Use of the Michigan Neuropathy Screening Instrument as a measure of distal symmetrical peripheral neuropathy in Type 1 diabetes: results from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications

Standing Balance Performance and Knee Extensors' Strength in Diabetic Patients with Neuropathy

Diabetes peripheral neuropathy (DPN) leads to balance impairment among diabetes mellitus (DM). The aims of this study were to (1) distinguish between DM patients who have/do not have DPN and to (2) compare quadriceps' strength and balance performance of DM, DPN, and healthy groups. Fifteen healthy females and 33 females with type 2 diabetic patients participated. The electrodiagnostic method was used to classify diabetic patients into DM and DPN. A dynamometer was used to measure quadriceps' strength. Single-leg standing on a force plate was also used to quantify participants' balance. Smaller conduction velocity and amplitude and greater distal latency of all nerves were observed in the DPN compared with the DM in particular for sensory nerve. In DPN, conduction velocity was asymmetrical. The quadriceps' strength of both legs in DPN and the right leg in DM was smaller than in the control group. The root mean square of the center of pressure was similar between DM and DPN. But it was larger in DPN than in the control group. DPN is associated with asymmetrical conduction velocity, smaller quadriceps' strength, and weaker balance performance that is suggestive of higher risk of falling. Balance training is recommended for the DPN group during their rehabilitation to reduce their falling risk.

Long-term symptoms of polyneuropathy in breast and colorectal cancer patients treated with and without adjuvant chemotherapy

Background

The aim of this study was to assess chemotherapy‐induced polyneuropathy (CIPN) 5 years after adjuvant chemotherapy in patients with breast and colorectal cancer. The association of CIPN with quality of life, anxiety, and depression was analyzed.

Methods

Of a set of 100 patients with breast cancer and of 74 with colorectal cancer who had undergone surgery and adjuvant chemotherapy in 2011‐2012, 80 and 52 patients alive, respectively, were included together with two reference groups of 249 breast cancer patients and 83 colorectal cancer patients who had undergone surgery only. All patients were sent a questionnaire on alcohol consumption, smoking habits, comorbidity, medicine consumption, and oxaliplatin‐specific questions, as well as the Michigan Neuropathy Screening Instrument questionnaire (MNSIq), the Douleur Neuropathique 4 Questions (DN4q), the EQ‐5D, and the Hospital Anxiety and Depression Scale. Possible polyneuropathy was defined as the presence of numbness and/or tingling in the feet, secondly as a score of ≥4 on the MNSIq. Possible painful polyneuropathy was defined as pain in both feet and a score ≥3 on the DN4q.

Results

The prevalence of possible polyneuropathy defined by numbness and/or tingling in the feet was 38.8% (28.1‐50.3) after adjuvant docetaxel and 57.7% (43.2‐71.3) after adjuvant oxaliplatin, with no significant difference from a previous 1‐year follow‐up (P >.35). Fewer had possible polyneuropathy as defined by the MNSIq. Patients with possible polyneuropathy after adjuvant chemotherapy reported significantly lower quality of life than patients treated with surgery only.

Conclusion

Symptoms of polyneuropathy following adjuvant docetaxel and oxaliplatin persist 5 years after treatment and affect quality of life negatively.

Glycaemic control for painful diabetic peripheral neuropathy is more than fasting plasma glucose and glycated haemoglobin

BACKGROUND

The relationship between postprandial hyperglycaemia and diabetic peripheral neuropathy (DPN), whether painful or painless, has yet to be determined. Thus, the aim of this study was to investigate the relationship in patients with type 2 diabetes (T2D).

METHODS

This cross-sectional study was conducted in adults with T2D between January and October 2013. Blood samples were collected after overnight fasting every 3 months prior to enrolment. For this study, increased postprandial glycaemic exposure was defined as high glycated haemoglobin (HbA_1c) and near-normal mean fasting plasma glucose (FPG) levels. Both painless and painful DPN were evaluated using two validated tools, the Michigan Neuropathy Screening Instrument (MNSI) and Douleur Neuropathique 4 (DN4) questionnaire.

RESULTS

This study included 1040 participants with mean FPG levels<140mg/dL, 535 of which were<126mg/dL. Of these patients, 200/1040 (19.2%) and 105/535 (19.6%) had DPN. Multivariate analysis demonstrated that higher HbA_1c levels (≥7%) did not increase risk of painless DPN, but did significantly increase risk of painful DPN in T2D patients with FPG<140mg/dL and<126mg/dL, with corresponding odds ratios of 2.49 and 3.77 (95% confidence intervals: 1.09-5.71 and 1.20-11.79), respectively, after adjusting for demographic factors, diabetes-related variables and comorbidities.

CONCLUSION

This study is the first to reveal that increased postprandial glycaemic exposure, as assessed by high HbA1c and near-normal FPG levels, is associated with an increased risk of painful DPN in adults with T2D.

Classical Therapies Versus Combined Therapies in Diabetic Neuropathy

The aim of our study was to evaluate the classical therapies represented by adequate glycemic control and lifestyle changes versus classical therapies combined with new antioxidant therapies in patients with diabetic neuropathy. We conducted an observational, prospective study, between October 2017 and December 2019, which included a number of 188 patients suffering from diabetic neuropathy. In order to evaluate the response to the therapeutic protocol, we used the MNSI (Michigan neuropathy screening instrument). Responder group was defined as a decrease in MNSI (<7) from baseline to one year. According to this 34.04% (n=64) of patients were responders to classical therapy while a higher number of patients responded to combined therapy (n=73, representing 38.83%). In the group of responders, the subgroups that predicted the prevention of MNSI increase (decrease in the impact of diabetic neuropathy) in the group treated with combined therapy compared to classical therapy, related to clinicopathological features, after one year included: gender female (p=0.0415), body mass index <30kg/m2 (p=0.0335), absence of cardiovascular disease (p=0.0006) and absence of dyslipidemia (p=0.0288). In conclusion, we demonstrated an increased response to combined therapy after one year of treatment. Thus, combined therapy is an alternative for reducing side effects and for increasing efficiency.

The Contemporary Prevalence of Diabetic Neuropathy in Type 1 Diabetes: Findings From the T1D Exchange

OBJECTIVE

To evaluate the contemporary prevalence of diabetic peripheral neuropathy (DPN) in participants with type 1 diabetes in the T1D Exchange Clinic Registry throughout the U.S.

RESEARCH DESIGN AND METHODS

DPN was assessed with the Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ) in adults with ≥5 years of type 1 diabetes duration. A score of ≥4 defined DPN. Associations of demographic, clinical, and laboratory factors with DPN were assessed.

RESULTS

Among 5,936 T1D Exchange participants (mean ± SD age 39 ± 18 years, median type 1 diabetes duration 18 years [interquartile range 11, 31], 55% female, 88% non-Hispanic white, mean glycated hemoglobin [HbA1c] 8.1 ± 1.6% [65.3 ± 17.5 mmol/mol]), DPN prevalence was 11%. Compared with those without DPN, DPN participants were older, had higher HbA1c, had longer duration of diabetes, were more likely to be female, and were less likely to have a college education and private insurance (all P < 0.001). DPN participants also were more likely to have cardiovascular disease (CVD) (P < 0.001), worse CVD risk factors of smoking (P = 0.008), hypertriglyceridemia (P = 0.002), higher BMI (P = 0.009), retinopathy (P = 0.004), reduced estimated glomerular filtration rate (P = 0.02), and Charcot neuroarthropathy (P = 0.002). There were no differences in insulin pump or continuous glucose monitor use, although DPN participants were more likely to have had severe hypoglycemia (P = 0.04) and/or diabetic ketoacidosis (P < 0.001) in the past 3 months.

CONCLUSIONS

The prevalence of DPN in this national cohort with type 1 diabetes is lower than in prior published reports but is reflective of current clinical care practices. These data also highlight that nonglycemic risk factors, such as CVD risk factors, severe hypoglycemia, diabetic ketoacidosis, and lower socioeconomic status, may also play a role in DPN development.

