied generally produced comparable results, with the exception of one study in which tigecycline was shown to be clinically inferior to ertapenem ± vancomycin. Similarly, there are numerous types of wound dressings that might be used in treatment and which have shown efficacy, but no single type (or brand) has shown superiority over others. Peripheral artery disease is another major contributory factor in the development of ulceration, and its presence is a strong predictor of non-healing and amputation. Despite the proliferation of endovascular procedures in addition to open revascularization, many patients continue to suffer from severely impaired perfusion and exhaust all treatment options. Finally, the question of the true aetiopathogenesis of Charcot neuroarthropathy remains enigmatic, although much work is currently being undertaken in this area. In this area, it is most important to remember that a clinically uninfected, warm, insensate foot in a diabetic patient should be considered as a Charcot foot until proven otherwise, and, as such, treated with offloading, preferably in a cast.

Is the metabolic cost of walking higher in people with diabetes?

People with diabetes walk slower and display biomechanical gait alterations compared with controls, but it remains unknown whether the metabolic cost of walking (CoW) is elevated. The aim of this study was to investigate the CoW and the lower limb concentric joint work as a major determinant of the CoW, in patients with diabetes and diabetic peripheral neuropathy (DPN). Thirty-one nondiabetic controls (Ctrl), 22 diabetic patients without peripheral neuropathy (DM), and 14 patients with moderate/severe DPN underwent gait analysis using a motion analysis system and force plates and treadmill walking using a gas analyzer to measure oxygen uptake. The CoW was significantly higher particularly in the DPN group compared with controls and also in the DM group (at selected speeds only) compared with controls, across a range of matched walking speeds. Despite the higher CoW in patients with diabetes, concentric lower limb joint work was significantly lower in DM and DPN groups compared with controls. The higher CoW is likely due to energetic inefficiencies associated with diabetes and DPN reflecting physiological and biomechanical characteristics. The lower concentric joint work in patients with diabetes might be a consequence of kinematic gait alterations and may represent a natural strategy aimed at minimizing the CoW.

Deep wound cultures correlate well with bone biopsy culture in diabetic foot osteomyelitis

BACKGROUND

Osteomyelitis is a major complication in patients with diabetic foot ulceration. Accurate pathogenic identification of organisms can aid the clinician to a specific antibiotic therapy thereby preventing the need for amputation.

METHODS

All diabetic patients with bone biopsy-confirmed osteomyelitis were included into the study: biopsies were performed either during surgical removal of infected bone or percutaneously under guided fluoroscopy through non-infected tissue. The depth and extent of the ulcer was assessed using a sterile blunt metal probe. Deep wound cultures were taken from the wound base after sharp debridement.

RESULTS

Of 66 cases of suspected osteomyelitis in 102 joints, 34 patients had both bone biopsies and deep wound cultures over the study period. Thirty two of 34 (94%), had a history of preceding foot ulceration, and in 25 of the cases a positive probe to bone test was recorded. In a high proportion of patients, at least one similar organism was isolated from both the deep wound culture and bone biopsy procedures (25 of 34 cases, 73.5%, p<0.001). When organisms were isolated from both wound cultures and bone biopsies, the identical strain was identified in both procedures in a significant proportion of cases (16 of 25 cases, 64%, p<0.001, total sample analysis in 16 of 34 cases, 47%).

CONCLUSIONS

Deep wound cultures correlate well with osseous cultures and provide a sensitive method in assessing and targeting likely pathogens that cause osseous infections. This will help aid the clinician in guiding antibiotic therapy in centers where bone biopsies may not be readily available.

A simple new non-invasive sweat indicator test for the diagnosis of diabetic neuropathy

A simple non-invasive indicator test (Neuropad(®)) has been developed for the assessment of sweating and, hence, cholinergic innervation in the diabetic foot. The present review summarizes current knowledge on this diagnostic test. The diagnostic ability of this test is based on a colour change from blue to pink at 10 min, with excellent reproducibility, which lends itself to patient self-examination. It has a high sensitivity (65.1-100%) and negative predictive value (63-100%), with moderate specificity (32-78.5%) and positive predictive value (23.3-93.2%) for the diagnosis of diabetic peripheral neuropathy. It also has moderate to high sensitivity (59.1-89%) and negative predictive value (64.7-91%), but low to moderate specificity (27-78%) and positive predictive value (24-48.6%) for the diagnosis of diabetic cardiac autonomic neuropathy. There are some data to suggest that Neuropad can detect early diabetic neuropathy, but this needs further evaluation. It remains to be established whether this test can predict foot ulceration and amputation, thereby contributing to the identification of high-risk patients.

