Prognostic value of longitudinal HbA1c variability in predicting the development of diabetic sensorimotor polyneuropathy among patients with type 2 diabetes mellitus: A prospective cohort observational study.

AIMS/INTRODUCTION: This prospective cohort study aims to identify the optimal measure of glycated hemoglobin (HbA1c) variability and to explore its relationship with the development of new diabetic sensorimotor polyneuropathy (DSPN) in individuals with type 2 diabetes mellitus, building upon previous cross-sectional studies that highlighted a significant association between HbA1c visit-to-visit variability and DSPN. MATERIALS AND METHODS: In a prospective study, 321 participants diagnosed with type 2 diabetes mellitus underwent comprehensive clinical assessments, neurophysiologic studies, and laboratory evaluations at enrollment and follow-up. Various indices, including HbA1c standard deviation (HbA1c SD), coefficient of variation (HbA1c CV), HbA1c change score (HbA1c HVS), and average real variability (HbA1c ARV), were employed to calculate the visit-to-visit variability HbA1c based on 3 month intervals. The investigation focused on examining the associations between these indices and the development of new DSPN. RESULTS: The average follow-up duration was 16.9 ± 6.9 months. The Cox proportional hazards model identified age (P = 0.001), diabetes duration (P = 0.024), and HbA1C ARV (P = 0.031) as the sole factors associated with the development of new DSPN. Furthermore, the cumulative risk of developing DSPN over 1 year demonstrated a significant association with HbA1C ARV (P = 0.03, log-rank test). CONCLUSIONS: Apart from age and diabetes duration, HbA1c variability emerged as a robust predictor for the occurrence of new DSPN. Among the various measures of HbA1c variability evaluated, HbA1c ARV demonstrated the highest potential as a reliable indicator for anticipating the onset of new DSPN.

Nerve Decompression in the Lower Leg Results in an Improvement in Symptoms in Patients With Both Diabetic and Idiopathic Polyneuropathy.

BACKGROUND: Patients suffering from polyneuropathy often complain of pain, tingling, and numbness sensations, as well as an increased risk of falling with the corresponding subsequent complications. If symptoms persist after conservative treatment options have been exhausted, nerve decompression in the lower extremity, as described by Dellon, can bring about an improvement in symptoms in many patients. Dellon originally reported that this surgery led to very successful outcomes in patients with diabetic polyneuropathy. In this study, we compare our postsurgical results in patients with diabetic versus idiopathic polyneuropathy. METHODS: Thirty-three patients with idiopathic or diabetic polyneuropathy who had undergone Dellon nerve decompression in the lower extremity between 2011 and 2013 were included in the retrospective study. Pain (numeric rating scale [NRS] 0-10; 0, no pain; 10, worst imaginable pain), tingling, numbness, Hoffmann-Tinel sign, and Semes-Weinstein monofilament were assessed in 20 patients with diabetic polyneuropathy and in 13 patients with idiopathic polyneuropathy. RESULTS: Three months after surgery, a significant reduction in pain was evident in patients with diabetic polyneuropathy, from a preoperative level of NRS 4.9 (minimum, 0; maximum, 10) to 2 (minimum, 0; maximum, 8; P = 0.005). Ninety percent of patients complained of tingling ( P = 0.000) before surgery and 18% after surgery, whereas 100% complained of numbness before surgery and 41% ( P = 0.000) after surgery. One hundred percent of patients had no measurable surface sensitivity before surgery (measured with the Semes-Weinstein monofilament), whereas 3 months after surgery, only 24% of patients still had no measurable surface sensitivity ( P = 0.000). A positive Hoffmann-Tinel sign was recorded in 85% of patients before surgery and only in 11% 3 months after surgery ( P = 0.000). In the case of patients with idiopathic polyneuropathy, a reduction in pain was evident 3 months after surgery, from a preoperative level of NRS 3.9 (minimum, 0; maximum, 9) to 2.2 (minimum, 0; maximum, 9; P = 0.058). Seventy-seven percent of patients complained of tingling before surgery and 42% after surgery ( P = 0.111), whereas 92% complained of numbness before surgery and 50% after surgery ( P = 0.030). Seventy-seven percent of patients had no measurable surface sensitivity before surgery (measured with the Semes-Weinstein monofilament), whereas 3 months after surgery, only 33% of patients still had no measurable surface sensitivity ( P = 0.047). A positive Hoffmann-Tinel sign was recorded in 62% of patients before surgery and only in 17% 3 months after surgery ( P = 0.041). CONCLUSIONS: Not only patients with diabetic polyneuropathy but also those with idiopathic polyneuropathy benefit from Dellon nerve decompression surgery in the lower extremities.