Diabetic Neuropathy Is a Substantial Burden in People With Type 1 Diabetes and Is Strongly Associated With Socioeconomic Disadvantage: A Population-Representative Study From Scotland

OBJECTIVE

To assess the contemporaneous prevalence of diabetic peripheral neuropathy (DPN) in people with type 1 diabetes (T1D) in Scotland and study its cross-sectional association with risk factors and other diabetic complications.

RESEARCH DESIGN AND METHODS

We analyzed data from a large representative sample of adults with T1D (N = 5,558). We assessed the presence of symptomatic neuropathy using the dichotomized (≥4) Michigan Neuropathy Screening Instrument Patient Questionnaire score. Logistic regression models were used to investigate associations between DPN and risk factors, as well as with other complications.

RESULTS

The burden of DPN is substantial with 13% prevalence overall. Adjusting for attained age, diabetes duration, and sex, the odds of DPN increased mainly with waist-to-hip ratio, lipids, poor glycemic control (odds ratio 1.51 [95% CI 1.21-1.89] for levels of 75 vs. 53 mmol/mol), ever versus never smoking (1.67 [1.37-2.03]), and worse renal function (1.96 [1.03-3.74] for estimated glomerular filtration rate levels <30 vs. ≥90 mL/min/1.73 m²). The odds significantly decreased with higher HDL cholesterol (0.77 [0.66-0.89] per mmol/L). Living in more deprived areas was associated with DPN (2.17 [1.78-2.65]) for more versus less deprived areas adjusted for other risk factors. Finally, individuals with prevalent DPN were much more likely than others to have other diabetes complications.

CONCLUSIONS

Diabetic neuropathy remains substantial, particularly affecting those in the most socioeconomically deprived groups. Those with clinically manifest neuropathy also have a higher burden of other complications and elevated levels of modifiable risk factors. These data suggest that there is considerable scope to reduce neuropathy rates and narrow the socioeconomic differential by better risk factor control.

Polyneuropathy in Severely Obese Women Without Diabetes: Prevalence and Associated Factors

BACKGROUND

Obesity and its complications are prevalent in women and increase with age. Polyneuropathy (PNP) is a complication of obesity and bariatric surgery (BS). In subjects with severe (grades II and III) obesity and without DM who are candidates for BS, the prevalence of PNP and associated conditions are not well characterized. The aim of this study was to evaluate the prevalence of PNP in severely obese (SO) women without DM or common nutritional deficiencies in order to determine factors associated with the presence of PNP.

METHODS

A cross-sectional study was performed on 450 SO women. They were evaluated with the Michigan Neuropathy Screening Instrument, a Sleep Apnea Questionnaire, and the short form of the International Physical Activity Questionnaire. Data on blood pressure, body mass index, waist circumference, serum glucose, glycated hemoglobin, LDL and HDL cholesterol, triglycerides, vitamin B12, and postmenopausal (PM) status were also collected. Patients with DM and other common causes of PNP were excluded. To evaluate which variables were independently associated with PNP (dependent variable), Poisson regression models were used.

RESULTS

The prevalence of PNP was 11.6%. In univariate analysis, PNP was associated with age, PM status, and diagnosis of systemic arterial hypertension (p < 0.001, p < 0.001, and p = 0.016, respectively), and there was a trend toward an association with sleep apnea risk (p = 0.101). In multivariate analysis, PM status (PR = 2.836, 95% CI 1.735-4.636, p = 0.001) and age (PR = 1.0511, 95% CI 1.031-1.071, p = 0.001) were independently associated with PNP diagnosis in two different models.

CONCLUSION

Even prior to BS, PNP is highly prevalent and is associated with PM status and age in SO women without diabetes.

Targeting the NADPH Oxidase-4 and Liver X Receptor Pathway Preserves Schwann Cell Integrity in Diabetic Mice

Diabetes triggers peripheral nerve alterations at a structural and functional level, collectively referred to as diabetic peripheral neuropathy (DPN). This work highlights the role of the liver X receptor (LXR) signaling pathway and the cross talk with the reactive oxygen species (ROS)-producing enzyme NADPH oxidase-4 (Nox4) in the pathogenesis of DPN. Using type 1 diabetic (T1DM) mouse models together with cultured Schwann cells (SCs) and skin biopsies from patients with type 2 diabetes (T2DM), we revealed the implication of LXR and Nox4 in the pathophysiology of DPN. T1DM animals exhibit neurophysiological defects and sensorimotor abnormalities paralleled by defective peripheral myelin gene expression. These alterations were concomitant with a significant reduction in LXR expression and increase in Nox4 expression and activity in SCs and peripheral nerves, which were further verified in skin biopsies of patients with T2DM. Moreover, targeted activation of LXR or specific inhibition of Nox4 in vivo and in vitro to attenuate diabetes-induced ROS production in SCs and peripheral nerves reverses functional alteration of the peripheral nerves and restores the homeostatic profiles of MPZ and PMP22. Taken together, our findings are the first to identify novel, key mediators in the pathogenesis of DPN and suggest that targeting LXR/Nox4 axis is a promising therapeutic approach.

Receipt of recommended complications and comorbidities screening in youth and young adults with type 1 diabetes: Associations with metabolic status and satisfaction with care

OBJECTIVES

This study sought to: (a) assess the prevalence of diabetes complications and comorbidities screening as recommended by the American Diabetes Association (ADA) for youth and young adults (YYAs) with type 1 diabetes (T1D), (b) examine the association of previously measured metabolic status related to diabetes complications with receipt of recommended clinical screening, and (c) examine the association of satisfaction with diabetes care with receipt of recommended clinical screening.

METHODS

The study included 2172 SEARCH for Diabetes in Youth participants with T1D (>10 years old, diabetes duration >5 years). Mean participant age was 17.7 ± 4.3 years with a diabetes duration of 8.1 ± 1.9 years. Linear and multinomial regression models were used to evaluate associations.

RESULTS

Sixty percent of participants reported having three or more hemoglobin A1c (HbA1c) measurements in the past year. In terms of diabetes complications screening, 93% reported having blood pressure measured, 81% having an eye examination, 71% having lipid levels checked, 64% having a foot exam, and 63% completing albuminuria screening in accordance with ADA recommendations. Youth known to have worse glycemic control in the past had higher odds of not meeting HbA1c screening criteria (OR 1.11, 95% CI = 1.05, 1.17); however, after adjusting for race/ethnicity, this was no longer statistically significant. Greater satisfaction with diabetes care was associated with increased odds of meeting screening criteria for most of the ADA-recommended measures.

CONCLUSIONS

Efforts should be made to improve diabetes complications screening efforts for YYAs with T1D, particularly for those at higher risk for diabetes complications.

Clinical Response to Real-Time Patient-Reported Diabetic Peripheral Neuropathy Symptoms

INTRODUCTION

To assess clinician response to real-time patient-reported data about diabetic peripheral neuropathy (DPN) symptoms, we analyzed DPN diagnosis and treatment patterns after administration of a 4-question symptom questionnaire in a large vertically integrated health care system.

METHODS

Retrospective cohort study to analyze data from 160,852 patients screened for DPN symptoms from April 2012 to March 2014. Electronic medical record data were used to study changes in DPN diagnosis, treatment initiation, and treatment intensification. We used logistic regression to study the association of patient characteristics with the odds of clinical response.

RESULTS

Of patients queried, 50,684 (31.5%) reported symptoms. Patients reporting DPN symptoms experienced a greater increase in new DPN diagnoses (16 percentage points; p < 0.0001) and medication use (4 percentage points; p < 0.0001) compared with those denying symptoms. Among patients reporting symptoms, women and nonwhite patients were less likely to receive a DPN diagnosis, whereas older patients were more likely to receive a DPN diagnosis. Overall, patients who were older, were Asian (hazard ratio = 0.67, 95% confidence interval = 0.63-0.77), and had lower socioeconomic status (hazard ratio = 0.89, 95% confidence interval = 0.80-0.99) were less likely to be treated. However, these racial and socioeconomic differences were not statistically significant for patients with preexisting DPN diagnoses.

CONCLUSION

Patients' real-time reports of DPN symptoms were associated with increased clinical activity. Patient- and clinician-level factors associated with the likelihood of receiving a DPN diagnosis need further study because a formal diagnosis may be associated with more equitable treatment.