A new paradigm for improved co-ordination and efficacy of European biomedical research: taking diabetes as a model

Today, European biomedical and health-related research is insufficiently well funded and is fragmented, with no common vision, less-than-optimal sharing of resources, and inadequate support and training in clinical research. Improvements to the competitiveness of European biomedical research will depend on the creation of new infrastructures that must be dynamic and free of bureaucracy, involve all stakeholders and facilitate faster delivery of new discoveries from bench to bedside. Taking diabetes research as the model, a new paradigm for European biomedical research is presented, which offers improved co-ordination and common resources that will benefit both academic and industrial clinical research. This includes the creation of a European Council for Health Research, first proposed by the Alliance for Biomedical Research in Europe, which will bring together and consult with all health stakeholders to develop strategic and multidisciplinary research programmes addressing the full innovation cycle. A European Platform for Clinical Research in Diabetes is proposed by the Alliance for European Diabetes Research (EURADIA) in response to the special challenges and opportunities presented by research across the European region, with the need for common standards and shared expertise and data.

A pocket-sized disposable device for testing the integrity of sensation in the outpatient setting

AIMS

To compare the Ipswich Touch Test and the VibraTip with the Neuropathy Disability Score and the vibration perception threshold for detecting the 'at-risk' foot.

METHODS

We directly compared the Ipswich Touch Test and the VibraTip with both the Neuropathy Disability Score ≥ 6 and the vibration perception threshold ≥ 25 V indicating 'at-risk' feet in 83 individuals.

RESULTS

The vibration perception threshold and Neuropathy Disability Score tests exhibited almost perfect agreement with each other (P < 0.001). The VibraTip and Ipswich Touch Test results were identical (P < 0.001). The VibraTip and Ipswich Touch Test results also exhibited almost perfect agreement with the vibration perception threshold (P < 0.001) and the Neuropathy Disability Score (P < 0.001).

CONCLUSIONS

These two simple and efficient tests are easy to teach, reliable and can be used in any setting, and neither requires an external power source. We conclude that both the VibraTip and the Ipswich Touch Test are reliable and sensitive tests for identifying the 'high-risk' foot.

Corneal confocal microscopy detects improvement in corneal nerve morphology with an improvement in risk factors for diabetic neuropathy

AIM

We have assessed whether corneal confocal microscopy can be used to detect alterations in nerve morphology following an improvement in risk factors associated with diabetic neuropathy.

METHODS

Twenty-five patients with diabetes with mild to moderate neuropathy and 18 control subjects underwent corneal confocal microscopy to quantify corneal nerve fibre (density, branch density, length and tortuosity) at baseline and after 24 months from first visit. This was not planned as an intervention trial and was simply an observational follow-up.

RESULTS

At baseline, nerve fibre density (18.8 ± 2.1 vs. 46.0 ± 3.8 number/mm(2), P = 0.001), nerve branch density (6.9 ± 1.5 vs. 35.6 ± 6.7 number/mm(2), P < 0.0001), nerve fibre length (8.3 ± 0.9 vs. 13.5 ± 0.8 mm/mm(2), P < 0.0001) and nerve fibre tortuosity (19.8 ± 1.6 vs. 22.7 ± 2.2, P < 0.05) were significantly lower in patients with diabetes than in control subjects. At follow-up, glycaemic control (HbA(1c) 64 ± 3 to 58 ± 2 mmol/mol, P = 0.08), total cholesterol (4.9 ± 0.2 to 4.2 ± 0.2 mmol/l, P = 0.01), systolic blood pressure (145.8 ± 4.9 to 135.9 ± 3.7 mmHg, P = 0.09) and diastolic blood pressure (77.8 ± 2.7 to 70.8 ± 2.5, P = 0.03) improved. Nerve fibre density (24.1 ± 2.0, P = 0.05), nerve branch density (11.1 ± 1.3, P < 0.01) and nerve fibre tortuosity (22.6 ± 1.5, P = 0.05) increased significantly, with no change in nerve fibre length (8.4 ± 0.5). Improvement in nerve fibre density correlated significantly with the improvement in HbA(1c) (r = -0.51, P = 0.008). Via four multifactorial regressions, this confirms the negative association between HbA(1c) and nerve fibre density (P = 0.02).

CONCLUSIONS

This study shows that corneal confocal microscopy may be employed in longitudinal studies to assess progression of human diabetic neuropathy and also supports the hypothesis that improvements in risk factors for diabetic neuropathy, in particular HbA(1c) , may lead to morphological repair of nerve fibres.

