The co-existence of peripheral and vestibular neuropathy in diabetes: a cross-sectional study

PURPOSE

Diabetic neuropathy can lead to decreased peripheral sensation and motor neuron dysfunction associated with impaired postural control and risk of falling. However, the relationship between decreased peripheral sensation and impaired vestibular function in diabetes mellitus is poorly investigated. Therefore, the aim of this study was to investigate the relationship between peripheral and autonomic measurements of diabetic neuropathy and measurements of vestibular function.

METHODS

A total of 114 participants with type 1 diabetes (n = 52), type 2 diabetes (n = 51) and controls (n = 11) were included. Vestibular function was evaluated by video head impulse testing. Peripheral neuropathy was assessed by quantitative sensory testing and nerve conduction. Autonomic neuropathy using the COMPASS 31 questionnaire. Data were analyzed according to data type and distribution.

RESULTS

Measurements of vestibular function did not differ between participants with type 1 diabetes, type 2 diabetes or controls (all p-values above 0.05). Subgrouping of participants according to the involvement of large-, small- or autonomic nerves did not change this outcome. Correlation analyses showed a significant difference between COMPASS 31 and right lateral gain value (ρ = 0.23, p = 0.02,), while no other significant correlations were found.

CONCLUSION

Diabetic neuropathy does not appear to impair vestibular function in diabetes, by means of the VOR.

CLINICAL TRIALS

NCT05389566, May 25th, 2022.

Painful Diabetic Neuropathy: The Need for New Approaches

Painful diabetic neuropathy is a common vexing problem for people with diabetes and a costly problem for society. The pathophysiology is not well understood, and no safe and effective mechanistically-based treatment has been identified. Poor glycemic control is a risk factor for painful diabetic neuropathy. Excessive intraneuronal glucose in people with diabetes can be shunted away from physiological glycolysis into multiple pathological pathways associated with neuropathy and pain. The first three treatments that are traditionally offered consist of risk factor reduction, lifestyle modifications, and pharmacological therapy, which includes only three drugs that are approved for this indication by the United States Food and Drug Administration. All of these traditional treatments are often inadequate for relieving neuropathic pain, and thus, new approaches are needed. Modern devices based on neuromodulation technology, which act directly on the nervous system, have been recently cleared by the United States Food and Drug Administration for painful diabetic neuropathy and offer promise as next-in-line therapy when traditional therapies fail.

Spinal Cord Stimulation for Painful Diabetic Neuropathy

Spinal cord stimulation (SCS) technology has been recently approved by the US Food and Drug Administration (FDA) for painful diabetic neuropathy (PDN). The treatment involves surgical implantation of electrodes and a power source that delivers electrical current to the spinal cord. This treatment decreases the perception of pain in many chronic pain conditions, such as PDN. The number of patients with PDN treated with SCS and the amount of data describing their outcomes is expected to increase given four factors: (1) the large number of patients with this diagnosis, (2) the poor results that have been obtained for pain relief with pharmacotherapy and noninvasive non-pharmacotherapy, (3) the results to date with investigational SCS technology, and (4) the recent FDA approval of systems that deliver this treatment. Whereas traditional SCS replaces pain with paresthesias, a new form of SCS, called high-frequency 10-kHz SCS, first used for pain in 2015, can relieve PDN pain without causing paresthesias, although not all patients experience pain relief by SCS. This article describes (1) an overview of SCS technology, (2) the use of SCS for diseases other than diabetes, (3) the use of SCS for PDN, (4) a comparison of high-frequency 10-kHz and traditional SCS for PDN, (5) other SCS technology for PDN, (6) deployment of SCS systems, (7) barriers to the use of SCS for PDN, (8) risks of SCS technology, (9) current recommendations for using SCS for PDN, and (10) future developments in SCS.

Rectal sensitivity correlated with gastrointestinal-mediated glucose disposal, but not the incretin effect

OBJECTIVE

The mechanisms behind the diminished incretin effect in type 2 diabetes are uncertain, but impaired vagal transmission has been suggested. We aimed to investigate the association between the incretin effect and autonomic neuropathy, and the degree of dysglycaemia and duration of diabetes.

DESIGN AND METHODS

For a cross-sectional study, we included participants with either longstanding type 2 diabetes, recent onset, untreated diabetes and controls without diabetes matched for age, sex and body mass index. Autonomic nerve function was assessed with cardiovascular reflex tests, heart rate variability and sudomotor function. Visceral afferent nerves in the gut were tested performing rapid rectal balloon distention. An oral glucose tolerance test and an intravenous isoglycaemic glucose infusion were performed to calculate the incretin effect and gastrointestinal-mediated glucose disposal (GIGD).

RESULTS

Sixty-five participants were recruited. Participants with diabetes had rectal hyposensitivity for earliest sensation (3.7 ± 1.1 kPa in longstanding, 4.0 ± 1.3 in early), compared to controls (3.0 ± 0.9 kPa), p = .005. Rectal hyposensitivity for earliest sensation was not associated with the incretin effect (rho = -0.204, p = .106), but an association was found with GIGD (rho -0.341, p = .005). Incretin effect and GIGD were correlated with all glucose values, HbA1c and duration of diabetes.

CONCLUSIONS

Rectal hyposensitivity was uncovered in both longstanding and early type 2 diabetes, and was not associated with the incretin effect, but with GIGD, implying a potential link between visceral neuropathy and gastrointestinal handling of glucose. Both the incretin effect and GIGD were associated with the degree of dysglycaemia and the duration of diabetes.

PREVIOUSLY PUBLISHED

Some of the data have previously been published and presented as a poster on the American Diabetes Association 83rd Scientific Sessions: Meling et al; 1658-P: Rectal Hyposensitivity, a Potential Marker of Enteric Autonomic Nerve Dysfunction, Is Significantly Associated with Gastrointestinally Mediated Glucose Disposal in Persons with Type 2 Diabetes. Diabetes 20 June 2023; 72 (Supplement_1): 1658-P. https://doi.org/10.2337/db23-1658-P.

The stability of perception threshold tracking for long session evaluation of Aβ- and Aδ-fiber function

INTRODUCTION/AIMS

Research has proven that epidermal and transcutaneous stimulation can identify the function of Aβ and Aδ fibers (i.e., in diabetes) individually using different electrodes. In this study we aimed to determine the stability of perception thresholds when using such electrodes.

METHODS

Twenty healthy volunteers participated in this study. The perception threshold of Aβ fibers (patch electrode) and Aδ fibers (pin electrode) was estimated 30 times during a period of 60 minutes. A threshold was established every other minute, alternating between the two electrodes. The stimulus duration was 1 millisecond and the interstimulus interval was 1.5 to 2.5 seconds. Linear regressions of the perception threshold as a function of time were performed. The slopes were used as an estimate of habituation and were compared between the electrodes.

RESULTS

The slope was significantly larger when assessed by the pin electrode (median: 0.020 [0.009 to 0.030] mA/trial) than when assessed by the patch electrode (median: 0.005 [0.001 to 0.018] mA/trial) (P = .017, paired t test). During the session, total increases in perception threshold of approximately 55% and 1% were seen for the pin and patch electrodes, respectively.

DISCUSSION

The two fiber types assessed showed significant perception threshold increases. The higher slope of the pin electrode indicated that the Aδ fibers were more prone to habituation than the Aβ fibers, and that habituation should be considered during prolonged experiments. This assessment is valuable for future research on nerve fiber function using the technique for long session experiments.

A Glycemia Risk Index (GRI) of Hypoglycemia and Hyperglycemia for Continuous Glucose Monitoring Validated by Clinician Ratings

BACKGROUND

A composite metric for the quality of glycemia from continuous glucose monitor (CGM) tracings could be useful for assisting with basic clinical interpretation of CGM data.

METHODS

We assembled a data set of 14-day CGM tracings from 225 insulin-treated adults with diabetes. Using a balanced incomplete block design, 330 clinicians who were highly experienced with CGM analysis and interpretation ranked the CGM tracings from best to worst quality of glycemia. We used principal component analysis and multiple regressions to develop a model to predict the clinician ranking based on seven standard metrics in an Ambulatory Glucose Profile: very low-glucose and low-glucose hypoglycemia; very high-glucose and high-glucose hyperglycemia; time in range; mean glucose; and coefficient of variation.

RESULTS

The analysis showed that clinician rankings depend on two components, one related to hypoglycemia that gives more weight to very low-glucose than to low-glucose and the other related to hyperglycemia that likewise gives greater weight to very high-glucose than to high-glucose. These two components should be calculated and displayed separately, but they can also be combined into a single Glycemia Risk Index (GRI) that corresponds closely to the clinician rankings of the overall quality of glycemia (r = 0.95). The GRI can be displayed graphically on a GRI Grid with the hypoglycemia component on the horizontal axis and the hyperglycemia component on the vertical axis. Diagonal lines divide the graph into five zones (quintiles) corresponding to the best (0th to 20th percentile) to worst (81st to 100th percentile) overall quality of glycemia. The GRI Grid enables users to track sequential changes within an individual over time and compare groups of individuals.

CONCLUSION

The GRI is a single-number summary of the quality of glycemia. Its hypoglycemia and hyperglycemia components provide actionable scores and a graphical display (the GRI Grid) that can be used by clinicians and researchers to determine the glycemic effects of prescribed and investigational treatments.