Variability in the clinical diagnosis of diabetic peripheral neuropathy

AIMS

The aims of this study are to assess the variability in the prevalence of diabetic peripheral neuropathy (DPN), according to the diagnostic and clinical guidelines used.

METHODS

A cross-sectional observational study was conducted of 111 patients with diabetes mellitus. The presence/absence of DPN was determined according to 12 different criteria stipulated in various clinical guidelines (ADA 2018, IWGDF 2016, IDF 2012 and CONUEI 2018). The Cohen's kappa coefficient (κ) was performed to determine the degree of agreement for DPN diagnosis among the different criteria.

RESULTS

The recorded prevalence of DPN ranged from 13.1% (criterion ADA 2018) to 68.5% (criterion IDF 2012). The sensory parameter that was most commonly affected was the non-perception of vibration (68.5%) and the absence of Achilles reflexes (59.4%). IWGDF, based on the use of a monofilament, cotton wisp and tuning fork, was the test with more agreements, presenting good agreement with 2 criteria from ADA 2018 (k=0.845), 1b2 (k=0.817), 2 criteria from IWGDF 2016 (k=0.933), (k=0.817), 1 criteria from IDF 2012 (k=0.845) and 1 criteria from CONUEI 2018 (k=0.860), all p<0.001.

CONCLUSION

The IWGDF criterion based on the use of a monofilament, cotton wisp and tuning fork for the diagnosis presented the highest level of concordance with the other criteria (>0.8).

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.

Mechanical Noise Improves the Vibration Perception Threshold of the Foot in People With Diabetic Neuropathy

BACKGROUND

Mechanical noise may improve somatosensation at the dorsal side of the foot, but the effect at the plantar side of the foot, the side most at risk for foot ulceration, is unknown. Moreover, techniques used in research so far have several problems that limit applicability in daily practice. Piezoelectric actuators may provide mechanical noise with better clinical applicability. We assessed the effects of piezoelectric actuators generating mechanical noise on the vibration perception threshold (VPT) at the plantar side of the foot in people with diabetic neuropathy.

METHODS

Double-blind within-subjects design in a controlled laboratory setting including participants with diabetic neuropathy (N = 40; 18 male; mean age 69.6 years; mean duration of diabetes 14.1 years; mean BMI 30.5). VPT was measured at three plantar foot locations with and without mechanical noise applied via piezoelectric actuators.

RESULTS

Mechanical noise improved VPT at metatarsophalangeal joint (MTP) 1 (left 39.3V vs 43.5V; right 39.0 vs 42.6 V), MTP5 (left 37.5V vs 41.7V; right 34.5V vs 40.8V) and the heel (left 40.0V vs 44.0V; right 39.3V vs 41.0V), all P < .001.

CONCLUSIONS

Mechanical noise improves VPT at the plantar side of the foot in people with diabetic neuropathy. This is an important step for further development of insoles using mechanical noise that may have the potential to improve VPT and decrease the risk of foot ulceration.

Efficacy and safety of duloxetine and Pregabalin in Iranian patients with diabetic peripheral neuropathic pain: a double-blind, randomized clinical trial

Purpose

Diabetic peripheral neuropathic pain (DPNP) is one of the most sufferings, disabling, and dominant complications of diabetes. Duloxetine (DLX) and Pregabalin (PGB) are among first-line therapy and the most prescribed drugs for DPNP relief. The effectiveness-risk profile of drugs may differ from region to region due to variations in genetic and health situation of populations. This study aims to evaluate the efficacy and safety of DLX and PGB in a sample of Iranian population with DPNP.

Methods

A double-blind, randomized clinical trial was conducted on 180 type-2 diabetic patients with DPNP≥40 mm according to Visual Analogue Scale (VAS), with other eligibility criteria throughout twelve weeks. We divided the patients randomly into two equal groups: DLX and PGB. Each patient received ten days placebo as a washout period, then blind capsules of DLX (group 1) or PGB (group 2). We assessed the efficacy and safety of drugs by VAS and recorded the Adverse Drug Reactions (ADRs) during the study.

Results

In the DLX group, sixty-six and the PGB group, seventy-eight patients completed the study. The intensity of patients’ pain was improved by both drugs significantly (p˂0.001), but there was no significant difference between the two groups. Average daily doses of DLX and PGB were 42.5 and 235.5 mg, respectively. In the DLX group, 74% of patients and the PGB group, 37% reported ADRs. The discontinuation rates due to ADRs were 19% and 7% correspondingly.

Conclusion

We found that in Iranian patients, the mean effective doses of these drugs are different in comparison with several other studies. Surprisingly intolerance and discontinuation of DLX in our patients were attributed to mild and severe Serotonin Syndrome, which had not much occurred in other studies. Accordingly, despite the same efficacy, PGB was better tolerated than DLX in our patients. Thus we would recommend PGB for DPNP treatment in Iranian patients.

Glucose time in range and peripheral neuropathy in type 2 diabetes mellitus and chronic kidney disease

​OBJECTIVE: Compared with hemoglobin A1c (HbA1c), continuous glucose monitoring (CGM) may better capture risk of diabetes complications in patients with chronic kidney disease (CKD), including diabetic peripheral neuropathy (DPN). We hypothesized that glucose time in range (TIR), measured by CGM, is associated with DPN symptoms among participants with type 2 diabetes mellitus (type 2 DM) and moderate-to-severe CKD. ​RESEARCH DESIGN AND METHODS: We enrolled 105 people with type 2 DM treated with insulin or sulfonylurea, 81 participants with CKD (estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m²) and 24 matched control participants with eGFR ≥60 mL/min/1.73 m². Each participant wore a CGM for two 6-day periods. Calculated glycemic measures included TIR (glucose 70-180 mg/dL) and glucose management indicator (GMI). DPN symptoms were assessed using the Michigan Neuropathy Screening Instrument (MNSI) questionnaire, with a positive MNSI score defined as ≥2 symptoms. ​RESULTS: Participants with CKD had a mean age of 68 years, diabetes duration 20 years, eGFR 38 mL/min/1.73 m² and HbA1c 7.8%, 61 mmol/mol. Sixty-two participants reported ≥2 DPN symptoms, 51 (63%) with CKD and 11 (46%) controls. Less TIR and higher GMI were associated with higher risk of MNSI questionnaire score ≥2 (OR 1.25 (95% CI 1.02 to 1.52) per 10% lower TIR, and OR 1.79 (95% CI 1.05 to 3.04) per 1% higher GMI, adjusting for age, gender and race). Similar results were observed when analyses were restricted to participants with CKD. In contrast, there was no significant association of HbA1c with DPN symptoms. ​CONCLUSIONS: Symptoms of DPN were common among participants with long-standing type 2 DM and CKD. Lower TIR and higher GMI were associated with DPN symptoms.

Prevalence of Diabetic Foot Ulcer and Associated Factors among Adult Diabetic Patients on Follow-Up Clinic at Jimma Medical Center, Southwest Ethiopia, 2019: An Institutional-Based Cross-Sectional Study

BACKGROUND

Diabetic foot ulceration is a devastating complication of diabetes mellitus and is a major source of morbidity and mortality. So far, there are few published data on diabetic foot ulcers and its determinants among diabetic patients on follow-up at Jimma Medical Center. Hence, the aim of this study was to assess the prevalence of diabetic foot ulcer and its determinants among patients with diabetes mellitus at Jimma Medical Center.

METHODS

A hospital-based cross-sectional study was conducted from June 1 to August 30, 2019, and systematic random sampling technique was applied. The total number of study subjects who participated in the study was 277. Data were collected using an interview-administered structured questionnaire. Data were entered into EpiData version 3.1 and exported to SPSS version 20 software for analysis. Analysis was done using descriptive statistics and logistic regression. A variable having a p value of <0.25 in the bivariate model was subjected to multivariate analysis to avoid confounding the variable's effect. Adjusted odds ratios (AOR) were calculated at 95% confidence interval and considered significant with a p value of <0.25 in the bivariate model was subjected to multivariate analysis to avoid confounding the variable's effect. Adjusted odds ratios (AOR) were calculated at 95% confidence interval and considered significant with a.