Painful diabetic peripheral neuropathy: consensus recommendations on diagnosis, assessment and management

Painful diabetic peripheral neuropathy (DPN) is common, is associated with significant reduction in quality of life and poses major treatment challenges to the practising physician. Although poor glucose control and cardiovascular risk factors have been proven to contribute to the aetiology of DPN, risk factors specific for painful DPN remain unknown. A number of instruments have been tested to assess the character, intensity and impact of painful DPN on quality of life, activities of daily living and mood. Management of the patient with DPN must be tailored to individual requirements, taking into consideration the co-morbidities and other factors. Pharmacological agents with proven efficacy for painful DPN include tricyclic anti-depressants, the selective serotonin and noradrenaline re-uptake inhibitors, anti-convulsants, opiates, membrane stabilizers, the anti-oxidant alpha-lipoic acid and topical agents including capsaicin. Current first-line therapies for painful DPN include tricyclic anti-depressants, the serotonin and noradrenaline re-uptake inhibitor duloxetine and the anti-convulsants pregabalin and gabapentin. When prescribing any of these agents, other co-morbidities and costs must be taken into account. Second-line approaches include the use of opiates such as synthetic opioid tramadol, morphine and oxycodone-controlled release. There is a limited literature with regard to combination treatment. In extreme cases of painful DPN unresponsive to pharmacotherapy, occasional use of electrical spinal cord stimulation might be indicated. There are a number of unmet needs in the therapeutic management of painful DPN. These include the need for randomized controlled trials with active comparators and data on the long-term efficacy of agents used, as most trials have lasted for less than 6 months. Finally, there is a need for appropriately designed studies to investigate non-pharmacological approaches.

Depression predicts first but not recurrent diabetic foot ulcers

AIMS/HYPOTHESIS

This study examined the relationship between symptoms of depression and the development of diabetic foot ulcers.

METHODS

Participants were 333 patients (71% male; mean age 62 years; 73% with type 2 diabetes) with diabetic peripheral neuropathy (DPN), but without peripheral vascular disease (PVD). Severity of DPN and the presence of PVD were assessed by clinical examination. Depression, other diabetes complications and foot self-care were assessed by self-report. Cox regression tested whether depression was an independent predictor of foot ulceration over 18 months, whether this relationship was moderated by foot ulcer history, and whether foot self-care mediated this relationship.

RESULTS

During follow-up, 63 patients developed a foot ulcer. Those with prior foot ulcers had more than four-fold greater risk of subsequent foot ulceration compared with those without a history of foot ulcer. A significant interaction effect showed that depression was significantly related to the development of first but not recurrent foot ulcers. This relationship was independent of biological risk factors. In the final model, each standard deviation increase in depression symptoms was significantly associated with increased risk of developing first foot ulcers (HR 1.68, 95% CI 1.20-2.35), while foot self-care was associated with lower risk (HR 0.61, 95% CI 0.40-0.94). Foot self-care did not mediate the relationship between depression and foot ulceration.

CONCLUSIONS/INTERPRETATION

These data suggest that depression is associated with increased risk of first foot ulcers in DPN patients and that this relationship is independent of biological risk factors and foot self-care. Interventions that target depression and foot self-care before the development of foot ulcers may maximise the likelihood of successful prevention of foot ulceration.

Increased Langerhan cell density and corneal nerve damage in diabetic patients: role of immune mechanisms in human diabetic neuropathy

AIM/HYPOTHESIS

Immune mechanisms have been proposed to play a role in the development of diabetic neuropathy. We employed in vivo corneal confocal microscopy (CCM) to quantify the presence and density of Langerhans cells (LCs) in relation to the extent of corneal nerve damage in Bowman's layer of the cornea in diabetic patients.

METHODS

128 diabetic patients aged 58 ± 1 yrs with a differing severity of neuropathy based on Neuropathy Deficit Score (NDS-4.7 ± 0.28) and 26 control subjects aged 53 ± 3 yrs were examined. Subjects underwent a full neurological evaluation, evaluation of corneal sensation with non-contact corneal aesthesiometry (NCCA) and corneal nerve morphology using corneal confocal microscopy (CCM).

RESULTS

The proportion of individuals with LCs was significantly increased in diabetic patients (73.8%) compared to control subjects (46.1%), P = 0.001. Furthermore, LC density (no/mm(2)) was significantly increased in diabetic patients (17.73 ± 1.45) compared to control subjects (6.94 ± 1.58), P = 0.001 and there was a significant correlation with age (r = 0.162, P = 0.047) and severity of neuropathy (r = -0.202, P = 0.02). There was a progressive decrease in corneal sensation with increasing severity of neuropathy assessed using NDS in the diabetic patients (r = 0.414, P = 0.000). Corneal nerve fibre density (P < 0.001), branch density (P < 0.001) and length (P < 0.001) were significantly decreased whilst tortuosity (P < 0.01) was increased in diabetic patients with increasing severity of diabetic neuropathy.

CONCLUSION

Utilising in vivo corneal confocal microscopy we have demonstrated increased LCs in diabetic patients particularly in the earlier phases of corneal nerve damage suggestive of an immune mediated contribution to corneal nerve damage in diabetes.