Optimizing examination time and diagnostic performance of the histamine-induced axon-reflex flare response in diabetes

INTRODUCTION/AIMS

The axon-reflex flare response is a reliable method for functional assessment of small fibers in diabetic peripheral neuropathy (DPN), but broad adoption is limited by the time requirement. The aims of this study were to (1) assess diagnostic performance and optimize time required for assessing the histamine-induced flare response and (2) associate with established parameters.

METHODS

A total of 60 participants with type 1 diabetes with (n = 33) or without (n = 27) DPN participated. The participants underwent quantitative sensory testing (QST), corneal confocal microscopy (CCM), and flare intensity and area size assessments by laser-Doppler imaging (FLPI) following an epidermal skin-prick application of histamine. The flare parameters were evaluated each minute for 15 min, and the diagnostic performance compared to QST and CCM were assessed using area under the curve (AUC). Minimum time-requirements until differentiation and to achieve results comparable with a full examination were assessed.

RESULTS

Flare area size had better diagnostic performance compared with CCM (AUC 0.88 vs. 0.77, p < 0.01) and QST (AUC 0.91 vs. 0.81, p = 0.02) than mean flare intensity, and could distinguish people with and without DPN after 4 min compared to after 6 min (both p < 0.01). Flare area size achieved a diagnostic performance comparable to a full examination after 6 and 7 min (CCM and QST respectively, p > 0.05), while mean flare intensity achieved it after 5 and 8 min (CCM and QST respectively, p > 0.05).

DISCUSSION

The flare area size can be evaluated 6-7 min after histamine-application, which increases diagnostic performance compared to mean flare intensity.

The Composite Autonomic Symptom Score 31 Questionnaire: A Sensitive Test to Detect Risk for Autonomic Neuropathy

Background and Aims

Autonomic neuropathy is a common but often neglected complication of diabetes, prediabetes, and even in individuals with an elevated risk of diabetes. The Composite Autonomic Symptom Score (COMPASS) 31 is a validated and easy-to-use questionnaire regarding autonomic symptoms. We aimed to use a digitally, Norwegian version of the COMPASS 31 in people with different durations of diabetes and healthy controls to consider feasibility and to investigate if scores could discriminate between positive and negative outcomes for established tests for diabetic neuropathy, including cardiovascular autonomic neuropathy (CAN) and a novel method of examining the gastrointestinal visceral sensitivity.

Method

We included 21 participants with longstanding type 2 diabetes, 15 with early type 2 diabetes, and 30 matched controls. The mean age for all groups was 69 years. Participants were phenotyped by cardiovascular autonomic reflex tests, electrical skin conductance, sural nerve electrophysiology, and the monofilament test. As a proxy for gastrointestinal visceral and autonomic nerve function, evoked potentials were measured following rapid rectal balloon distention.

Results

Participants with longstanding diabetes scored a median (IQR) of 14.9 (10.8-28.7) points, early diabetes of 7.3 (1.6-15.2), and matched controls of 8.6 (4.1-21.6), p = 0.04. Women and men scored 14.4 (5.5-28.7) and 7.8 (3.6-14.6) points, respectively, p = 0.01. Participants with definite or borderline CAN scored 14.3 (10.4-31.9) points, compared to participants with no CAN, 8.3 (3.2-21.5), p = 0.04. Lowering the diagnostic cut-off from 16 to 10 points increased the sensitivity from 0.33 to 0.83, with a decreased specificity from 0.68 to 0.55.

Conclusion

We successfully used COMPASS 31 in Norwegian. Thus, following the guidelines, we suggest clinical implementation for the assessment of autonomic neuropathy. Participants with longstanding diabetes had an increased likelihood of symptoms and signs of autonomic neuropathy. For screening purposes, the sensitivity was improved by lowering the cut-off to 10 points, with a lower score nearly excluding the diagnosis.

The PanGut-study: Evoked potentials following rectal balloon distention, a way of evaluating diabetic autonomic neuropathy in the gut?

AIM

There is a lack of methods for investigating the autonomic nerves of the gastrointestinal tract. Our aim was to explore a novel test measuring visceral sensory evoked potentials (EPs) in response to rapid balloon distention in the rectum and compare it to established tests for diabetic neuropathy.

METHOD

Participants with longstanding type 2 diabetes, newly onset, untreated diabetes <1 year, and matched controls, were included. Tests included cardiovascular reflex tests, orthostatic blood pressure, electrical skin conductance assessment, sural nerve testing and monofilament test. The rectal balloon distention pressure at earliest sensation and threshold of unpleasantness were identified and used to elicit mechanical EPs.

RESULTS

The pressure at earliest sensation was higher in people with diabetes, 0.038 (0.012) bar vs. controls 0.030 (0.009) bar, p = 0.002, and in people with signs of peripheral neuropathy, 0.045 (0.014) bar, p < 0.01. Clinical correlations between EP amplitude and latency, and other tests were found.

CONCLUSIONS

Rectal hyposensitivity was associated with both longstanding and early diabetes, indicating enteric sensory dysfunction already in early stages of diabetes. Correlation analyses may indicate that central afferent processing is affected in parallel with peripheral neuronal function.

Cognitive function in individuals with and without painful and painless diabetic polyneuropathy-A cross-sectional study in type 1 diabetes

INTRODUCTION

Previous studies suggest that cognitive impairment is more prevalent in individuals with painful and painless diabetic peripheral neuropathy (DPN). However, the current evidence is not well described. This study investigated cognitive function in adults with type 1 diabetes mellitus (T1DM) and the association to painful/painless DPN and clinical parameters.

METHODS

This cross-sectional, observational, case-control study included 58 participants with T1DM, sub-grouped into 20 participants with T1DM and painful DPN, 19 participants with T1DM and painless DPN, 19 participants with T1DM without DPN, and 20 healthy controls were included. The groups were matched for sex and age. The participants performed Addenbrooke's examination III (ACE-III), which assesses attention, memory, verbal fluency, language and visuospatial skills. Working memory was evaluated using an N-back task. Cognitive scores were compared between the groups and correlated to age, diabetes duration, HbA1c and nerve conduction measurements.

RESULTS

Compared to healthy controls, T1DM participants showed lower total ACE-III (p = .028), memory (p = .013) and language scores (p = .028), together with longer reaction times in the N-back task (p = .041). Subgroup analyses demonstrated lower memory scores in those with painless DPN compared with healthy controls (p = .013). No differences were observed between the three T1DM subgroups. Cognitive scores and clinical parameters were not associated.

CONCLUSIONS

This study supports the notion of cognitive alterations in T1DM and indicates that cognitive function is altered in T1DM regardless of underlying neuropathic complications. The memory domain appears altered in T1DM, particularly in those with painless DPN. Further studies are needed to verify the findings.

Perception threshold tracking: validating a novel method for assessing function of large and small sensory nerve fibers in diabetic peripheral neuropathy with and without pain

ABSTRACT

It remains unknown why some people with diabetes develop painful neuropathies while others experience no pain. This study aimed to validate a novel method for assessing the function of small sensory nerves in diabetes to further elucidate this phenomenon. The function of large and small nerves was assessed using a novel perception threshold tracking technique in 3 well-characterized groups (n = 60) with type 1 diabetes, namely, (1) painful diabetic peripheral neuropathy (T1DM + PDPN), (2) painless diabetic peripheral neuropathy (T1DM + DPN), and (3) no neuropathy (T1DM - DPN), and healthy controls (n = 20). Electrical currents with different shapes, duration, and intensities were applied by 2 different skin electrodes activating large and small fibers, respectively. The minimal current needed to activate the fibers were analyzed as the rheobase of the stimulus-response function. Nerve fiber selectivity was measured by accommodation properties of stimulated nerves. The rheobase of both fiber types were highest for T1DM + PDPN, followed by T1DM + DPN, T1DM - DPN, and healthy controls, indicating that the nerve properties are specific in individuals with diabetes and pain. There was an overall significant difference between the groups ( P < 0.01). The accommodation properties of stimulated fibers were different between the 2 electrodes ( P < 0.05) apart from in the group with T1DM + PDPN, where both electrodes stimulated nerves displaying properties similar to large fibers. Perception threshold tracking reveals differences in large and small nerve fiber function between the groups with and without diabetes, DPN, and pain. This indicates that the methods have potential applications in screening DPN and explore further the features differentiating painful from nonpainful DPN.

The co-existence of sensory and autonomic neuropathy in type 1 diabetes with and without pain

AIMS

To investigate the co-existence of diabetic peripheral neuropathy (DPN), painful diabetic peripheral neuropathy (PDPN), and cardiac autonomic neuropathy (CAN) and to establish a model to predict CAN based on peripheral measurements.

METHODS

Eighty participants (20 type 1 diabetes (T1DM) + PDPN, 20 T1DM + DPN, 20 T1DM-DPN (without DPN), and 20 healthy controls (HC)) underwent quantitative sensory testing, cardiac autonomic reflex tests (CARTs), and conventional nerve conduction. CAN was defined as ≥ 2 abnormal CARTs. After the initial analysis, the participants with diabetes were re-grouped based on the presence or absence of small (SFN) and large fibre neuropathy (LFN), respectively. A prediction model for CAN was made using logistic regression with backward elimination.

RESULTS

CAN was most prevalent in T1DM + PDPN (50%), followed by T1DM + DPN (25%) and T1DM-DPN and HC (0%). The differences in prevalence of CAN between T1DM + PDPN and T1DM-DPN/HC were significant (p < 0.001). When re-grouping, 58% had CAN in the SFN group and 55% in the LFN group, while no participants without either SFN or LFN had CAN. The prediction model had a sensitivity of 64%, a specificity of 67%, a positive predictive value of 30%, and a negative predictive value of 90%.