RESULT

The mean of age of participants was 50.1 ± 14.19 years. More than three-fourths of participants (82.7%) were type 2 DM. The mean duration of diabetic patients was 6.00 ± 5.07 years. The prevalence of diabetic foot ulcer was 11.6% among study participants. According to multivariate logistic regression analysis, previous history of ulceration (AOR = 5.77; 95% CI: 2.37, 14.0) and peripheral neuropathy (AOR = 11.2; 95% CI: 2.8, 44.4) were independent predictors of diabetic foot ulcer.

CONCLUSION

The prevalence of diabetic foot ulcer was 11.6%. Previous history of ulceration and peripheral neuropathy were associated with diabetic foot ulcer. The health care providers are recommended to thoroughly give emphasis during follow-up of patients who had previous history of ulceration and peripheral neuropathy in order to decrease the occurrence of diabetic foot ulcer.

Prospective Study of Neuropathic Symptoms Preceding Clinically Diagnosed Diabetic Polyneuropathy: ADDITION-Denmark

OBJECTIVE

To evaluate whether diabetic polyneuropathy (DPN) follows the hypothesis for the course of nerve fiber damage reflected by symptoms progressing from pure small through mixed to large nerve fiber symptoms with or without symptoms of loss of function of small nerve fibers.

RESEARCH DESIGN AND METHODS

Repeated assessments of nerve fiber-specific symptoms were obtained in 518 participants of the ADDITION-Denmark study from the time of a screening-based diagnosis of type 2 diabetes using specific items of the Michigan Neuropathy Screening Instrument questionnaire. DPN was clinically assessed 13 years after inclusion. The course of symptoms reflecting dysfunction of specific nerve fibers was evaluated, and the association between symptoms and DPN was estimated using logistic regression models.

RESULTS

An overall stable, yet heterogeneous course of symptoms was seen. According to the hypothesis of symptom progression, 205 (40%) participants remained free of symptoms and 56 (11%) had stable, 114 (23%) progressing, and 132 (26%) improving symptoms. Cross-sectional estimates showed a higher risk of DPN (odds ratios between 2.1 and 4.1) for participants with mixed or large nerve fiber symptoms with or without symptoms of loss of function of small nerve fibers compared with participants without symptoms.

CONCLUSIONS

There was no evidence for a progressive development of nerve fiber damage in DPN reflected by symptoms going from pure small through mixed to large nerve fiber symptoms with or without symptoms of loss of function of small nerve fibers. Yet overall, neuropathic symptoms were prospectively associated with a higher risk of DPN.

The prevalence of peripheral neuropathy severe enough to cause a loss of protective sensation in a population-based sample of people with known and newly detected diabetes in Barbados: a cross-sectional study

AIMS

To determine the prevalence and potential risk factors for diabetic peripheral neuropathy with a loss of protective sensation in Barbados.

METHODS

A representative population sample aged > 25 years with previously diagnosed diabetes or a fasting blood glucose ≥ 7 mmol/l or HbA_1c ≥ 48 mmol/mol (6.5%) was tested by 10 g monofilament at four plantar sites per foot and a 28 Hz tuning fork and neurothesiometer at the hallux. Data were adjusted to the age structure of people with diabetes in Barbados. Multivariable logistic regression assessed associations with peripheral neuropathy with a loss of protective sensation.

RESULTS

Of 236 participants [74% response rate, 33% men, 91% black, median age 58.6 years, mean BMI 30.1 kg/m² , mean HbA_1c 54 mmol/mol (7.1%)], 51% had previously diagnosed diabetes. Foot examination demonstrated that 25.8% (95% CI 20.2 to 31.5) had at least one insensate site with monofilament testing, 14.8% (95% CI 10.2 to 19.4) had an abnormal tuning fork test and 10.9% (95% CI 6.9 to 14.9) had a vibration perception threshold > 25 V. Peripheral neuropathy with a loss of protective sensation prevalence was 28.5% (95% CI 22.7 to 34.4) as indicated by monofilament with ≥ 1 insensate site and/or vibration perception threshold > 25 V. With previously diagnosed diabetes the prevalence was 36.4% (95% CI 27.7 to 45.2) with 98.4% of cases identified by monofilament testing. Increasing age, previously diagnosed diabetes, male sex and abdominal obesity were independently associated with peripheral neuropathy with a loss of protective sensation.

CONCLUSIONS

Over a third of people with previously diagnosed diabetes had evidence of peripheral neuropathy with a loss of protective sensation. Monofilament testing alone may be adequate to rule out peripheral neuropathy with a loss of protective sensation. Monofilament and neurothesiometer stimuli are reproducible but dependent on participant response.

Diabetic peripheral neuropathy: advances in diagnosis and strategies for screening and early intervention

Diabetic peripheral neuropathy (DPN) is a common complication of both type 1 and 2 diabetes. It is a leading cause of lower-limb amputation and disabling neuropathic pain. Amputations in patients with diabetes have a devastating effect on quality of life and are associated with an alarmingly low life expectancy (on average only 2 years from the amputation). Amputation also places a substantial financial burden on health-care systems and society in general. With the introduction of national diabetes eye screening programmes, the prevalence of blindness in working-age adults is falling. This is not the case, however, with diabetes related amputations. In this Review, we appraise innovative point-of-care devices that enable the early diagnosis of DPN and assess the evidence for early risk factor-based management strategies to reduce the incidence and slow the progression of DPN. We also propose a framework for screening and early multifactorial interventions as the best prospect for preventing or halting DPN and its devastating sequelae.

Sex differences in neuropathy & neuropathic pain: A brief report from the Phase 2 Canadian Study of Longevity in Type 1 Diabetes

To evaluate previous results from a questionnaire-based study, we studied objective neuropathy measures to determine sex differences in the prevalence of neuropathy and neuropathic pain in longstanding type 1 diabetes. Despite better neuropathy measures in females compared to males, we confirmed a trend towards higher neuropathic pain in females.

Microvascular complications burden (nephropathy, retinopathy and peripheral polyneuropathy) affects risk of major vascular events and all-cause mortality in type 1 diabetes: a 10-year follow-up study

BACKGROUND

Microvascular complications (MC) have been claimed to increase the risk for cardiovascular disease in diabetic subjects. However, the effect of MC burden on the risk of major vascular outcomes and all-cause mortality in type 1 diabetes is still poorly explored. We evaluated the relationship between microvascular complications burden and incidence of major cardiovascular events and all-cause mortality in subjects with type 1 diabetes.

METHODS

We recruited 774 participants with type 1 diabetes in a single-center observational study over a follow-up of 10.8 ± 2.5 years. Hazard ratios (HR) for cardiovascular outcomes and all-cause death associated with microvascular complications were determined by unadjusted and adjusted Cox regression analysis.

RESULTS

Out of 774 individuals, 54.9% had no-MC, 32.3% 1 MC, 9.7% 2 MC and 3.1% 3 MC. A total of 54 deaths (7.0%) occurred. Death rate increased from no-MC 2.1% (Ref) to 1 MC 7.2% (HR 3.54 [95% CI 1.59-7.87]), 2 MC 14.7% (HR 6.41 [95% CI 2.65-15.49]) and 3 MC 66.7% (HR 41.73 [95% CI 18.42-94.57], p < 0.0001). After adjustments, HRs were: 1 MC 2.05 (95% CI 0.88-4.76), 2 MC 1.98 (95% CI 0.75-5.21), 3 MC 7.02 (95% CI 2.44-20.20, p = 0.002). Forty-nine subjects (6.7%) had at least one cardiovascular event, and cumulative incidence went from no-MC 2.2% (Ref) to 1 MC 5.0%; (HR 2.27 [95% CI 0.96-5.38]), 2 MC 26.8% (HR 12.88 [95% CI 5.82-28.50]) and 3 MC 40.9% (HR 29.34 [95% CI 11.59-74.25], p < 0.0001). Upon adjustments, HRs were: 1 MC 1.59 (95% CI 0.65-3.88), 2 MC 4.33 (95% CI 1.75-10.74), 3 MC 9.31 (95% CI 3.18-27.25, p < 0.0001). Thirty-five individuals (4.8%) had at least one coronary event, which cumulative incidence increased with MC burden (p < 0.0001).