Effect of L-arginine on the microcirculation in the neuropathic diabetic foot in Type 2 diabetes mellitus: a double-blind, placebo-controlled study

OBJECTIVE

To investigate the effect of L-arginine on endothelial function, transcutaneous oxygen and clinical neuropathy in patients with peripheral neuropathy as a result of diabetes.

RESEARCH DESIGN AND METHODS

Thirty diabetic patients with peripheral neuropathy were randomized to receive L-arginine (3 g three times daily) or placebo (3 g three times daily) for 3 months. All patients had foot microcirculation and foot transcutaneous oxygen pressure (TcPO(2)), neuropathy disability score (NDS) and vibration perception threshold (VPT) assessed at baseline and follow-up.

RESULTS

No difference was observed in endothelium-dependent and -independent vasodilation, TcPO(2), NDS and VPT.

CONCLUSIONS

L-arginine has no effect on endothelial dysfunction, TcPO(2) and clinical neuropathy.

Predictors of depressive symptoms in persons with diabetic peripheral neuropathy: a longitudinal study

AIMS/HYPOTHESIS

The aim of the study was to determine whether diabetic peripheral neuropathy (DPN) is a risk factor for depressive symptoms and examine the potential mechanisms for this relationship.

METHODS

This longitudinal study (9 and 18 month follow-up) of 338 DPN patients (mean age 61 years; 71% male; 73% type 2 diabetes) examined the temporal relationships between DPN severity (mean +/- SD; neuropathy disability score [NDS], 7.4 +/- 2.2; mean vibration perception threshold, 41.5 +/- 9.5 V), DPN somatic experiences (symptoms and foot ulceration), DPN psychosocial consequences (restrictions in activities of daily living [ADL] and social self-perception) and the Hospital Anxiety and Depression subscale measuring depressive symptoms (HADS-D; mean 4.9 +/- 3.7).

RESULTS

Controlling for baseline HADS-D and demographic/disease variables, NDS at baseline significantly predicted increased HADS-D over 18 months. This association was mediated by baseline unsteadiness, which was significantly associated with increased HADS-D. Baseline ADL restrictions significantly predicted increased HADS-D and partly mediated the association between baseline unsteadiness and change in HADS-D. Increased pain, unsteadiness and ADL restrictions from baseline to 9 months each significantly predicted increased HADS-D over 18 months. Change in social self-perception from baseline to 9 months significantly predicted increased HADS-D and partly mediated the relationships of change in unsteadiness and ADL restrictions with change in HADS-D.

CONCLUSIONS/INTERPRETATION

These results confirm that neuropathy is a risk factor for depressive symptoms because it generates pain and unsteadiness. Unsteadiness is the symptom with the strongest association with depression, and is linked to depressive symptoms by perceptions of diminished self-worth as a result of inability to perform social roles.

An assessment of the accuracy and usability of a novel optical wound measurement system

AIMS

Measurement of wound size can predict healing and provide information to guide treatment. This study assesses a novel optical wound imaging system that creates a three-dimensional image of the ulcer.

METHODS

Using a new camera-based digital system and traditional elliptical wound measurements, 36 foot ulcers from 31 patients (aged 44-94 years, median 70 years) were examined during a 12-week period at two centres. Median diabetes duration was 18 years (range 6-56 years). Seventeen percent had Type 1 diabetes, 93% had peripheral neuropathy and 57% had peripheral artery disease. Twenty-five were reviewed consecutively, resulting in 76 ulcer examinations. Median ulcer size was 94 mm(2), with size ranging from 3.1 to 2195 mm(2).

RESULTS

Pearson, Spearman and Kendall rank coefficients showed a strong correlation (in all cases P < 0.001) between digital measurements of wounds against traditional hand-measured estimates. Intra-observer variation of wound length using digital elliptical measurement (DEM) gave a coefficient of variation of < 3.0%. Interobserver variation of wound length using DEM was < 6.5%. Variation from a standard known-size wound area was < 8.0% across 30 trials.

CONCLUSIONS

This study shows a strong correlation between digital and traditional measurement techniques. The system can be easily deployed in routine clinical practice, providing an objective visual record, allowing remote in-depth analysis.

The Neuropad test: a visual indicator test for human diabetic neuropathy

AIMS/HYPOTHESIS

The commercially available Neuropad test was developed as a simple visual indicator test to evaluate diabetic neuropathy. It uses a colour change to define the integrity of skin sympathetic cholinergic innervation. We compared the results of Neuropad assessment in the foot with established measures of somatic and autonomic neuropathy.

METHODS

Fifty-seven diabetic patients underwent Neuropad assessment, quantitative sensory and autonomic function testing, and evaluation of intra-epidermal nerve fibre density in foot skin biopsies.