CONCLUSION

This study suggests that CAN predominantly co-exists with concomitant DPN.

Diagnostic Accuracy of Perception Threshold Tracking in the Detection of Small Fiber Damage in Type 1 Diabetes

AIM

An objective assessment of small nerve fibers is key to the early detection of diabetic peripheral neuropathy (DPN). This study investigates the diagnostic accuracy of a novel perception threshold tracking technique in detecting small nerve fiber damage.

METHODS

Participants with type 1 diabetes (T1DM) without DPN (n = 20), with DPN (n = 20), with painful DPN (n = 20) and 20 healthy controls (HCs) underwent perception threshold tracking on the foot and corneal confocal microscopy. Diagnostic accuracy of perception threshold tracking compared to corneal confocal microscopy was analyzed using logistic regression.

RESULTS

The rheobase, corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and corneal nerve fiber length (CNFL) (all P < .001) differed between groups. The diagnostic accuracy of perception threshold tracking (rheobase) was excellent for identifying small nerve fiber damage, especially for CNFL with a sensitivity of 94%, specificity 94%, positive predictive value 97%, and negative predictive value 89%. There was a significant correlation between rheobase with CNFD, CNBD, CNFL, and Michigan Neuropathy Screening Instrument (all P < .001).

CONCLUSION

Perception threshold tracking had a very high diagnostic agreement with corneal confocal microscopy for detecting small nerve fiber loss and may have clinical utility for assessing small nerve fiber damage and hence early DPN.

CLINICAL TRIALS

NCT04078516.

Alterations in Functional Connectivity of Thalamus and Primary Somatosensory Cortex in Painful and Painless Diabetic Peripheral Neuropathy

OBJECTIVE

In this study we aimed to investigate the functional connectivity of brain regions involved in sensory processing in diabetes with and without painful and painless diabetic peripheral neuropathy (DPN) and the association with peripheral nerve function and pain intensity.

RESEARCH DESIGN AND METHODS

In this cross-sectional study we used resting-state functional MRI (fMRI) to investigate functional brain connectivity of 19 individuals with type 1 diabetes and painful DPN, 19 with type 1 diabetes and painless DPN, 18 with type 1 diabetes without DPN, and 20 healthy control subjects. Seed-based connectivity analyses were performed for thalamus, postcentral gyrus, and insula, and the connectivity z scores were correlated with peripheral nerve function measurements and pain scores.

RESULTS

Overall, compared with those with painful DPN and healthy control subjects, subjects with type 1 diabetes without DPN showed hyperconnectivity between thalamus and motor areas and between postcentral gyrus and motor areas (all P ≤ 0.029). Poorer peripheral nerve functions and higher pain scores were associated with lower connectivity of the thalamus and postcentral gyrus (all P ≤ 0.043). No connectivity differences were found in insula (all P ≥ 0.071).

CONCLUSIONS

Higher functional connectivity of thalamus and postcentral gyrus appeared only in diabetes without neuropathic complications. Thalamic/postcentral gyral connectivity measures demonstrated an association with peripheral nerve functions. Based on thalamic connectivity, it was possible to group the phenotypes of type 1 diabetes with painful/painless DPN and type 1 diabetes without DPN. The results of the current study support that fMRI can be used for phenotyping, and with validation, it may contribute to early detection and prevention of neuropathic complications.

The Histamine-Induced Axon-Reflex Response in People With Type 1 Diabetes With and Without Peripheral Neuropathy and Pain: A Clinical, Observational Study

Small nerve fibres are important when studying diabetic peripheral neuropathy (DPN) as they could be first affected. However, assessing their integrity and function adequately remains a major challenge. The aim of this study was to investigate the association between different degrees of DPN, the presence of neuropathic pain, and the intensity of the axon-reflex flare response provoked by epidermal histamine. Eighty adults were included and divided into 4 groups of 20 with type 1 diabetes and: painful DPN (T1DM+PDPN), non-painful DPN (T1DM+DPN), no DPN and no pain (T1DM-DPN), and 20 persons without diabetes or pain (HC). The vasomotor responses were captured by a Full-field Laser Speckle Perfusion Imager. The response was lowest in T1DM+DPN, followed by T1DM+PDPN, T1DM-DPN and HC. The response was significantly reduced in DPN (T1DM+DPN, T1DM+PDPN) compared with people without (T1DM-DPN, HC) (P < .001). The response was also attenuated in diabetes irrespective of the degree of DPN (T1DM+PDPN, T1DM+DPN, T1DM-DPN) (P < .001). There were no differences in the response between painful neuropathy (T1DM+PDPN) and painless DPN (T1DM+DPN) (P = .189). The method can distinguish between groups with and without diabetes and with and without DPN but cannot distinguish between groups with and without painful DPN. PERSPECTIVE: This study describes how diabetes attenuates the axon-reflex response, and how it is affected by neuropathy and pain clarifying previous findings. Furthermore, the study is the first to utilize histamine when evoking the response, thus providing a new and fast alternative for future studies into the pathophysiology of neuropathic pain.

Gray Matter Brain Alterations in Type 1 Diabetes - Findings Based on Detailed Phenotyping of Neuropathy Status

AIMS

This study investigated brain structure in patients of type 1 diabetes with diabetic peripheral neuropathy (DPN) and type 1 diabetes with neuropathic pain and the associations to clinical, peripheral, and cognitive measurements.

METHODS

Sixty individuals with type 1 diabetes and 20 healthy controls were included in the study. Nineteen individuals with type 1 diabetes and neuropathic pain, 19 with type 1 diabetes and DPN, 18 with type 1 diabetes without DPN, and 20 healthy controls were included in the brain analyses. We utilized structural brain magnetic resonance imaging to investigate total and regional gray matter volume.

RESULTS

Significant lower gray matter volume was found in type 1 diabetes with neuropathic pain and in type 1 diabetes without DPN compared to healthy controls (p=0.024 and p=0.019, respectively). Lower insula volume was observed in all three diabetes groups (all p≤0.050). Thalamus and hippocampus volume was lower in type 1 diabetes with neuropathic pain, cerebellum volume was lower in type 1 diabetes with DPN, and somatosensory cortex volume was lower in type 1 diabetes without DPN (all p≤0.018). Attenuated memory was associated with lower gray matter volume in type 1 diabetes with DPN. No associations were found between gray matter volume and clinical/peripheral measurements.

CONCLUSION

We demonstrated lower gray matter volume in individuals with type 1 diabetes regardless of the presence of DPN and neuropathic pain. Hence, central gray matter alteration was not associated with peripheral alterations.

Incidence, hospitalization and mortality and their changes over time in people with a first ever diabetic foot ulcer

AIMS

A diabetic foot ulcer (DFU) is a severe condition associated with morbidity and mortality. Population-based studies are rare and limited by access to reliable data. Without this data, efforts in primary prevention cannot be evaluated. Therefore, we examined the incidence and changes over time for the first DFU in people with diabetes. We also examined hospitalization and all-cause mortality and their changes over time.

METHODS

From the UK primary care CPRD GOLD database (2007-2017), we identified 129,624 people with diabetes by a prescription for insulin or a non-insulin anti-diabetic drug. DFUs were identified using Read codes and expressed as incidence rates (IRs). Changes over time were described using Poisson and logistic regression and expressed as incidence rate ratios (IRRs) and odds ratios (ORs) respectively.

RESULTS

The mean IR of first registered DFUs was 2.5 [95% CI: 2.1-2.9] per 1000 person-years for people with type 2 diabetes and 1.6 [1.3-1.9] per 1000 person-years for people with type 1. The IRs declined for people with type 2 diabetes (IRR per year: 0.97 [0.96-0.99]), while no changes were observed for people with type 1 diabetes (IRR per year: 0.96 [0.89-1.04]). Average hospitalization and 1-year mortality risk for people with type 2 diabetes were 8.2% [SD: 4.7] and 11.7% [SD: 2.2] respectively. Both declined over time (OR: 0.89 [0.84, 0.94] and 0.94 [0.89, 0.99]).

CONCLUSION

The decline in all IRs, hospitalizations and mortality in people with type 2 diabetes suggests that prevention and care of the first DFU has improved for this group in primary care in the UK.

Gastrointestinal function in diabetes is affected regardless of asymptomatic appearance

BACKGROUND

Gastrointestinal dysmotility may exist without concomitant symptoms. We hypothesize that asymptomatic individuals with diabetes have altered gastrointestinal function associated with age, cardiac vagal tone and glycaemic control.

METHODS

One hundred fifty-four asymptomatic participants (61 with type 1 diabetes (T1D), 70 type 2 diabetes (T2D) and 23 healthy volunteers (HV)) underwent wireless motility capsule investigation. Transit times, motility indices and pH were retrieved. Age, cardiac vagal tone, glucose and haemoglobin A1c levels were collected.

RESULTS

In T1D, prolongation of colonic (p = 0.03) and whole-gut transit times (p = 0.04) were shown. Transpyloric pH rise was decreased in T1D (p = 0.001) and T2D (p = 0.007) and was associated with cardiac vagal tone (p = 0.03) or glucose (p = 0.04) and haemoglobin A1c (p = 0.005). Ileocaecal pH fall was decreased in T2D (p < 0.001).