CONCLUSIONS

In type 1 diabetes, microvascular complications burden increases in an independent dose-dependent manner the risk of major cardiovascular outcomes and all-cause mortality. The presence and number of microvascular complications should be considered in stratifying overall cardiovascular risk in type 1 diabetes.

Baseline Characteristics of Randomized Participants in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE)

OBJECTIVE

GRADE (Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study) is a 36-center unmasked, parallel treatment group, randomized controlled trial evaluating four diabetes medications added to metformin in people with type 2 diabetes (T2DM). We report baseline characteristics and compare GRADE participants to a National Health and Nutrition Examination Survey (NHANES) cohort.

RESEARCH DESIGN AND METHODS

Participants were age ≥30 years at the time of diagnosis, with duration of T2DM <10 years, HbA1c 6.8-8.5% (51-69 mmol/mol), prescribed metformin monotherapy, and randomized to glimepiride, sitagliptin, liraglutide, or insulin glargine.

RESULTS

At baseline, GRADE's 5,047 randomized participants were 57.2 ± 10.0 years of age, 63.6% male, with racial/ethnic breakdown of 65.7% white, 19.8% African American, 3.6% Asian, 2.7% Native American, 7.6% other or unknown, and 18.4% Hispanic/Latino. Duration of diabetes was 4.2 ± 2.8 years, with mean HbA1c of 7.5 ± 0.5% (58 ± 5.3 mmol/mol), BMI of 34.3 ± 6.8 kg/m2, and metformin dose of 1,944 ± 204 mg/day. Among the cohort, 67% reported a history of hypertension, 72% a history of hyperlipidemia, and 6.5% a history of heart attack or stroke. Applying GRADE inclusion criteria to NHANES indicates enrollment of a representative cohort with T2DM on metformin monotherapy (NHANES cohort average age, 57.9 years; mean HbA1c, 7.4% [57 mmol/mol]; BMI, 33.2 kg/m2; duration, 4.2 ± 2.5 years; and 7.2% with a history of cardiovascular disease).

CONCLUSIONS

The GRADE cohort represents patients with T2DM treated with metformin requiring a second diabetes medication. GRADE will inform decisions about the clinical effectiveness of the addition of four classes of diabetes medications to metformin.

Painful and non-painful diabetic polyneuropathy: Clinical characteristics and diagnostic issues

Diabetic neuropathy (DN) is a common complication of diabetes and can be either painful or non-painful. It is challenging to diagnose this complication, as no biomarker or clear consensus on the clinical definition of either painful or non-painful DN exists. Hence, a hierarchical classification has been developed categorizing the probability of the diagnosis into: possible, probable or definite, based on the clinical presentation of symptoms and signs. Pain is a warning signal of tissue damage, and non-painful DN therefore represents a clinical and diagnostic challenge because it often goes unnoticed until irreversible nerve damage has occurred. Simple clinical tests seem to be the best for evaluation of DN in the general care for diabetes. Screening programs at regular intervals might be the most optimal strategy for early detection and interventions to possibly prevent further neuronal damage and to lower the economic burden of this complication.

The association between perceived discrimination in midlife and peripheral neuropathy in a population-based cohort of women: the Study of Women's Health Across the Nation

PURPOSE

Peripheral neuropathy (PN) is a highly prevalent condition with serious sequelae. Many studies of the condition have been restricted to populations with diabetes, limiting evidence of potential contributing risk factors including salient psychosocial risk factors such as discrimination.

METHODS

The longitudinal Study of Women's Health Across the Nation was used to assess the relationship between perceived discrimination and prevalent PN in 1718 ethnically diverse midlife women. We used multivariable logistic regression to determine the association between perceived discrimination (Detroit Area Study Everyday Discrimination Scale) and PN (symptom questionnaire and monofilament testing) and conducted an assessment of the mediating effects of body mass index (BMI).

RESULTS

The prevalence of PN was 26.1% in the total sample and 40.9% among women with diabetes. Women who reported perceived discrimination had 29% higher odds of PN compared with women who did not report perceived discrimination (95% confidence interval, 1.01-1.66). Approximately 30% of the total effect of discrimination on PN was mediated indirectly by BMI.

CONCLUSIONS

More research is needed to determine the contributing factors to nondiabetic PN. Our findings reaffirm the impact of financial strain, BMI, and diabetes as significant correlates of PN and highlight discrimination as an important risk factor.

Cardiac autonomic neuropathy in nonobese young adults with type 1 diabetes

PURPOSE

The aim of this study was to evaluate the prevalence and risk factors for cardiac autonomic neuropathy (CAN) in nonobese nonobese young type 1 diabetes mellitus (T1DM) patients without micro- or macrovascular complications.

METHODS

CAN was assessed in 95 patients with T1DM, aged 18-29 years, using standard cardiovascular reflex tests - heart rate response to deep breathing, standing, and the Valsalva maneuver and blood pressure response to standing. Furthermore, power spectral analyses of overall heart rate variability (HRV), standard deviation of NN intervals (SDNN), and total power (TP) were tested with DiCAN. CAN was defined as abnormal results for at least 1 of the 4 cardiovascular reflex tests.

RESULTS

The prevalence of CAN was 12.6%. The frequency of one and 2 abnormal reflex tests was 10.5% and 2.1%, respectively. No significant differences were observed in age, sex, mean hemoglobin A1c (HbA1c) level, and duration of diabetes with respect to presence of CAN. Patients with CAN exhibited lower overall HRV parameters (SDNN and TP) compared with those without CAN even though there was no statistical significance. In multivariable analyses, higher mean HbA1c level was significantly associated with lower overall HRV (β=-44.42, P=0.002 for SDNN and β=-2.82, P&lt;0.001 for TP).

CONCLUSION

CAN can be detected in 12.6% of young adult T1DM patients even without other micro- or macrovascular complications. Glycemic control is the main determinant to maintain overall HRV and prevent CAN.

Association between deterioration in muscle strength and peripheral neuropathy in people with diabetes

AIMS

Diabetic peripheral neuropathy (DPN) is a major risk factor for sarcopenia or frailty in older patients with diabetes. In this study, we investigated the association between DPN and muscle strength in type 2 diabetes.

METHODS

DPN was assessed using the Michigan Neuropathy Screening Instrument Questionnaire (MNSI-Q) and Physical Examination (MNSI-PE) in 230 subjects with type 2 diabetes. Handgrip strength (HGS) was measured using an electronic grip strength dynamometer.

RESULTS

The prevalence of DPN was 26.4% in men and 34.7% in women. HGS was significantly lower in men with DPN compared with men without DPN (27.0 ± 9.4 vs. 29.7 ± 8.4 kg, p = 0.036). This effect was not seen in women. In men, multivariate regression analysis showed that HGS was negatively associated with the MNSI-Q (β = -1.200, p = 0.003) and MNSI-PE scores (β = -0.937, p = 0.046) and resulted in an abnormal 10-gram monofilament test score (β = -10.895, p < 0.001). However, HGS was not significantly associated with neuropathy in women.

CONCLUSIONS

Muscle strength was lower in men with DPN than in those without DPN. Assessment of muscle function may have clinical implications in the prevention of sarcopenia and frailty in men with DPN.