RESULTS

Neuropad responses correlated with the neuropathy disability score (r(s)=0.450, p<0.001), neuropathic symptom score (r(s)=0.288, p=0.03), cold detection threshold (r(s)=0.394, p = 0.003), heat-as-pain perception threshold visual analogue score 0.5 (r(s)=0.279, p=0.043) and deep-breathing heart rate variability (r(s)= -0.525, p<0.001). Intra-epidermal nerve fibre density (fibres/mm) compared with age- and sex-matched control subjects (11.06+/-0.82) was non-significantly reduced (7.37+/-0.93) in diabetic patients with a normal Neuropad response and significantly reduced in patients with a patchy (5.01+/-0.93) or absent (5.02+/-0.77) response (p=0.02). The sensitivity of an abnormal Neuropad response in detecting clinical neuropathy (neuropathy disability score >or=5) was 85% (negative predictive value 71%) and the specificity was 45% (positive predictive value 69%).

CONCLUSIONS/INTERPRETATION

The Neuropad test may be a simple indicator for screening patients with diabetic neuropathy.

Ethnic differences in plantar pressures in diabetic patients with peripheral neuropathy

AIMS

To compare plantar foot pressures between Caucasian and Hispanic diabetic patients with peripheral neuropathy (PN) without a history of foot ulceration and between Caucasian and Hispanic non-diabetic individuals.

METHODS

Forty-four Hispanic diabetic patients with PN (HDPN), 35 Caucasian diabetic patients with PN (CDPN), 41 non-diabetic Hispanic subjects and 33 non-diabetic Caucasian subjects participated. Total and regional peak plantar pressures (PPs) and pressure time integrals (PTIs) were assessed using the EMED-SF-4 plantar pressure system.

RESULTS

Hispanic diabetic patients with PN had significantly lower peak PP than Caucasian diabetic patients with PN in the entire foot (552.4 +/- 227.9 vs. 810.1 +/- 274.6 kPa; P < 0.001), forefoot (464.1 +/- 222.6 vs. 699.6 +/- 323.1 kPa; P < 0.001), hindfoot (296.3.4 + 101.8 vs. 398.1 + 178.3 kPa; P < 0.01) and at the fifth metatarsal head (MTH5; 204.3 +/- 143.2 vs. 388.2 +/- 273.9 kPa; P < 0.001). The PTI in the entire foot, forefoot and MTH5 were also lower in HDPN than in CDPN. The ethnic differences between the diabetic groups with PN for the entire foot, forefoot and MTH5 remained significant after adjusting for the effect of age, gender, weight and duration of diabetes. There were no significant differences in peak PP and PTI among non-diabetic individuals, except for a lower peak PP at the MTH5 in Hispanic compared with Caucasian subjects.

CONCLUSIONS

Despite a well-known higher incidence of foot complications in diabetic Hispanic subjects, dynamic plantar pressures are lower in Hispanic diabetic patients with PN when compared with their Caucasian counterparts, suggesting that differences in other risk factors exist between these two ethnic groups.

Elevated plasma CD105 and vitreous VEGF levels in diabetic retinopathy

Diabetic retinopathy is the leading cause of blindness in the industrialized world. Hyperglycaemia induces retinal hypoxia that upregulates a range of vasoactive factors which may lead to macular oedema and/or angiogenesis and hence potentially sight threatening retinopathy. In this study, we have focused on the association of CD105 and vascular endothelial growth factor (VEGF) with the development and progression of diabetic retinopathy by means of quantifying their expression in the plasma and vitreous of diabetic patients. CD105 levels were quantified in the plasma of 38 type I diabetic patients at various stages of retinopathy and 15 non-diabetic controls. In an additional cohort of 11 patients with advanced proliferative retinopathy and 23 control subjects, CD105 and VEGF were measured in the vitreous. The values were expressed as median (range) and statistical analysis was carried out using the non-parametric Mann-Whitney U test. Plasma CD105 levels were significantly increased in diabetic patients [1.8 (1.1-2.4) ng/ml] compared with non-diabetic controls [0.7 (0.3-1.8) ng/ml] (p<0.01). Plasma CD105 levels were elevated in diabetic patients with all stages of retinopathy, the highest level was observed in background retinopathy [2.3 (2.1-2.5) ng/ml] followed by proliferative retinopathy [2.1 (0.9-2.8) ng/ml] and advanced proliferative retinopathy [1.4 (0.6-1.8) ng/ml]. Vitreous contents of CD105 did not differ between controls and patients with advanced proliferative retinopathy, but vitreous levels of VEGF were elevated by approximately 3-fold in patients with advanced proliferative retinopathy [7.2 (1.90-15.60) ng/ml] compared with the control subjects [1.80 (1.10-2.210)] (p<0.01). These observations indicate that plasma levels of CD105 and vitreous levels of VEGF are associated with diabetic retinopathy, suggesting that CD105 and the angiogenic factor VEGF may play a critical role in the development and progression of diabetic retinopathy. Further studies are required to determine whether circulating CD105 levels could serve as a surrogate marker for early stage retinopathy and for monitoring disease progression.