Temporal Trends in Distal Symmetric Polyneuropathy in Type 2 Diabetes: The Fremantle Diabetes Study.

CONTEXT: Macrovascular outcomes in type 2 diabetes have improved over recent decades. There are scant equivalent distal symmetric polyneuropathy (DSPN) data. OBJECTIVE: This work aimed to characterize temporal changes in DSPN prevalence and incidence rates (IRs) in community-based Australians. METHODS: An observational study was conducted among an urban population. Participants included individuals with type 2 diabetes from the Fremantle Diabetes Study phases I (FDS1; n = 1296 recruited 1993-1996) and II (FDS2; n = 1509 recruited 2008-2011). Main outcome measures included Michigan Neuropathy Screening Instrument (MNSI) clinical grading. RESULTS: DSPN prevalence by 8-point MNSI was 30.8% (FDS1) and 58.9% (FDS2; P < .001), and by 6-point (excluding foot appearance) and 2-point (biothesiometry alone) MNSI was 37.5% and 35.7% (P = .336), and 33.8% and 38.7% (P = .011), respectively. Given between-phase changes in appearance assessment, 8-point MNSI data were not analyzed further. In multivariable analysis, FDS2 vs FDS1 participation was associated with 6-point (odds ratio (95% CI) 0.68 (0.56-0.83); P < .001) but not 2-point (0.90 (0.74-1.11); P = .326) MNSI DSPN prevalence. Four-year DSPN IRs (95% CI) for 6-point MNSI were 13.6 (12.0-15.4) and 17.6 (15.9-19.4)/100 person-years in FDS1 and FDS2, respectively (IR ratio [IRR] 1.31 [1.12-1.55]; P < .001), and for 2-point MNSI were 13.9 (12.3-15.8) and 7.4 (16.3-8.6/100 person-years; IRR 0.53 [0.43-0.64]; P < .001). FDS2 vs FDS1 independently predicted incident DSPN for 6-point (hazard ratio [95% CI] 1.25 [1.06-1.48]; P = .009) and 2-point (0.42 [0.33-0.55]; P < .001) MNSI. CONCLUSION: DSPN prevalence was lower or equivalent in FDS2 vs FDS1, and its incidence was greater or lower, in multivariable models depending on the MNSI features used.

Nitrous-oxide-induced polyneuropathy and subacute combined degeneration of the spine: clinical and diagnostic characteristics in 70 patients, with focus on electrodiagnostic studies.