A Genetic Locus on Chromosome 2q24 Predicting Peripheral Neuropathy Risk in Type 2 Diabetes: Results From the ACCORD and BARI 2D Studies

Genetic factors have been postulated to be involved in the etiology of diabetic peripheral neuropathy (DPN), but their identity remains mostly unknown. The aim of this study was to conduct a systematic search for genetic variants influencing DPN risk using two well-characterized cohorts. A genome-wide association study (GWAS) testing 6.8 million single nucleotide polymorphisms was conducted among participants of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial. Included were 4,384 white case patients with type 2 diabetes (T2D) and prevalent or incident DPN (defined as a Michigan Neuropathy Screening Instrument clinical examination score >2.0) and 784 white control subjects with T2D and no evidence of DPN at baseline or during follow-up. Replication of significant loci was sought among white subjects with T2D (791 DPN-positive case subjects and 158 DPN-negative control subjects) from the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D) trial. Association between significant variants and gene expression in peripheral nerves was evaluated in the Genotype-Tissue Expression (GTEx) database. A cluster of 28 SNPs on chromosome 2q24 reached GWAS significance (P < 5 × 10-8) in ACCORD. The minor allele of the lead SNP (rs13417783, minor allele frequency = 0.14) decreased DPN odds by 36% (odds ratio [OR] 0.64, 95% CI 0.55-0.74, P = 1.9 × 10-9). This effect was not influenced by ACCORD treatment assignments (P for interaction = 0.6) or mediated by an association with known DPN risk factors. This locus was successfully validated in BARI 2D (OR 0.57, 95% CI 0.42-0.80, P = 9 × 10-4; summary P = 7.9 × 10-12). In GTEx, the minor, protective allele at this locus was associated with higher tibial nerve expression of an adjacent gene (SCN2A) coding for human voltage-gated sodium channel NaV1.2 (P = 9 × 10-4). To conclude, we have identified and successfully validated a previously unknown locus with a powerful protective effect on the development of DPN in T2D. These results may provide novel insights into DPN pathogenesis and point to a potential target for novel interventions.

Reconfirmation of newly discovered risk factors of diabetic peripheral neuropathy in patients with type 2 diabetes: A case-control study

AIMS

The aim of the present study was to investigate the major determinants of diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes (T2D), considering the traditional and newly discovered risk factors, including hypoglycaemia and glycemic variability.

METHODS

This retrospective case-control study was conducted in a tertiary care hospital in Taiwan. A total of 2,837 patients with T2D were recruited, medical history and biochemical data were obtained, and patients were screened for DPN using the Michigan Neuropathy Screening Instrument (MNSI). DPN was defined as an MNSI exam score > 2. A stepwise selection of variables was used based on the Akaike Information Criterion (AIC) and the Schwarz Criterion (SC). Multivariate analysis was performed using the identified variables obtained from the stepwise selection.

RESULTS

Among the recruited patients, 604 (21.3%) were found to have DPN. 275 patients with DPN were selected because of longer follow up period before enrollment and complete data of glycemic parameters, and paired with 351 patients with T2D without DPN and matched for age, gender, and diabetes duration. The results of the stepwise selection showed that the presence of moderately and severely increased albuminuria yielded the lowest values of AIC and SC, which indicate the best predictive performance. Multivariate analysis demonstrated that moderately and severely increased albuminuria and greater long-term glycemic variability significantly increased the risk of DPN, with a corresponding odds ratio of 1.85 and 1.61 (95%confidence intervals of 1.25-2.73and1.02-2.55, respectively), after adjusted for hypoglycaemia and types of diabetes treatment.

CONCLUSIONS

Albuminuria is a potent predictor of DPN, and greater long-term glycemic variabilityis clearly associated with DPN in adults with T2D. These findings indicate that, in addition to achieve average blood glucose control, screening for albuminuria and reducing blood glucose fluctuations might be useful for improving diabetic microvascular complications.

Diagnostic value of symptoms in chronic polyneuropathy: The Erasmus Polyneuropathy Symptom Score

In this study, we evaluated the diagnostic value of symptoms of chronic polyneuropathy and to construct and validate a simple questionnaire that can help diagnose chronic polyneuropathy. In a multi-step procedure, we initially compiled a 12-item questionnaire concerning polyneuropathy symptoms. The questionnaire was completed by 117 polyneuropathy patients and 188 controls (headache, transient ischemic attack, multiple sclerosis). First, we calculated sensitivity, specificity and likelihood ratios of each symptom. Next, we used multi-variable logistic regression to create a model that could discriminate patients from controls, using only the most informative symptoms and their frequency of occurrence. Based on the regression coefficients, we developed a simple scoring system (Erasmus Polyneuropathy Symptom Score, E-PSS), which was externally validated in 140 cases with chronic idiopathic axonal polyneuropathy and 96 controls without polyneuropathy. We assessed performance with discrimination (area under the curve, AUC) and calibration analyses. Numb and tingling feet were most frequently reported by polyneuropathy patients and had the highest sensitivity. Walking on cotton wool and allodynia had the highest specificity. Logistic regression yielded a model that contained these four symptoms, complemented with balance problems and tingling hands. Based on this analysis, the E-PSS was created, ranging from 0 to 14. The E-PSS had a good performance (AUC = 0.92) in the derivation set and proved to be valid in the external population (AUC = 0.95). In conclusion, the Erasmus Polyneuropathy Symptom Score (E-PSS) is a simple, validated six-item score that takes the presence and frequency of six different symptoms into account and it may be a helpful tool to screen individuals for the presence of chronic polyneuropathy.

An ultrafast system for signaling mechanical pain in human skin

The canonical view is that touch is signaled by fast-conducting, thickly myelinated afferents, whereas pain is signaled by slow-conducting, thinly myelinated ("fast" pain) or unmyelinated ("slow" pain) afferents. While other mammals have thickly myelinated afferents signaling pain (ultrafast nociceptors), these have not been demonstrated in humans. Here, we performed single-unit axonal recordings (microneurography) from cutaneous mechanoreceptive afferents in healthy participants. We identified A-fiber high-threshold mechanoreceptors (A-HTMRs) that were insensitive to gentle touch, encoded noxious skin indentations, and displayed conduction velocities similar to A-fiber low-threshold mechanoreceptors. Intraneural electrical stimulation of single ultrafast A-HTMRs evoked painful percepts. Testing in patients with selective deafferentation revealed impaired pain judgments to graded mechanical stimuli only when thickly myelinated fibers were absent. This function was preserved in patients with a loss-of-function mutation in mechanotransduction channel PIEZO2. These findings demonstrate that human mechanical pain does not require PIEZO2 and can be signaled by fast-conducting, thickly myelinated afferents.

Gait Abnormalities and the Risk of Falls in CKD

BACKGROUND AND OBJECTIVES

Older adults with CKD are at high risk of falls and disability. It is not known whether gait abnormalities contribute to this risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Quantitative and clinical gait assessments were performed in 330 nondisabled community-dwelling adults aged ≥65 years. CKD was defined as an eGFR <60 ml/min per 1.73 m². Cox proportional hazards models were created to examine fall risk.

RESULTS

A total of 41% (n=134) of participants had CKD. In addition to slower gait speed, participants with CKD had gait cycle abnormalities including shorter stride length and greater time in the stance and double-support phases. Among people with CKD, lower eGFR was independently associated with the severity of gait cycle abnormalities (per 10 ml/min per 1.73 m² lower eGFR: 3.6 cm [95% confidence interval (95% CI), 1.4 to 5.8] shorter stride length; 0.7% [95% CI, 0.3 to 1.0] less time in swing phase; 1.1% [95% CI, 0.5 to 1.7] greater time in double-support phase); these abnormalities mediated the association of lower eGFR with slower gait speed. On clinical gait exam, consistent with the quantitative abnormalities, short steps and marked swaying or loss of balance were more common among participants with CKD, yet most had no identifiable gait phenotype. A gait phenotype defined by any of these abnormal signs was associated with higher risk of falls among participants with CKD: compared with people without CKD and without the gait phenotype, the adjusted hazard ratio was 1.72 (95% CI, 1.06 to 2.81) for those with CKD and the phenotype; in comparison, the adjusted hazard ratio was 0.71 (95% CI, 0.40 to 1.25) for people with CKD but without the phenotype (P value for interaction of CKD status and gait phenotype =0.01).

CONCLUSIONS

CKD in older adults is associated with quantitative gait abnormalities, which clinically manifest in a gait phenotype that is associated with fall risk.

Diabetic neuropathy

The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.

Diabetic neuropathy

The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.