A comparison of the monofilament with other testing modalities for foot ulcer susceptibility

We studied the number of testing sites and the proportion needed to be insensate for the optimal assessment of foot ulcer risk with the 10 g monofilament. Also, we compared the sensitivity and specificity of the 10 g monofilament with other methodologies. Fifty-two individuals with either a current foot ulcer, a history of a foot ulcer or the presence of Charcot neuroarthopathy and 51 individuals with no history of any of these conditions were assessed with the 10 g monofilament at four sites on each foot, the 128 Hz tuning fork at the halluces, the Biothesiometer at the halluces and the modified neuropathy disability score. Sensitivities and specificities were calculated for the various modalities. The Biothesiometer and the neuropathy disability score had the highest sensitivities (0.92 for both). The 128 Hz tuning fork tested only at the halluces (criterion: >or=1 insensate site) had the same sensitivity (0.86) as the 10 g monofilament tested at eight sites (criterion: >or=1 insensate site) with similar specificities (0.56 and 0.58, respectively). The Biothesiometer and the modified neuropathy disability score tend to be more sensitive than the 10 g monofilament for the assessment of individuals at risk for foot ulcers. The 128 Hz tuning fork tested at only two sites is as sensitive as the 10 g monofilament tested at eight sites. These data suggest that the 10 g monofilament may not be the optimum methodology for identifying individuals at risk of foot ulcers.

Sural nerve pathology in diabetic patients with minimal but progressive neuropathy

AIMS/HYPOTHESIS

The early pathological features of human diabetic neuropathy are not clearly defined. Therefore we quantified nerve fibre and microvascular pathology in sural nerve biopsies from diabetic patients with minimal neuropathy.

METHODS

Twelve diabetic patients underwent detailed assessment of neuropathy and fascicular sural nerve biopsy at baseline, with repeat assessment of neuropathy 8.7+/-0.6 years later.

RESULTS

At baseline, neuropathic symptoms, neurological deficits, quantitative sensory testing, cardiac autonomic function and peripheral nerve electrophysiology showed minimal abnormality, which deteriorated at follow-up. Myelinated fibre density, fibre and axonal area, and g-ratio were normal but teased fibre studies showed paranodal abnormalities (p<0.001), segmental demyelination (p<0.01) and remyelination (p<0.01) without axonal degeneration. Unassociated Schwann cell profile density (p<0.04) and unmyelinated axon density (p<0.001) were increased and axon diameter was decreased (p<0.007). Endoneurial capillaries demonstrated basement membrane thickening (p<0.006), endothelial cell hyperplasia (p<0.004) and a reduction in luminal area (p<0.007).

CONCLUSIONS/INTERPRETATION

The early pathological features of human diabetic neuropathy include an abnormality of the myelinated fibre Schwann cell and unmyelinated fibre degeneration with regeneration. These changes are accompanied by a significant endoneurial microangiopathy.

New and experimental approaches to treatment of diabetic foot ulcers: a comprehensive review of emerging treatment strategies

Diabetic foot ulcers occur in up to 15% of all diabetic patients and are a leading cause of nontraumatic amputation worldwide. Neuropathy, abnormal foot biomechanics, peripheral vascular disease and external trauma are the major contributors to the development of a foot ulcer in the diabetic patient. Therapy today includes repeated debridement, offloading, and dressings, for lower grade ulcers, and broad spectrum antibiotics and occasionally limited or complete amputation for higher grades, requiring a team effort of health care workers from various specialties. The large population affected by diabetic foot ulcers and the high rates of failure ending with amputation even with the best therapeutic regimens, have resulted in the development of new therapies and are the focus of this review. These include new off loading techniques, dressings from various materials, methods to promote wound closure using artificial skin grafts, different growth factors or wound bed modulators and methods of debridement. These new techniques are promising but still mostly unproven and traditional approaches cannot be replaced. New and generally more expensive therapies should be seen as adding to traditional approaches.

The diabetic foot: from art to science. The 18th Camillo Golgi lecture

Diabetic foot ulceration represents a major medical, social and economic problem all over the world. While more than 5% of diabetic patients have a history of foot ulceration, the cumulative lifetime incidence may be as high as 15%. Ethnic differences exist in both ulcer and amputation incidences, with both being less common in patients of Indian subcontinent origin living in the UK. Foot ulceration results from the interaction of several contributory factors, the most important of which is neuropathy. With respect to the management of acute Charcot neuroarthropathy in diabetes, recent studies suggest that bisphosphonates reduce disease activity as judged not only by differences in skin temperature, but also by assessing markers of bone turnover. The use of the total-contact cast is demonstrated in the treatment of acute Charcot feet and of plantar neuropathic ulcers. Histological evidence suggests that pressure relief results in chronic foot ulcers changing their morphological appearance by displaying some features of an acute wound. Thus, repetitive stresses on the insensate foot appear to play a major role in maintaining ulcer chronicity. It is hoped that increasing research activity in foot disease will ultimately result in fewer ulcers and less amputation in diabetes.