CONCLUSIONS

Gastrointestinal function was altered in asymptomatic individuals with diabetes. These findings call for further investigations of gastrointestinal function in order to identify risk factors or even predictors for diabetic enteropathy, particularly when glycaemic control is impaired.

The Cost-Effectiveness of Subcutaneous Semaglutide Versus Empagliflozin in Type 2 Diabetes Uncontrolled on Metformin Alone in Denmark

INTRODUCTION

International and Danish guidelines recommend the use of glucagon-like peptide 1 receptor agonists (GLP-1 RA) and sodium-glucose cotransporter 2 (SGLT-2) inhibitors already in second line in the management of type 2 diabetes (T2D). The objective of this study was to evaluate the long-term cost-effectiveness (CE) of subcutaneous (SC) semaglutide (GLP-1 RA) versus empagliflozin (SGLT-2 inhibitor) in individuals with T2D uncontrolled on metformin alone from a Danish payer's perspective.

METHODS

Cost-effectiveness analyses (CEA) were conducted from a Danish payer's perspective, using the IQVIA Core Diabetes model (CDM 9.5), with a time horizon of 50 years and an annual discount of 4% on costs and effects. Patients received either SC semaglutide or empagliflozin, in addition to metformin, until HbA1c threshold of 7.5% (58 mmol/mol) was reached, following which treatment intensification with insulin glargine in addition to empagliflozin or SC semaglutide plus metformin was considered. Baseline cohort characteristics and treatment effects were sourced from a published CEA. Utilities and cost of diabetes-related complications were also obtained from published sources. Treatment costs were derived from Danish official sources. Scenario analyses were also performed to test the accuracy of the base case results.

RESULTS

Individuals with T2D on SC semaglutide plus metformin gained 0.065 life-years (LYs) and 0.130 quality-adjusted LYs (QALYs), respectively, at an incremental cost of DKK 96,923 (€ 13,031) compared to empagliflozin plus metformin, resulting in an incremental cost-effectiveness ratio (ICER) of DKK 745,561(€ 100,239) per QALY gained. The probabilistic sensitivity analysis (PSA) results showed that the SC semaglutide plus metformin was cost-effective in 19% of simulations assuming a willingness-to-pay (WTP) threshold of DKK 357,100 (€ 48,011)/QALY gained. Duration of therapy with SC semaglutide seems the key driver of results.

CONCLUSION

The current analyses suggest that SC semaglutide plus metformin is not cost-effective compared to empagliflozin plus metformin from a Danish payer's perspective.

Diabetic Gastroenteropathy: Soothe the Symptoms or Unravel a Cure?

Autonomic neuropathy in patients with diabetes mellitus, and especially complications related to gastrointestinal neuropathy, are often overlooked in the clinic. Diabetic gastroenteropathy affects every segment of the gastrointestinal tract and generates symptoms that may include nausea, early satiety, vomiting, abdominal pain, constipation, and diarrhea. Severe cases can be complicated by weight loss, dehydration, and electrolyte disturbances. The pathophysiology is complex, the diagnostics and treatment options are multidisciplinary, and there is generally a lack of evidence for the treatment options. The aims for this review are first to summarize the pathophysiology and describe possible and expected symptoms and complications.Further, we will try to supply the clinician with a straightforward tool for diagnostics, and then, we shall summarize established treatment options, including diet recommendations, pharmacological and non-pharmacological options. Finally, we will explore the multiple possibilities of novel treatment, looking at medications related to the pathophysiology of neuropathy, other manifestations of autonomic neuropathies, and symptomatic treatment for other gastrointestinal disorders, also including new knowledge of endosurgical and neuromodulatory treatment. The overall goal is to increase awareness and knowledge on this frequent diabetic complication and to provide better tools for diagnosis and treatment. Ultimately, we hope to encourage further research in this field, as there are clear shortcomings in terms of biomarkers, pathophysiology, as well as treatment possibilities. In conclusion, diagnosis and management of diabetic gastroenteropathy are challenging and often require multidisciplinary teams and multimodal therapies. Treatment options are sparse, but new pharmacological, endoscopic, and neuromodulatory techniques have shown promising results in initial studies.

Diabetic Peripheral Neuropathy

Diabetic painless and painful peripheral neuropathy remains the most frequent complication of diabetes mellitus, but the pathophysiology remains undescribed, there are no robust clinical endpoints and no efficient treatment exists. This hampers good clinical practice, fruitful clinical research and successful pharmacological trials, necessary for the development of early detection, prevention and treatment. This chapter supplies an update on background and treatment of diabetic peripheral neuropathy. Goals and perspectives for future clinical and scientific approaches are also described.

The cost-effectiveness of oral semaglutide versus empagliflozin in Type 2 diabetes in Denmark

Aim: To evaluate the cost-effectiveness of oral semaglutide+metformin versus empagliflozin+metformin in people with Type 2 diabetes uncontrolled on msetformin alone. Materials and methods: The IQVIA Core Diabetes Model was populated with efficacy data from a head-to-head study between oral semaglutide+metformin and empagliflozin+metformin. Danish costs and quality-of-life data were sourced from literature. Price per day was Danish Krone (DKK) 25.53 for oral semaglutide and DKK11.40 for empagliflozin. Discounting was fixed at 4%. Scenario and sensitivity analyses were performed. Results: Over a lifetime, Core Diabetes Model projected 8.78 and 8.75 quality-adjusted life-years and a total cost of DKK 447,633 and DKK 387,786, thereby generating an incremental cost-effectiveness ratio of DKK 1,930,548 for oral semaglutide+metformin versus empagliflozin+metformin. Scenario and sensitivity analyses showed the robustness of the outcomes. Duration of treatment with oral semaglutide is the key driver of the analyses. Conclusion: Oral semaglutide+metformin seems not cost effective versus empagliflozin+metformin in patients uncontrolled on metformin in Denmark.

Feasibility and Acceptability of a Digital Patient-Reported Outcome Tool in Routine Outpatient Diabetes Care: Mixed Methods Formative Pilot Study

Background

Improvements in the digital capabilities of health systems provide new opportunities for the integration of patient-reported outcome (PRO) solutions in routine care, which can facilitate the delivery of person-centered diabetes care. We undertook this study as part of our development of a new digital PRO diabetes questionnaire and clinical dialog support tool for use by people with diabetes and their health care professionals (HCPs) to improve person-centered diabetes care quality and outcomes.

Objective

This study evaluates the feasibility, acceptability, and perceived benefits and impacts of using a digital PRO diabetes tool, DiaProfil, in routine outpatient diabetes care.

Methods

Overall, 12 people with diabetes scheduled for routine medical diabetes visits at the outpatient clinic were recruited. Purposive sampling was used to optimize heterogeneity regarding age, gender, duration, type of diabetes, treatment modality, and disease severity. Participants filled out a PRO diabetes questionnaire 2 to 5 days before their visit. During the visit, HCPs used a digital PRO tool to review PRO data with the person with diabetes for collaborative care planning. Participants completed evaluation forms before and after the visit and were interviewed for 30 to 45 minutes after the visit. HCPs completed the evaluation questionnaires after each visit. All visits were audio-recorded and transcribed for analysis. Data were analyzed using quantitative, qualitative, and mixed methods analyses.

Results

People with diabetes found the PRO diabetes questionnaire to be relevant, acceptable, and feasible to complete from home. People with diabetes and HCPs found the digital PRO tool to be feasible and acceptable for use during the diabetes visit and would like to continue using it. HCPs were able to use the tool in a person-centered manner, as intended. For several people with diabetes, completion of the questionnaire facilitated positive reflection and better preparation for the visit. The use of the PRO tool primarily improved the quality of the dialog by improving the identification and focus on the issues most important to the person with diabetes. People with diabetes did not report any negative aspects of the PRO tool, whereas HCPs highlighted that it was demanding when the person with diabetes had many PRO issues that required attention within the predefined time allocated for a visit.

Conclusions

The Danish PRO diabetes questionnaire and the digital tool, DiaProfil, are feasible and acceptable solutions for routine diabetes visits, and this tool may generate important benefits related to advancement of person-centered care. Further research is now required to corroborate and expand these formative insights on a larger scale and in diverse health care settings. The results of this study are therefore being used to define research hypotheses and finalize real-world PRO evaluation tools for a forthcoming large-scale multisector implementation study in Denmark.

The participatory development of a national core set of person-centred diabetes outcome constructs for use in routine diabetes care across healthcare sectors

BACKGROUND

This study sought to utilise participatory research methods to identify the perspectives of people with diabetes regarding which diabetes outcomes were most important to them. These findings were then used to support an expert working group representing multiple health sectors and healthcare disciplines and people with diabetes to establish a core set of patient-important outcome constructs for use in routine diabetes care.

METHODS

26 people with diabetes and family members were recruited through purposive sampling to participate in interviews, focus groups, voting and plenary activities in order to be part of identifying outcome constructs. Content and qualitative analysis methods were used with literature reviews to inform a national multi-stakeholder consensus process for a core set of person-centred diabetes outcome constructs to be used in routine diabetes care across health care settings.

RESULTS

21 people with diabetes and 5 family members representing type 1 and 2 diabetes and a range of age groups, treatment regimens and disease burden identified the following patient-reported outcome constructs as an important supplement to clinical indicators for outcome assessment in routine diabetes care: self-rated health, psychological well-being, diabetes related emotional distress and quality of life, symptom distress, treatment burden, blood sugar regulation and hypoglycemia burden, confidence in self-management and confidence in access to person-centred care and support. Consensus was reached by a national multi-stakeholder expert group to adopt measures of these constructs as a national core diabetes outcome set for use in routine value-based diabetes care.