Type 1 diabetes onset at young age is associated with compromised bone quality

Women with type 1 diabetes (T1D) are at increased risk for fracture. We studied the association of T1D and young age at T1D onset (T1D onset before 20 years) on bone structural quality. 24 postmenopausal women with T1D (mean age 60.9 years, mean T1D duration 41.7 years) and 22 age, sex- and body mass index (BMI)-matched controls underwent dual X-ray absorptiometry (DXA) measured areal bone mineral density (aBMD) at the lumbar spine, hip and distal radius. Bone mass, geometry and estimated bone strength were assessed at distal and shaft of non-dominant radius and tibia using peripheral quantitative computed tomography (pQCT). Postmenopausal women with T1D had lower trabecular volumetric bone mineral density (vBMD) (LSM ± SEM; 166.1 ± 8.2 vs 195.9 ± 8.3 mg/cm3, p = 0.02) and compressive bone strength (24.6 ± 1.8 vs 30.1 ± 1.9 mg2/mm4, p = 0.04) at the distal radius compared to controls adjusting for age, BMI and radius length. At the distal radius, patients with young onset T1D had lower total vBMD (258.7 ± 19.7 vs 350.8 ± 26.1 mg/cm3, p = 0.02) and trabecular vBMD (141.4 ± 11.6 vs 213.6 ± 15.4 mg/cm3, p = 0.003) compared to adult onset T1D patients adjusting for age, BMI and the radius length. At the tibial shaft, young onset T1D patients had larger endosteal circumference (39.1 ± 1.2 vs 32.1 ± 1.6 mm, p = 0.005) with similar periosteal circumference (67.1 ± 0.9 vs 65.1 ± 1.2 mm, p = 0.2) resulting in reduced cortical thickness (4.4 ± 0.1 vs 5.2 ± 0.1 mm, p = 0.004) compared to adult onset T1D patients adjusting for age, BMI and the tibia length. There was no difference in the lumbar spine, femoral neck, total hip and distal radius DXA-measured aBMD between subjects with T1D and controls. T1D is associated with lower trabecular vBMD at the distal radius. T1D onset before age 20 is associated with cortical bone size deficits at the tibial shaft.

Factors Affecting Cardiovascular Risk in Children, Adolescents, and Young Adults with Type 1 Diabetes

Cardiovascular risk and obesity are becoming major health issues among individuals with type 1 diabetes (T1D). The aim of this study was to evaluate cardiovascular risk factors and obesity in youth with T1D in Lithuania. Methods. 883 patients under 25 years of age with T1D for at least 6 months were investigated. Anthropometric parameters, blood pressure, and microvascular complications were evaluated, and the lipid profile and HbA1c were determined for all patients. Results. Study subjects' mean HbA1c was 8.5 ± 2%; 19.5% were overweight and 3.6% obese. Hypertension and dyslipidemia were diagnosed in 29.8% and 62.6% of participants, respectively. HbA1c concentration was directly related to levels of total cholesterol (r = 0.274, p < 0.001), LDL (r = 0.271, p < 0.001), and triglycerides (r = 0.407, p < 0.001) and inversely associated with levels of HDL (r = 0.117, p = 0.001). Prevalence of dyslipidemia increased with duration of diabetes (p < 0.05). Hypertension was more prevalent in overweight and obese compared to normal-weight patients (40.6 and 65.6 vs. 25.6%, respectively, p < 0.001). Frequency of microvascular complications was higher among patients with dyslipidemia (27.2 vs. 18.8%, p = 0.005) and among those with hypertension (25.9 vs. 23.2%, p < 0.001). Conclusion. The frequency of cardiovascular risk factors is high in youth with T1D and associated with diabetes duration, obesity, and metabolic control.

Use of graded Semmes Weinstein monofilament testing for ascertaining peripheral neuropathy in people with and without diabetes

AIMS

To assess peripheral neuropathy (PN) using graded Semmes Weinstein monofilaments (SWMs) and determine factors associated with PN among adult volunteers with and without diabetes.

METHODS

Adult volunteers were assessed for distal sensory PN using three graded SWMs. Four PN levels were defined: 0 (no PN; felt all three filaments), 1 (subclinical PN; insensate to 1-g filament), 2 (insensate to 10-g), or 3 (insensate to 75-g). Levels 2-3 were considered clinical PN. Associations with PN were determined using ordinal logistic regression.

RESULTS

In 1564 subjects (median age 41.9 years, 50.1% women), PN was subclinical or worse in 68.9% and clinical in 11.2%. Age-sex-race-adjusted prevalence of clinical PN was greater in people with diabetes (15.3%) than without (6.1%; P < 0.001). Associated factors included older age, male sex, greater BMI, greater heart rate, lower mean arterial pressure, and family history of diabetes or cardiovascular diseases. Higher PN levels associated with worse albuminuria and retinopathy. Only older age and male sex associated with PN both in people with and without diabetes.

CONCLUSIONS

PN is common in our sample, notably in those without diabetes, although diabetes greatly increases its risk. Using graded SWMs may have a prognostic value as it permits the identification of subclinical PN.

Predicting ulcer-free survival using the discriminative value of screening test locations

BACKGROUND

Current guidelines recommend screening the feet of diabetic subjects with a 10-g monofilament or tuning fork. We investigated which tests and locations on the feet have the best predictive value regarding 1-year ulcer-free survival in diabetic subjects participating in the prospective Rotterdam Diabetic Foot Study.

METHODS

Decision tree analysis was used to predict ulcer-free survival based on responses from individual test locations (monofilaments on 10 sites, vibration sense was tested on both halluces and medial malleoli). Separate trees for patients with and without a history of diabetic foot ulcer (DFU) were developed.

RESULTS

Four hundred sixteen subjects (mean [SD] age, 61.8 years [12.4]; range, 21.6-90.2) were measured, of whom 24 developed new DFUs. Three tests exhibited discriminative and predictive properties: testing vibration sense on the medial malleolus and monofilament testing on heel and hallux. The decision tree to predict ulcer-free survival in patients with a history of DFU yielded a sensitivity of 87.0%, which was 99.6% for the tree of patients without a history of DFU.

CONCLUSION

The findings of this study aids medical decision making by discriminating between high- and low-risk patients of developing DFU using selective testing on sites with predictive properties.

An update on the diagnosis and treatment of diabetic somatic and autonomic neuropathy

Diabetic peripheral neuropathy (DPN) is the most common chronic complication of diabetes. It poses a significant challenge for clinicians as it is often diagnosed late when patients present with advanced consequences such as foot ulceration. Autonomic neuropathy (AN) is also a frequent and under-diagnosed complication unless it is overtly symptomatic. Both somatic and autonomic neuropathy are associated with increased mortality. Multiple clinical trials have failed because of limited efficacy in advanced disease, inadequate trial duration, lack of effective surrogate end-points and a lack of deterioration in the placebo arm in clinical trials of DPN. Multifactorial risk factor reduction, targeting glycaemia, blood pressure and lipids can reduce the progression of DPN and AN. Treatment of painful DPN reduces painful symptoms by about 50% at best, but there is limited efficacy with any single agent. This reflects the complex aetiology of painful DPN and argues for improved clinical phenotyping with the use of targeted therapy, taking into account co-morbid conditions such as anxiety, depression and sleep disturbance.

General and Abdominal Obesity and Incident Distal Sensorimotor Polyneuropathy: Insights Into Inflammatory Biomarkers as Potential Mediators in the KORA F4/FF4 Cohort

OBJECTIVE

To investigate the associations between different anthropometric measurements and development of distal sensorimotor polyneuropathy (DSPN) considering interaction effects with prediabetes/diabetes and to evaluate subclinical inflammation as a potential mediator.

RESEARCH DESIGN AND METHODS

This study was conducted among 513 participants from the Cooperative Health Research in the Region of Augsburg (KORA) F4/FF4 cohort (aged 62-81 years). Anthropometry was measured at baseline. Incident DSPN was defined by neuropathic impairments using the Michigan Neuropathy Screening Instrument at baseline and follow-up. Associations between anthropometric measurements and DSPN were estimated by multivariable logistic regression. Potential differences by diabetes status were assessed using interaction terms. Mediation analysis was conducted to determine the mediation effect of subclinical inflammation in these associations.