Electrical stimulation therapy through stocking electrodes for painful diabetic neuropathy: a double blind, controlled crossover study

AIMS

Peripheral neuropathy affects more than a third of diabetic patients, of whom a significant minority will have disabling symptoms. The aim of this study was to assess the efficacy of pulsed-dose electrical stimulation (through stocking electrodes) in the treatment of painful diabetic neuropathy.

METHODS

Thirty patients with painful diabetic neuropathy were consecutively randomised to wear silver-plated nylon-dacron stocking electrodes for 8 h a night for 6 weeks (pulsed electric current of 50 micro amps delivered by a microcomputer). The control, identical stockings received an insignificant current (5 micro amps). Pre-treatment, weekly and end-of-treatment pain and sleep disturbance scores were recorded.

RESULTS

Fourteen patients completed the study (the 16 non-completers withdrew during the first phase). Mean (+/- sd) age: 57.5 +/- 10.5 years; HbA(1c): 8.3 +/- 1.4%; median (IQR) duration of diabetes: 14.5 (7.6-19.3) years; duration of neuropathy: 4 (3-7) years. Active treatment and control produced similar reductions in pain scores [median (IQR): 40.1 (4.7-97.7)% vs. 49.2 (0.2-91.1)%, P = 0.70] and sleep disturbance scores [median (IQR): 31.1 (-4.6 to 85.4)% vs. 42.6 (-16.2 to 91.1)%, P = 0.70]. Non-completers (seven on active treatment, nine on control) withdrew for similar reasons (inconvenience, exacerbation of symptoms, dermatitis).

CONCLUSIONS

There is no evidence from these results that this treatment is more effective than control in the treatment of painful diabetic neuropathy.

Corneal confocal microscopy: a non-invasive surrogate of nerve fibre damage and repair in diabetic patients

AIMS/HYPOTHESIS

The accurate detection, characterization and quantification of human diabetic neuropathy are important to define at risk patients, anticipate deterioration, and assess new therapies. Corneal confocal microscopy is a reiterative, rapid, non-invasive in vivo clinical examination technique capable of imaging corneal nerve fibres. The aim of this study was to define the ability of this technique to quantify the extent of degeneration and regeneration of corneal nerve fibres in diabetic patients with increasing neuropathic severity.

METHODS

We scanned the cornea and collected images of Bowman's layer (containing a rich nerve plexus) from 18 diabetic patients and 18 age-matched control subjects.

RESULTS

Corneal nerve fibre density (F(3)=9.6, p<0.0001), length (F(3)=23.8, p<0.0001), and branch density (F(3)=13.9, p<0.0001) were reduced in diabetic patients compared with control subjects, with a tendency for greater reduction in these measures with increasing severity of neuropathy.

CONCLUSION/INTERPRETATION

Corneal confocal microscopy is a rapid, non-invasive in vivo clinical examination technique which accurately defines the extent of corneal nerve damage and repair and acts as a surrogate measure of somatic neuropathy in diabetic patients. It could represent an advance to define the severity of neuropathy and expedite assessment of therapeutic efficacy in clinical trials of human diabetic neuropathy.

Methicillin-resistant Staphylococcus aureus in the diabetic foot clinic: a worsening problem

AIMS

To determine if there has been a change in the prevalence of pathogenic organisms in foot ulcers in diabetic patients in 2001 compared with our previous study in 1998.

METHODS

A retrospective analysis of wound swabs taken from infected foot ulcers in diabetic patients attending the outpatient clinic in the Manchester Foot Hospital over a twelve-month period. A total of 63 patients with positive wound swabs were identified.

RESULTS

Gram-positive aerobic bacteria still predominate (84.2%) and the commonest single isolate remains Staphylococcus aureus (79.0%) which is higher than we previously reported. MRSA was isolated in 30.2% of the patients which is almost double the proportion of MRSA-affected patients three years ago. This did not appear to be related to prior antibiotic usage. There was no increase in hospitalisation because of MRSA infection.

CONCLUSIONS

The problem of MRSA continues to increase despite the precautions taken to prevent MRSA spread. There is a need for a multi-centre study looking into the prevalence of MRSA in diabetic foot ulcer and how this can be reduced in the diabetic foot clinic.

The relationship between blood glucose excursions and painful diabetic peripheral neuropathy: a pilot study

AIMS

Peripheral neuropathy affects 30% of Type 1 diabetic patients. Unfortunately, 10-20% of affected patients have disabling symptoms. The aim of this study was to examine the relationship between blood glucose excursions and pain in patients with symptomatic diabetic neuropathy.