CONCLUSIONS

We found that patient-reported outcome (PRO) constructs and clinical indicators are needed in core diabetes outcome sets to evaluate outcomes of diabetes care which reflect key needs and priorities of people with diabetes. The incorporation of patient-reported outcome constructs should be considered complementary to clinical indicators in multi-stakeholder value-based health care strategies. We found participatory research methods were useful in facilitating the identification of a core prioritised set of diabetes outcome constructs for routine value-based diabetes care. The use of our method for involving patients may be useful for similar efforts in other disease areas aimed at defining suitable outcomes of person-centred value-based care. Future research should focus on developing acceptable and psychometrically valid measurement instruments to evaluate these outcome constructs as part of routine diabetes care.

The Cost-Effectiveness of Empagliflozin Versus Liraglutide Treatment in People with Type 2 Diabetes and Established Cardiovascular Disease

INTRODUCTION

The increasing financial burden associated with diabetes treatment presents a challenge to healthcare systems worldwide. Recently, clinical guidelines have focussed on patients with type 2 diabetes (T2D) and established cardiovascular disease (CVD) and recommend a sodium-glucose co-transporter 2 (SGLT2) inhibitor or a glucagon-like peptide 1 (GLP-1) receptor agonist as second-line treatment after metformin or independently of baseline glycated haemogloblin A1c (HbA1c). In Danish clinical guidelines, empagliflozin and liraglutide are highlighted owing to their positive impact on mortality. Thus, this study aimed to assess the cost-effectiveness of empagliflozin plus standard of care (SoC) versus liraglutide plus SoC in Danish patients with T2D and established CVD using a lifetime and 5-year horizon.

METHODS

The IQVIA Core Diabetes Model (CDM) was calibrated to reproduce the clinical event rates observed in the cardiovascular outcome trial EMPA-REG OUTCOME. Network meta-analysis provided the relative risks for cardiovascular outcomes with empagliflozin versus liraglutide. Microvascular outcomes were predicted by standard CDM risk equations. The relative treatment effect was assumed for 9 years after which treatment was switched to basal-bolus therapy. The CDM was populated with Danish costs of events and drug costs at price-level 2019. Discounting of 4% was applied.

RESULTS

Over a lifetime horizon, CDM projected 9.858 and 9.667 life years, 6.162 and 5.976 quality-adjusted life years (QALY) and DKK 478,026 (€64,079) and DKK 500,025 (€67,027) in total costs for empagliflozin plus SoC and liraglutide plus SoC, respectively. For a 5-year horizon, the results were 4.189 and 4.140 life years, 2.746 and 2.655 QALY, as well as DKK 123,413 (€16,543) and DKK 161,783 (€21,687), respectively. Empagliflozin was the dominant treatment alternative. Sensitivity analyses showed the robustness of these results.

CONCLUSION

The cost-effectiveness analysis suggests that empagliflozin plus SoC is dominant compared to liraglutide plus SoC in Denmark over both lifetime and 5-year horizons.

Use of Sodium-Glucose Co-Transporter-2-Inhibitors (SGLT2-Is) and Risk of Lower Limb Amputation

BACKGROUND

Treatment with sodium-glucose co-transporter-2-inhibitors (SGLT2-Is), such as canagliflozin, has been associated with an increased risk of lower limb amputations (LLAs) in type 2 diabetes mellitus (T2DM). However, conflicting results have been reported for different SGLT2-Is and the underlying mechanism is unclear.

OBJECTIVE

To investigate the risk of LLA and diabetic foot ulcer with SGLT2-I use compared to other anti-diabetic drugs and to explore hypovolemia as a potential underlying mechanism.

METHODS

A cohort study was conducted using data from the Clinical Practice Research Datalink GOLD (2013-2019). The study population (N=51,847) consisted of T2DM patients over 18 years of age with at least one prescription of a non-insulin anti-diabetic drug. Concomitant diuretic use and the presence of signs of hypovolemia were determined to assess the potential underlying mechanism. Cox proportional hazard models were used to estimate the hazard ratio (HR) for LLA in current SGLT2-I use versus current sulphonylurea (SU) use. Analyses were adjusted for lifestyle variables, comorbidities, and concomitant drug use.

RESULTS

Current SGLT2-I use was not associated with an increased risk of LLA compared to current SU use (fully adjusted HR 0.70; 95% confidence interval 0.38-1.29). Concomitant use of diuretics and the presence of signs of hypovolemia were not associated with an increased risk of LLA.

CONCLUSION

Use of SGLT2-Is, with or without signs of hypovolemia, was not associated with an increased risk of LLA or DFU versus current SU use. Future studies powered to detect potential differences between individual SGLT2-Is are required to rule out a canagliflozin-specific effect.

Gastrointestinal symptoms and cardiac vagal tone in type 1 diabetes correlates with gut transit times and motility index

BACKGROUND

Although gastrointestinal (GI) symptoms are common in diabetes, they frequently do not correlate with measurable sensorimotor abnormalities. The wireless motility capsule (WMC) measures pressure, temperature, and pH as it traverses the GI tract wherefrom transit times and motility indices are derived. The aim was to investigate whether GI symptoms correlate with changes in (a) segmental transit times, (b) segmental motility index, (c) cardiac vagal tone, or (d) presence/absence of peripheral neuropathy in type 1 diabetes.

METHODS

Gastrointestinal symptoms in 104 participants with type 1 diabetes were measured using Gastroparesis Cardinal Symptoms Index and Gastrointestinal Symptom Rating Scale. All underwent standardized WMC investigation measuring segmental transit time and motility. Cardiac vagal tone and presence of peripheral neuropathy were measured using electrocardiographic and nerve conduction velocity testing.

KEY RESULTS

Colonic transit time was correlated with postprandial fullness (P = .01) and constipation (P = .03), while decreased colonic motility index was correlated with diarrhea (P = .01) and decreased bloating (P < .05). Symptoms were not correlated with gastric or small bowel transit time or motility index. In participants with low cardiac vagal tone, gastric motility index (P < .01) and colonic transit time (P < .05) were increased, but not in those with peripheral neuropathy. Abdominal pain was decreased with both peripheral neuropathy (P = .04) and decreased cardiac vagal tone (P = .02).

CONCLUSIONS AND INFERENCES

This study supports the rationale for whole gut investigation, using not only transit times but incorporating contractility indices as well. Furthermore, a decreased parasympathetic modulation and an increased hyposensate state appear to be present in type 1 diabetes.

Cardiac vagal tone as a novel screening tool to recognize asymptomatic cardiovascular autonomic neuropathy: Aspects of utility in type 1 diabetes

AIMS

To test the performance of the cardiac vagal tone (CVT) derived from a 5-minute ECG recording compared with the standardized cardiovascular autonomic reflex tests (CARTs).

METHODS

Cross-sectional study included 56 well-phenotyped adults with type 1 diabetes (19-71 years, 2-54 years disease-duration). Autonomic testing included: standardized CARTs obtained with the VAGUS™, CVT, and indices of heart rate variability (HRV) obtained at 24- and 120-hour, and electrochemical skin conductance assessed with SUDOSCAN®. ROC AUC and cut-off values were calculated for CVT to recognize CAN based on ≥ 2 (established CAN, n = 7) or 1 (borderline CAN, n = 9) abnormal CARTs and compared to HRV indices and electrochemical skin conductance.

RESULTS

Established CAN: The cut-off CVT value of 3.2LVS showed 67% sensitivity and 87% specificity (p = 0.01). Indices of HRV at either 24-hour (AUC > 0.90) and 120-hour (AUC > 0.88) performed better than CVT. Borderline CAN: The cut-off CVT value of 5.2LVS indicated 88% sensitivity and 63% specificity (p = 0.07). CVT performed better than HRV indices (AUC < 0.72). Electrochemical skin conductance (AUC:0.63-0.72) had lower sensitivity and specificity compared with CVT.

CONCLUSIONS

Implementation of CVT with a clinically applicable cut-off value may be considered a quicker and accessible screening tool which could ultimately decrease the number of unrecognized CAN and initiate earlier prevention initiatives.

Twenty years with diabetes and amputations: a retrospective population-based cohort study

AIM

To investigate the trends in non-traumatic lower limb amputation in people with and without diabetes.

METHODS

From the Danish National Patient Register, all people with either type 1 or type 2 diabetes (n = 462 743) as well as a group of people without diabetes from the general population (n = 1 388 886) were identified and separated into three groups based on diabetes type. Among these, 17 265 amputations were identified between 1997 and 2017 and stratified into trans-femoral amputations, trans-tibial amputations and amputations below the ankle using surgical codes. Annual changes were described using least-squares linear regression.

RESULTS

The yearly mean decrease in incidence rate of amputation per 1000 person-years was -0.032 [95% CI: -0.062, -0.001], -0.022 [-0.032, -0.012] and -0.006 [-0.009, -0.003] for trans-femoral amputation, -0.072 [-0.093, -0.052], -0.090 [-0.102, -0.078] and -0.015 [-0.016, -0.013] for trans-tibial amputation, and -0.055 [-0.080, -0.020], -0.075 [-0.090, -0.060] and -0.011 [-0.014, -0.007] for amputation below the ankle in people with type 1 diabetes, people with type 2 diabetes and people without diabetes, respectively.

CONCLUSIONS

Over recent decades, the incidence of amputation has decreased significantly in people with diabetes and in the general population without diabetes.