RESULTS

After a mean follow-up of 6.5 years, 127 cases with incident DSPN were detected. Both general and abdominal obesity were associated with development of DSPN. The odds ratios (95% CI) of DSPN were 3.06 (1.57; 5.97) for overweight, 3.47 (1.72; 7.00) for obesity (reference: normal BMI), and 1.22 (1.07; 1.38) for 5-cm differences in waist circumference, respectively. Interaction analyses did not indicate any differences by diabetes status. Two chemokines (C-C motif chemokine ligand 7 [CCL7] and C-X-C motif chemokine ligand 10 [CXCL10]) and one neuron-specific marker (Delta/Notch-like epidermal growth factor-related receptor [DNER]) were identified as potential mediators, which explained a proportion of the total effect up to 11% per biomarker.

CONCLUSIONS

General and abdominal obesity were associated with incident DSPN among individuals with and without diabetes, and this association was partly mediated by inflammatory markers. However, further mechanisms and biomarkers should be investigated as additional mediators to explain the remainder of this association.

Retinopathy and RAAS Activation: Results From the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

The importance of renin-angiotensin-aldosterone system (RAAS) activation in retinopathy for long-standing diabetes is not well understood. We determined retinopathy stage and evaluated associations with other vascular complications before and after physiological RAAS activation in adults with long-standing (≥50 years duration) type 1 diabetes.

RESEARCH DESIGN AND METHODS

Participants underwent retinal examination by digital funduscopic photography and optical coherence tomography and were classified as having nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), or no diabetic retinopathy (NDR) with or without diabetic macular edema (DME). Neuropathy was measured by clinical neuropathy examination scores, electrophysiologically, and by corneal confocal microscopy. Renal function was measured by inulin and para-aminohippurate clearance methods. Arterial stiffness was measured by applanation tonometry. Renal function, blood pressure, and arterial stiffness were measured before and after RAAS activation with angiotensin II (ANGII). Associations were determined using linear regression.

RESULTS

Twelve (16%) of the 75 participants had NDR, 24 (32%) had NPDR, and 39 (52%) had PDR. A low overall prevalence of DME (4%) was observed. Those with PDR had worse nerve function and reduced corneal nerve density, were more likely to have macrovascular disease, and had increased arterial stiffness in response to ANGII compared with those with NPDR or NDR. Prevalence of kidney disease or renal hemodynamic function did not differ by retinopathy status.

CONCLUSIONS

PDR was associated with neuropathy severity and cardiovascular and peripheral vascular disease. In those with PDR, RAAS activation may be linked to vascular stiffening, an effect that persists in long-standing type 1 diabetes.

Trigeminal nociceptive function and oral somatosensory functional and structural assessment in patients with diabetic peripheral neuropathy

This case-control study primarily compared the trigeminal nociceptive function, the intraoral somatosensory profile and possible structural nerve changes between diabetic peripheral neuropathy (DPN, n = 12) patients and healthy participants (n = 12). The nociceptive blink reflex (nBR) was recorded applying an electrical stimulation over the entry zone of the right supraorbital (V1R), infraorbital (V2R) and mental (V3R) and left infraorbital (V2L) nerves. The outcomes were: individual electrical sensory (I₀) and pain thresholds (I_P); root mean square (RMS), area-under-the-curve (AUC) and onset latencies of R2 component of the nBR. Furthermore, a standardized full battery of quantitative sensory testing (QST) and intraepidermal nerve fibre density (IENFD) or  nerve fibre length density (NFLD) assessment were performed, respectively, on the distal leg and oral mucosa. As expected, all patients had altered somatosensory sensitivity and lower IENFD in the lower limb. DPN patients presented higher I₀, I_P, RMS and AUC values (p < 0.050), lower warm detection thresholds (WDT) (p = 0.004), higher occurrence of paradoxical heat sensation (PHS) (p = 0.040), and a lower intraoral NFLD (p = 0.048) than the healthy participants. In addition, the presence of any abnormal intraoral somatosensory finding was more frequent in the DPN patients when compared to the reference group (p = 0.013). Early signs of trigeminal nociceptive facilitation, intraoral somatosensory abnormalities and loss of intraoral neuronal tissue can be detected in DPN patients.

Translation and Psychometric Properties of the Arabic Version of Michigan Neuropathy Screening Instrument in Type 2 Diabetes

OBJECTIVE

To translate the patient questionnaire section of the Michigan Neuropathy Screening Instrument (MNSI) into Arabic, examine the reliability of the translated version, and provide descriptive data on a sample of patients with type 2 diabetes.

METHODS

Researchers used the translation-back translation method to obtain MNSI Arabic. The test was then applied on 76 patients with type 2 diabetes. A subgroup of 25 patients answered MNSI Arabic twice to examine reliability.

RESULTS

The intraclass correlation coefficient was 0.87, revealing good reliability of MNSI Arabic. The most common symptoms patients complained of were numbness (62%), prickling feelings (57%), burning pain (47%), and pain with walking (46%).

CONCLUSION

Similar to the original MNSI version, our study demonstrates that the Arabic version of the MNSI questionnaire is a reliable tool for screening the symptomatic neuropathy status in patients with type 2 diabetes. Availability of this tool in Arabic will provide valuable and easy-to-obtain screening information regarding diabetic peripheral neuropathy that may help delay its complications by promoting early management.

Management of diabetes complications in youth

Type 1 and type 2 diabetes are increasing in prevalence and diabetes complications are common. Diabetes complications are rarely studied in youth, despite the potential onset in childhood. Microvascular complications of diabetes include retinopathy, diabetic kidney disease or nephropathy, and neuropathy that may be somatic or autonomic. Macrovascular disease is the leading cause of death in patients with type 1 diabetes. Strict glycaemic control will reduce microvascular and macrovascular complications; however, they may still manifest in youth. This article discusses the diagnosis and treatment of complications that arise from type 1 and type 2 diabetes mellitus in youth. Screening for complications is paramount as early intervention improves outcome. Screening should commence from 11 years of age depending on the duration of type 1 diabetes or at diagnosis for patients with type 2 diabetes. Diabetic retinopathy may require invasive treatment such as laser therapy or intravitreal antivascular endothelial growth factor therapy to prevent future blindness. Hypertension and albuminuria may herald diabetic nephropathy and require management with angiotensin converting enzyme (ACE) inhibition. In addition to hypertension, dyslipidaemia must be treated to reduce macrovascular complications. Interventional trials aimed at examining the treatment of diabetes complications in youth are few. Statins, ACE inhibitors and metformin have been successfully trialled in adolescents with type 1 diabetes with positive effects on lipid profile, microalbuminuria and measures of vascular health. Although relatively rare, complications do occur in youth and further research into effective treatment for diabetes complications, particularly therapeutics in children in addition to prevention strategies is required.

Observational clinical and nerve conduction study on effects of a nutraceutical combination on painful diabetic distal symmetric sensory-motor neuropathy in patients with diabetes type 1 and type 2

BACKGROUND

Painful distal symmetric polyneuropathy (pDSPN) is one of the most common and invalidating complications of diabetes mellitus, both of type 1 and type 2. Mechanisms responsible for the occurrence of the pDSPN are multifactorial and involve metabolic pathways regulating inflammation, microvessel circulation, axonal degeneration and so on. Several therapeutic approaches have been proposed to treat pain and each of them showed positive effects associated to drug-related side effects.

METHODS

Twenty-five consecutive patients with diagnosis of diabetes mellitus and pDSPN and tried to manage pain with a dietary supplement composed of a mixture of natural extracts (β-caryophyllene, myrrh, carnosic acid) and PEA. This is a nutraceutical with potential multiple effects on metabolic, pain and vascular compartments, a profile considered useful in pDSPN. Patients were enrolled and polyneuropathy evaluated by means of nerve conduction study. Pain was assessed using VAS score scale and MNSI. Each patient was evaluated at T0 (time of enrollment) and at T1 (after 16 weeks of treatment).

RESULTS

Supplement administration was well tolerated and induced unexpectedly significant amelioration of polyneuropathy with increase amplitude and reduction of pain. No side effects were reported.

CONCLUSIONS

This fixed combination could well be considered as a potential nutraceutical option to manage pDSPN in diabetic patients.