METHODS

Twenty Type 1 diabetic patients with peripheral neuropathy (10 painful and 10 painless) wore a continuous glucose monitoring system for 3 days. Symptomatic patients kept a daily pain score diary. The mean amplitude of glycaemic excursions (MAGE) and the M-values (measure of glucose deviations from an arbitrarily selected point) were calculated.

RESULTS

Groups were matched for (mean +/- sd) age: 52.0 +/- 11.1 years; duration of diabetes: 24.8 +/- 10.7 years; HbA1c: 9.7 +/- 2.3%; duration of neuropathy: 5.6 +/- 2.6 years; and CGMS performance. The painful group had a greater mean glucose (12.1 +/- 2.9 mmol/l vs. 9.3 +/- 1.9 mmol/l, P = 0.02), a greater M-value (68.4 vs. 31.1, P = 0.02) and more glycaemic excursions (13 vs. 10, P < 0.01), compared with the painless group. However, there was no difference in the MAGE between both groups, and no correlation between the number of glycaemic excursions and the number of painful episodes in the painful group.

CONCLUSIONS

Patients with painful neuropathy have greater glucose flux and possibly poorer diabetes control, compared with patients with painless neuropathy.

Blood glucose overestimation in diabetic patients on continuous ambulatory peritoneal dialysis for end-stage renal disease

AIMS

Diabetic patients on continuous ambulatory peritoneal dialysis (CAPD) for renal failure depend on glucose analysers for regular monitoring of glycaemic control. We aim to inform health professionals of the potentially dangerous overestimation of blood glucose values by some analysers in patients using Icodextrin for dialysis.

METHODS

Twenty-five patients on continuous ambulatory peritoneal dialysis (10 patients on an 8-12-h nocturnal exchange of Icodextrin) had random glucose analysis performed on venous blood using standardized reference laboratory (lab) technique (glucose oxidase GOD-PAP), and simultaneously on capillary blood using the Precision Q.I.D System (glucose oxidase method) and the Advantage meter (glucose dehydrogenase method).

RESULTS

The Precision Q.I.D System agreed with the lab results in both the Icodextrin group and the non-Icodextrin group (80-90% of values fell within 20% of the corresponding lab result). In contrast, the Advantage meter agreed with the lab results only in the non-Icodextrin group (95% of values within 20% of the corresponding lab value), and not in the Icodextrin group, where only 5% of the analyser values fell within 20% of the corresponding lab value.

CONCLUSIONS

The Precision Q.I.D System, which utilizes glucose oxidase reaction, is safe for use in diabetic patients treated with Icodextrin. All analysers must be cross-checked with the laboratory reference method before use in these patients.

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.

Natural history and prognostic factors of diabetic nephropathy in type 2 diabetes

BACKGROUND

The causes and mechanisms of increased mortality of patients with diabetic nephropathy are unclear, and its natural history is poorly understood.

AIM

To evaluate risk factors for mortality in type 2 diabetic patients with nephropathy.

DESIGN

Retrospective study of clinical and biochemical parameters in diabetic nephropathic patients and controls sampled from a secondary care register.

METHODS

We studied 170 type 2 diabetic patients (from 1987 to 1995) with nephropathy (proteinuria >0.5 g/24 h) and 170 non-nephropathic patients. Follow-up was until death or December 1997. Details of demographics, clinical and treatment history were obtained from medical records.

RESULTS

Mean follow-up was 5.3 years. Of the patients with nephropathy at baseline, 63 (37%) died compared with 14 (8%) non-nephropathic patients (chi(2)=53.8, p<0.0001). Age- and sex-adjusted all-cause mortality rates were 8.1 (6.4, 9.8) and 1.4 (0.5, 2.2) deaths per 100 person-years, respectively (rate ratio 5.8). Forty-four patients (57%) died from cardiovascular causes (rate ratio 5.4). Mortality was directly proportional to degree of proteinuria: 0.5-2 g/24 h, 4.6 (2.9-7.1); >2 g/24 h, 9.9 (7.3-13.5) per 100 patient-years. A 36% (5-78%) excess risk of mortality was observed for each log unit increase in proteinuria. Multivariate Cox regression analyses confirmed a five-fold excess risk for all-cause and cardiovascular mortality in patients with nephropathy compared with those without. This was independent of other risk factors including baseline age [5% (1-8%)/year], creatinine [2.5 (1.12-5.6)/10 micromol/l] and glycaemic control (HbA(1c)) [15% (1-31%) per 1% rise].

CONCLUSIONS

Proteinuria is a potentially preventable and reversible risk factor associated with high mortality in type 2 diabetic patients. Prevention of the development of overt nephropathy and improvement in diabetes control may reduce mortality in these patients.