Increased levels of inflammatory factors are associated with severity of polyneuropathy in type 1 diabetes

OBJECTIVE

Distal symmetrical polyneuropathy (DSPN) is a severe common long-term complication of type 1 diabetes caused by impaired sensory-motor nerve function. As chronic low-grade inflammation may be involved in the pathogenesis of DSPN, we investigated the circulating levels of inflammatory markers in individuals with type 1 diabetes with and without DSPN. Furthermore, we determined to what extent these factors correlated with different peripheral sensory nerve functions.

DESIGN

Cross-sectional study.

PATIENTS

The study included 103 individuals with type 1 diabetes with (n = 50) and without DSPN (n = 53) as well as a cohort of healthy controls (n = 21).

MEASUREMENTS

Circulating levels of various inflammatory markers (cytokines, chemokines and soluble adhesion molecules) were determined in serum samples by Luminex multiplexing technology. Peripheral sensory nerve testing, for example vibration, tactile and thermal perception, was assessed by standardized procedures.

RESULTS

The cytokines IL-1α, IL-4, IL-12p70, IL-13, IL-17A and TNF-α; the chemokine MCP-1; and the adhesion molecule E-selectin were significantly increased in individuals with type 1 diabetes with DSPN compared to those without DSPN (P < .001). These observations were independent of age, sex, BMI, disease duration and blood pressure. Additionally, higher serum concentrations of cytokines and chemokines were associated with higher vibration and tactile perception thresholds, but not with heat tolerance threshold.

CONCLUSIONS

Individuals with type 1 diabetes and concomitant DSPN display higher serum levels of several inflammatory markers. These findings support that systemic low-grade inflammation may play a role in the pathogenesis of DSPN.

Diabetic Peripheral Neuropathy: Diagnosis and Treatment

BACKGROUND

Diabetic peripheral neuropathy (DPN) is traditionally divided into large and small fibre neuropathy (SFN). Damage to the large fibres can be detected using nerve conduction studies (NCS) and often results in a significant reduction in sensitivity and loss of protective sensation, while damage to the small fibres is hard to reliably detect and can be either asymptomatic, associated with insensitivity to noxious stimuli, or often manifests itself as intractable neuropathic pain.

OBJECTIVE

To describe the recent advances in both detection, grading, and treatment of DPN as well as the accompanying neuropathic pain.

METHODS

A review of relevant, peer-reviewed, English literature from MEDLINE, EMBASE and Cochrane Library between January 1st 1967 and January 1st 2020 was used.

RESULTS

We identified more than three hundred studies on methods for detecting and grading DPN, and more than eighty randomised-controlled trials for treating painful diabetic neuropathy.

CONCLUSION

NCS remains the method of choice for detecting LFN in people with diabetes, while a gold standard for the detection of SFN is yet to be internationally accepted. In the recent years, several methods with huge potential for detecting and grading this condition have become available including skin biopsies and corneal confocal microscopy, which in the future could represent reliable endpoints for clinical studies. While several newer methods for detecting SFN have been developed, no new drugs have been accepted for treating neuropathic pain in people with diabetes. Tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors and anticonvulsants remain first line treatment, while newer agents targeting the proposed pathophysiology of DPN are being developed.

Diffusion tensor imaging MR Neurography detects polyneuropathy in type 2 diabetes

AIM

To evaluate if diffusion-tensor-imaging MR-Neurography (DTI-MRN) can detect lesions of peripheral nerves due to polyneuropathy in patients with type 2 diabetes.

METHODS

Ten patients with type 2 diabetes with polyneuropathy (DPN), 10 patients with type 2 diabetes without polyneuropathy (nDPN) as well as 20 healthy controls (HC) were included. DTI-MRN covered proximal (sciatic nerve) and distal regions (tibial nerve) of the lower extremity. Fractional-anisotropy (FA) and diffusivity (mean (MD), axial (AD) and radial (RD)) were calculated and compared to neuropathy severity. Conventional T2-relaxation-time and proton-spin-density data were obtained from a multi-echo SE sequence. Furthermore, we evaluated sensitivity and specificity of DTI-MRN from receiver operating characteristics (ROC).

RESULTS

The proximal and distal FA was lowest in patients with DPN compared with nDPN and HC (p < 0.01). Likewise, proximal and distal RD was highest in patients with DPN (p < 0.01). MD and AD were also significantly different though less pronounced. ROC curve analyses of DTI separated nDPN and DPN with area-under-the-curve values ranging from 0.65 to 0.98. T2-relaxation-time and proton-spin-density could not differentiate between nDPN and DPN.

CONCLUSION

DTI-MRN accurately detects DPN by lower nerve FA and higher RD. These alterations are likely to reflect both proximal and distal nerve fiber pathology in patients with type 2 diabetes.

Insulin-Based Infusion System: Preliminary Study

BACKGROUND

Optimal glucose control has been shown to be useful in critical care as well as in other settings. Glucose concentrations in patients admitted to critical care are characterized by marked variability and hypoglycemia due to inadequate sensing and treatment technologies.

METHODS

The insulin balanced infusion system (IBIS) is a closed-loop system that uses a system controller, two syringe pumps, and capillary glucose sensor intravenously infusing regular insulin and/or dextrose. The IBIS performance was evaluated in terms of glucose stability in response to various conditions in subjects with type 1 and insulin requiring type 2 diabetes mellitus (n = 15) with frequent intermittent capillary measurements, entered into the system and an adaptive algorithm adjusting the treatment modalities without other nursing intervention.

RESULTS

Target glucose concentrations (80-125 mg/dl) were achieved from hyperglycemic levels in 2.49 hours in the first study with mean and standard deviation of 105.2 mg/dl and 11.5 mg/dl, respectively.

CONCLUSION

Preliminary studies using a prototype closed-loop glucose control system for critical care produced noticeable results. Improvements were initiated within the system and further studies performed.

Insulin-Based Infusion System: Advancing the Development

BACKGROUND

Deviations in glucose control in critical care have been shown to increase mortality and morbidity. However, optimal glucose control through present technologies has shown to be a challenge. The insulin balanced infusion system (IBIS) is a new and emerging technology.

METHODS

The closed loop system was tested in a stress trial to evaluate glucose stability in response to various conditions in nonrandomized people with type 1 diabetes mellitus (n=12). The prototype used in this trial was based on intermittent capillary measurements.

RESULTS

Induced stresses in the study using unpredicted stimuli of intravenous or oral glucose and intravenous insulin boluses, was contained with glucose remaining in target 43.8% of the time. Mean increase in glucose concentration after glucose load was 17.4 mg/dl; after insulin bolus, no hypoglycemia (blood glucose less than 70 mg/dl) occurred.

CONCLUSION

The use of IBIS proved safe and feasible under a wide range of conditions. The sensing and stress response of the IBIS demonstrated noticeable features.

Can the Routine Use of Patient-Reported Outcome Measures Improve the Delivery of Person-Centered Diabetes Care? A Review of Recent Developments and a Case Study

PURPOSE OF REVIEW

In recent years, the recommendation for and use of patient-reported outcome measures (PROMs) in routine diabetes care has significantly increased. We review recent evidence and highlight key opportunities and challenges related to the active clinical use of PROMs to support person-centered diabetes care and focus areas for future research in the area.

RECENT FINDINGS

Recent pragmatic studies support that integration of multi-dimensional PROMs for diabetes in clinical care as part of a care improvement strategy can be acceptable for and valued by people with diabetes (PWD) and healthcare professionals (HCPs) and may improve multiple aspects of quality of care, including screening, medical care monitoring and decision support, individualization of self-management support and goal-setting, and broader benefits related to active patient participation and person-centred diabetes care. We identify multiple intervention, individual, and care setting characteristics, which influence acceptability, feasibility, implementation, and effectiveness of PROMs in routine care. Recent clinical PROM studies highlight the value of mixed methods research and systematic involvement of PWD, clinicians, and other stakeholders in the design and implementation of questionnaires for patient input in routine diabetes care. We identified a new significant trend towards participatory development of multi-dimensional PROMs with the aim of IT-enabled integration into routine diabetes care to facilitate multiple components of person-centered diabetes care and better clinical, quality of life, and cost outcomes. While results from large-scale randomized controlled studies are still limited, a growing number of pragmatic implementation studies support that user-centric PROM interventions have the potential to facilitate significant improvements in care for PWD.

Early Assessment of Cost-effectiveness of Gastric Electrical Stimulation for Diabetic Nausea and Vomiting

Background/Aims

Recurrent nausea and/or vomiting are common complications of diabetes mellitus. The conditions severely impact the quality of life of patients and often cause repeated admissions to hospital incurring significant healthcare costs. If standard treatment fails, gastric electrical stimulation (GES) may be offered in selected cases, as a minimally invasive, but expensive, therapeutic option. Our aims are to evaluate the clinical effect and the cost-utility of GES as a treatment for severe diabetic recurrent nausea and/or vomiting.

Methods

Among 33 diabetes patients implanted with GES because of recurrent nausea and/or vomiting, 30 were available for evaluation. The effect of treatment was assessed prospectively using symptom-diaries and the SF-36 questionnaires at baseline, after 6 and 12 months, and thereafter yearly. The number of days in hospital due to symptoms related to gastrointestinal dysfunction was calculated using hospital records 12 months prior to and 12 months after implantation.

Results

The surgical procedures were performed without mortality or major complications. Six months after surgery 78% of the respondents had at least 50% reduction in time with nausea and 48% had at least 50% reduction in days with vomiting. Symptom relief persisted at follow-up after at least 4 years. Quality adjusted life years improved after GES, which was cost-effective after 24 months.

Conclusions

GES reduces symptoms and improves quality of life in diabetes patients with recurrent nausea and/or vomiting. The procedure is supposed as cost-effective over a 2-year time horizon.

Magnetic Resonance Neurography Visualizes Abnormalities in Sciatic and Tibial Nerves in Patients With Type 1 Diabetes and Neuropathy

This study evaluates whether diffusion tensor imaging magnetic resonance neurography (DTI-MRN), T2 relaxation time, and proton spin density can detect and grade neuropathic abnormalities in patients with type 1 diabetes. Patients with type 1 diabetes (n = 49) were included-11 with severe polyneuropathy (sDPN), 13 with mild polyneuropathy (mDPN), and 25 without polyneuropathy (nDPN)-along with 30 healthy control subjects (HCs). Clinical examinations, nerve conduction studies, and vibratory perception thresholds determined the presence and severity of DPN. DTI-MRN covered proximal (sciatic nerve) and distal (tibial nerve) nerve segments of the lower extremity. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were calculated, as were T2 relaxation time and proton spin density obtained from DTI-MRN. All magnetic resonance findings were related to the presence and severity of neuropathy. FA of the sciatic and tibial nerves was lowest in the sDPN group. Corresponding with this, proximal and distal ADCs were highest in patients with sDPN compared with patients with mDPN and nDPN, as well as the HCs. DTI-MRN correlated closely with the severity of neuropathy, demonstrating strong associations with sciatic and tibial nerve findings. Quantitative group differences in proton spin density were also significant, but less pronounced than those for DTI-MRN. In conclusion, DTI-MRN enables detection in peripheral nerves of abnormalities related to DPN, more so than proton spin density or T2 relaxation time. These abnormalities are likely to reflect pathology in sciatic and tibial nerve fibers.

Magnetic resonance neurography and diffusion tensor imaging of the peripheral nerves in patients with Charcot-Marie-Tooth Type 1A

INTRODUCTION

Investigation of peripheral neuropathies by magnetic resonance neurography (MRN) may provide increased diagnostic accuracy when performed in combination with diffusion tensor imaging (DTI). This study seeks to evaluate DTI in the detection of neuropathic abnormalities in Charcot-Marie-Tooth type 1A (CMT1A).

METHODS

MRI of the sciatic and tibial nerves, including MRN and DTI, was prospectively performed in 15 CMT1A patients and 30 healthy controls (HCs). The following MRI parameters were evaluated and correlated with clinical and neurophysiological findings: T2-relaxation time, proton spin density (PD) and DTI (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]).

RESULTS

DTI showed lower FA and higher ADC in CMT1A compared with HCs. T2 relaxation time showed no difference; however, PD of the sciatic nerve was higher in CMT1A. There were some close associations between neuropathy severity and MRN-DTI, with the closest correlation between FA and nerve conduction velocity in the sciatic nerve (r = 0.76, P < 0.01).

DISCUSSION

MRN-DTI evaluation of sciatic and tibial nerves improves the detection of nerve abnormalities in patients with CMT1A. Muscle Nerve 56: E78-E84, 2017.

Euglycemic ketosis in patients with type 2 diabetes on SGLT2-inhibitor therapy-an emerging problem and solutions offered by diabetes technology

Diabetic ketoacidosis is an infrequent but life-threatening acute complication of diabetes, affecting predominantly patients with type 1 diabetes, children, and pregnant women, where ketosis is usually associated with marked hyperglycemia. Recently, an increasing number of cases have been reported of euglycemic diabetic ketoacidosis in patients with type 2 diabetes receiving sodium-glucose cotransporter 2 inhibitor treatment in routine practice. There is a minor, but not negligible diabetic ketoacidosis risk associated with this drug class, which was not seen in randomized clinical trials. However, sodium-glucose cotransporter2 inhibitors increase the risk of ketosis by increasing glucagon secretion in the pancreas and decreasing the renal excretion of 3-hydroxybutyrate and acetoacetate. When used in addition to insulin, any insulin dose reduction required to avoid hypoglycemia may lead to insufficient suppression of lipolysis and ketogenesis. sodium-glucose cotransporter2 inhibitor-induced loss of urinary glucose encourages euglycemia. Normo-glycemic or near-normoglycemic diabetic ketoacidosis represents a major threat to the health and well-being of a patient, because it may occur undetected and without any indicative hyperglycemia. In consequence, patients on sodium-glucose cotransporter2 inhibitors are recommended to perform regular blood ketone tests since they are not alerted to incipient diabetic ketoacidosis by glucose testing alone. This option is offered by several blood glucose meters that can also measure ketones with a separate ketone strip or in one case by an automatic parallel ketone assessment from the same strip. The need for extra testing and the associated costs may be a barrier to patient acceptance of this risk mitigation procedure. However, patients who are at risk for euglycemic diabetic ketoacidosis when being treated with sodium-glucose cotransporter2 inhibitors should be specially advised to monitor blood ketone levels on a regular basis.

Diffusion tensor imaging MR neurography for the detection of polyneuropathy in type 1 diabetes

PURPOSE

To evaluate if diffusion tensor imaging MR neurography (DTI-MRN) can detect lesions of peripheral nerves in patients with type 1 diabetes.

MATERIALS AND METHODS

Eleven type 1 diabetic patients with polyneuropathy (DPN), 10 type 1 diabetic patients without polyneuropathy (nDPN), and 10 healthy controls (HC) were investigated with a 3T MRI scanner. Clinical examinations, nerve-conduction studies, and vibratory-perception thresholds determined the presence of DPN. DTI-MRN (voxel size: 1.4 × 1.4 × 3 mm³ ; b-values: 0, 800 s/mm² ) covered proximal (sciatic nerve) and distal regions of the lower extremity (tibial nerve). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated and compared to T₂ -relaxometry and proton-spin density obtained from a multiecho turbo spin echo (TSE) sequence. Furthermore, we evaluated DTI reproducibility, repeatability, and diagnostic accuracy.

RESULTS

DTI-MRN could accurately discriminate between DPN, nDPN, and HC. The proximal FA was lowest in DPN (DPN 0.37 ± 0.06; nDPN 0.47 ± 0.03; HC 0.49 ± 0.06; P < 0.01). In addition, distal FA was lowest in DPN (DPN 0.31 ± 0.05; nDPN 0.41 ± 0.07; HC 0.43 ± 0.08; P < 0.01). Likewise, proximal ADC was highest in DPN (DPN 1.69 ± 0.25 × 10^-3 mm² /s; nDPN 1.50 ± 0.06 × 10^-3 mm² /s; HC 1.42 ± 0.12 × 10^-3 mm² /s; P < 0.01) as was distal ADC (DPN 1.87 ± 0.45 × 10^-3 mm² /s; nDPN 1.59 ± 0.19 × 10^-3 mm² /s; HC 1.57 ± 0.26 × 10^-3 mm² /s; P = 0.09). The combined interclass-correlation (ICC) coefficient of DTI reproducibility and repeatability was high in the sciatic nerve (ICC: FA = 0.86; ADC = 0.85) and the tibial nerve (ICC: FA = 0.78; ADC = 0.66). T₂ -relaxometry and proton-spin-density did not enable detection of neuropathy.

CONCLUSION

DTI-MRN accurately detects DPN by lower nerve FA and higher ADC. These alterations are likely to reflect proximal and distal nerve fiber pathology.

LEVEL OF EVIDENCE

1 J. Magn. Reson. Imaging 2017;45:1125-1134.

The degree of autonomic modulation is associated with the severity of microvascular complications in patients with type 1 diabetes

OBJECTIVE

The objective of this study was to elucidate whether the degree of autonomic modulation is associated with the degree of microvascular complications in patients with type 1 diabetes.

METHODS

A total of 290 type 1 individuals with diabetes were randomly recruited during normal visits to outpatient clinics at 4 Danish hospitals. The degree of autonomic modulations was quantified by measuring heart rate variability (HRV) during passive spectral analysis and active tests (valsalva ratio [VT], response to standing [RT], and deep breathing [E:I]). To describe possible associations between severity of microvascular complications and measures of autonomic modulation, multivariate analysis was performed.

RESULTS

After adjusting for diabetes duration, sex, age, pulse pressure, heart rate, and smoking, autonomic dysfunction remained significantly correlated with severity of retinopathy, nephropathy, and peripheral neuropathy in individuals with type 1 diabetes patients.

CONCLUSIONS

Autonomic dysfunction is present in early stages of retinopathy, nephropathy, and peripheral neuropathy in patients with type 1 diabetes.

A novel model enhances HbA1c-based diabetes screening using simple anthropometric, anamnestic, and demographic information

BACKGROUND

The sensitivity of HbA1c is not optimal for the screening of patients with latent diabetes. We hypothesize that simple healthcare information could improve accuracy.

METHODS

We retrospectively analyzed data, including HbA1c, from multiple years from the National Health and Nutrition Examination Survey (NHANES) database (2005-2010). The data were used to create a logistic regression classification model for screening purposes.

RESULTS

The study evaluated data for 5381 participants, including 404 with undiagnosed diabetes. The HbA1c screening data were supplemented with information about age, waist circumference, and physical activity in the HbA1c+ model. Alone, HbA1c alone had a receiver operating characteristics (ROC) curve for the area under the curve (AUC) of 0.808 (95% confidence interval [CI] 0.792-0.834). The HbA1c+ model had an ROC AUC of 0.851 (95% CI 0.843-0.872). There was a significant difference in the AUC between our model and using HbA1c without supplementary information (P < 0.05).

CONCLUSIONS

We have developed a novel screening model that could help improve screening for type 2 diabetes with HbA1c. It seems beneficial to systematically add additional patient healthcare information in the process of screening with HbA1c.

Cardiovascular autonomic neuropathy is associated with macrovascular risk factors in type 2 diabetes: new technology used for routine large-scale screening adds new insight

The objective was to identify the presence of cardiovascular autonomic neuropathy (CAN) in a cohort of individuals with diabetes in outpatient clinics from 4 different parts of Denmark and to explore the difference between type 1 and type 2 diabetes in relation to CAN. The DAN-Study is a Danish multicenter study focusing on diabetic autonomic neuropathy. Over a period of 12 months, 382 type 1 and 271 type 2 individuals with diabetes were tested for CAN. Patients were randomly recruited and tested during normal visits to outpatient clinics at 4 Danish hospitals. The presence of CAN was quantified by performing 3 cardiovascular reflex tests (response to standing, deep breathing, and valsalva). To describe possible associations, multivariate analysis with CAN as the dependent variable was performed. The prevalence of CAN was higher among patients with type 2 diabetes (35%) compared to patients with type 1 diabetes (25%). Multivariate analysis revealed significant associations between CAN and different risk markers in the 2 populations. In type 1 diabetes patients CAN was associated with microalbuminuria (P < .001), macroalbuminuria (P = .011), simplex retinopathy (P < .001), proliferative retinopathy (P < .001), and peripheral neuropathy (P = .041). Among type 2 diabetes patients CAN was independently associated with high pulse pressure (P < .01), BMI (P = .006), and smoking (P = .025). In this cross-sectional observational study CAN was independently associated with microvascular complication in type 1, whereas in type 2 CAN was associated with macrovascular risk factors.

Improved diabetes screening using an extended predictive feature search

BACKGROUND

Screening entire populations for diabetes is not cost-effective. Hence, an efficient screening process must select those people who are at high risk for diabetes. In this study, we investigated whether screening procedures could be improved using an extended predictive feature search.

MATERIALS AND METHODS

In order to develop our model and identify persons with diabetes (prevalence) we used data from years of the National Health and Nutrition Examination Survey (2005-2010), which has not been explored for this purpose before. We calculated all combinations of predictors in order to identify the optimal subset, and we used a linear logistic classification model to predict diabetes. V-fold cross-validation was used for the process of including variables and for validating the final models. This new model was compared with two established models.

RESULTS

In total, 5,398 participants were included in this study. Among these, 478 participants had unidentified diabetes. The established models had a receiver operating characteristics curve for the area under the curve (AUC) of 0.74 and 0.71 compared with an AUC of 0.78 for the new model, showing a significant difference (P<0.05). A proposed cutoff point for the established models yielded respective sensitivities/specificities of 63%/72% and 40%/72% compared with the new model, which had a sensitivity/specificity of 70%/72%.

CONCLUSIONS

Our data indicate that simple healthcare and economic information such as ratio of family income to poverty can add value in deciding who is at risk of unknown diabetes by using extended investigations of predictor combinations.

Phase 2b, randomized, double-blind 12-week studies of TZP-102, a ghrelin receptor agonist for diabetic gastroparesis

BACKGROUND

TZP-102, a potent, oral, ghrelin receptor agonist, improved diabetic gastroparesis symptoms in Phase 2a.

METHODS

Patients with type 1 or 2 diabetes, delayed gastric half-emptying (T(1/2)), and ≥3 months gastroparesis symptoms randomized 1 : 1 : 1 to double-blind placebo, 10-mg, or 20-mg TZP-102 once daily for 12 weeks (Study TZP-102-CL-G003). Study TZP-102-CL-G004 patients randomized 1 : 1 to 10-mg TZP-102:placebo three-times-daily. Primary endpoint was change-from-baseline through Weeks 11-12 in Daily Diary of Gastroparesis Symptoms Questionnaire (GSDD) via electronic Patient Recorded Outcome device: worst severity of nausea, early satiety, bloating, and upper abdominal pain in 24 h (0 = none-to-5 = very severe). GSDD Composite Score for eligibility was ≥2.5 (Day-14-to-baseline). Patient Overall Treatment Evaluation (OTE) provided an anchor-based minimal clinically important difference (MCID) for GSDD Composite Score.

KEY RESULTS

Study TZP-102-CL-G003 enrolled 201 outpatients: females 72%; Caucasians 87%; type 2 diabetes 61%; insulin-dependent 65%; age mean ± SD 53 ± 11.3 years; HbA1c 7.8 ± 1.5%; GCSI 3.4 ± 0.7; GSDD Composite 3.6 ± 0.6; gastric T1/2 131 ± 32 min; n = 69 (10-mg), n = 66 (20-mg), n = 66 (placebo). Primary endpoint (GSDD): significant improvement in all arms, although not for TZP-102 vs placebo: mean change-from-baseline -1.7, -1.4, -1.5 (10-mg, 20-mg, placebo); Gastroparesis Cardinal Symptom Index -1.8, -1.6, -1.5, respectively. The OTE (all patients) at Week-12 was: Patient 3.7 ± 3.2 and Physician 3.6 ± 3.0 with median score for both of 5.0 = important on scale of improvement; individual MCID was 1.61 and 0.94 for group analyses, greater than expected. Study TZP-102-CL-G004 with similar demographic/disease characteristics was prematurely terminated for efficacy futility (n = 64 with Week-4 assessments).

CONCLUSIONS & INFERENCES

Efficacy of TZP-102 was not demonstrated compared with placebo in diabetic gastroparesis; however, there was substantial symptom improvement in all arms (ClinicalTrials.gov NCT01452815/NCT01664637).

A phase 2a, randomized, double-blind 28-day study of TZP-102 a ghrelin receptor agonist for diabetic gastroparesis

BACKGROUND

Gastroparesis causes significant morbidity and treatment options are limited. TZP-102 a novel, macrocyclic, selective, oral ghrelin receptor agonist, was evaluated in a randomized, double-blind, placebo-controlled trial in patients with diabetic gastroparesis.

METHODS

A total of 92 outpatients were randomized to once-daily administrations of 10-mg (n = 22), 20-mg (n = 21), 40-mg (n = 23) TZP-102 or placebo (n = 26). The primary endpoint was the change from baseline in gastric half-emptying time (T(½)) utilizing (13)C-breath test methodology and secondary endpoints included symptom improvement using patient-reported gastroparesis symptom scores (PAGI-SYM questionnaire) and patient and physician overall treatment evaluations (OTE).

KEY RESULTS

Gastric T½ changes were not statistically significant between TZP-102 and placebo after 28 days of treatment at any dose. Clinical improvements (-1.0 to -1.4 point mean decrease in symptom severity) occurred in the Gastroparesis Cardinal Symptom Index (GCSI) component of the PAGI-SYM, which was significant vs placebo for all TZP-102 doses combined. Improvements became evident after 1 week of treatment. Significantly, more patients given TZP-102 (any dose) had a 50% reduction in baseline GCSI score (28.8%vs 7.7% placebo). Safety profiles were similar across groups. All TZP-102 doses were well-tolerated with no adverse cardiac, weight, or glucose control outcomes.

CONCLUSIONS & INFERENCES

TZP-102 for 28 days, at doses of 10-40 mg once daily, was well-tolerated and resulted in a reduction in symptoms of gastroparesis. The lack of correlation between symptom improvement and gastric emptying change is consistent with previous studies in diabetic gastroparesis, and emphasizes the value of patient-defined outcomes in determining therapeutic benefit.

Assessment of postprandial glucose excursions throughout the day in newly diagnosed type 2 diabetes

BACKGROUND

A growing body of evidence suggests that postprandial glucose (PPG) is independently linked to multiple complications and that testing of PPG should be added to hemoglobin A1c (HbA1c) and fasting glucose measurements in the evaluation of glycemic control of type 2 diabetes patients. An ongoing debate is questioning how to assess PPG. This observational study looks further into this question in a cohort of newly diagnosed type 2 diabetes patients.

SUBJECTS AND METHODS

PPG characteristics and intra-/intersubject variations post-breakfast, -lunch, and -dinner, obtained from continuous glucose monitoring (CGM), were retrospectively analyzed in 86 newly diagnosed non-insulin-treated type 2 diabetes patients.

RESULTS

In total, 462 recorded meals were analyzed. The area under the curve 1-4 h postmeal was significantly larger after breakfast compared with both lunch and dinner (P<0.001). Time to peak was approximately 90 min and did not differ significantly between meals. However, the distribution of the blood glucose peaks was only normally distributed among breakfasts, and time to peak had a day-to-day correlation coefficient of 0.60, compared with a nonsignificant result for lunch and dinner. Breakfast PPG peaks were highly correlated to HbA1c (P<0.05, r=0.64) and had a day-to-day correlation coefficient of 0.86 compared with 0.44 for lunch and 0.74 for dinner.

CONCLUSIONS

Self-monitoring of blood PPG should be evaluated with care. From our data, monitoring of PPG patterns in newly diagnosed type 2 diabetes patients should preferably be obtained following breakfast for a more consistent assessment, reducing day-to-day variations.