BACKGROUND AND PURPOSE: Nitrous oxide (N2 O) induced neurological symptoms are increasingly encountered. Our aim is to provide clinical and diagnostic characteristics with a focus on electrodiagnostic studies. METHODS: Patients with neurological sequelae due to N2 O presenting in our hospital between November 2018 and December 2021 reporting clinical and diagnostic data were retrospectively reviewed. RESULTS: Seventy patients (median 22 years) were included. Median N2 O usage was 4 kg/week during 12 months. Patients' history revealed a higher rate of sensory symptoms compared to motor (97% vs. 57%) and 77% walking difficulties. Clinical diagnosis was polyneuropathy (PNP) in 44%, subacute combined degeneration (SCD) of the spine in 19%, both in 37%. Median vitamin B12 level was low (159 pmol/L), normal in 16%. The median methylmalonic acid was increased (2.66 µmol/L). Electrodiagnostic abnormalities were observed in 91%, with 72% fulfilling axonal PNP criteria, 20% showing mild to intermediate slowing. One patient fulfilled demyelinating PNP criteria not related to N2 O abuse (Charcot-Marie-Tooth type 1a). More prominent motor nerve conduction abnormalities were found; lower limbs were more affected. In 64% with normal conduction, myography showed signs of axonal loss. Magnetic resonance imaging showed cervical myelopathy in 58% involving generally five to six segments. CONCLUSIONS: Nitrous oxide (N2 O) leads to neurological symptoms by causing PNP and/or SCD primarily involving the legs. Distinguishing PNP and SCD clinically was shown to be insufficient. Electrodiagnostic studies showed axonal PNP. Demyelinating PNP due to N2 O abuse was not present in our cohort. Therefore, further diagnostic work-up is warranted if demyelinating features are present.

EFFECT OF NON-ALCOHOLIC FATTY LIVER DISEASE ON THE COURSE OF DIABETIC POLYNEUROPATHY IN PATIENTS WITH TYPE 2 DIABETES MELLITUS.

OBJECTIVE: The aim: To study the peculiarities of diabetic polyneuropathy in patients with type 2 diabetes mellitus and concomitant NAFLD. PATIENTS AND METHODS: Materials and methods: We examined 75 patients with type 2 diabetes mellitus, including 31 (41.3%) women and 44 (58.7%) men. The main group included 35 patients with NAFLD (46.7%), and the control group included 40 patients without NAFLD (53.3%). The severity of polyneuropathy was assessed using the Toronto clinical neuropathy score. The presence of neuropathic pain syndrome in patients allowed us to divide patients into groups with painful or painless forms of diabetic polyneuropathy. The electroneuromyographic examination was used to study nerve conduction parameters, namely peroneal motor nerve conduction velocity (PMNCV), sensory nerve action potential (SNAP), and sensory nerve conduction velocity (SNCV). RESULTS: Results: The proportion of patients who did not have diabetic polyneuropathy in the NAFLD group was 12.5%, and in the group without NAFLD - 87.2%. The frequency of diabetic polyneuropathy was higher in the main group, namely: mild, moderate, and severe polyneuropathy was 80%, 56% and 59.3%, respectively, compared to the control group - 20%, 44%, 40.7% (p=0.02). The painful form of DPN was more common in patients of the main group than in the control group, respectively 69.8% and 30.2% (p=0.01). The degree of liver fibrosis did not affect the course of DPN. The study of nerve conduction by PMNCV, SNAP, and SNCV parameters showed that PMNCV was higher in the NAFLD group, and SNAP and SNCV - in the control group, but without statistical significance (p>0.05). CONCLUSION: Conclusions: In patients with type 2 diabetes mellitus, the presence of NAFLD affects the severity of diabetic polyneuropathy and increases the risk of painful DPN. The degree of liver fibrosis did not show an effect on the development of diabetic polyneuropathy. ENMG parameters did not demonstrate a statistically significant difference in the study groups.

Illness Weakness, Polyneuropathy and Myopathy: Diagnosis, treatment, and long-term outcomes.

BACKGROUND: Severe weakness associated with critical illness (CIW) is common. This narrative review summarizes the latest scientific insights and proposes a guide for clinicians to optimize the diagnosis and management of the CIW during the various stages of the disease from the ICU to the community stage. MAIN BODY: CIW arises as diffuse, symmetrical weakness after ICU admission, which is an important differentiating factor from other diseases causing non-symmetrical muscle weakness or paralysis. In patients with adequate cognitive function, CIW can be easily diagnosed at the bedside using manual muscle testing, which should be routinely conducted until ICU discharge. In patients with delirium or coma or those with prolonged, severe weakness, specific neurophysiological investigations and, in selected cases, muscle biopsy are recommended. With these exams, CIW can be differentiated into critical illness polyneuropathy or myopathy, which often coexist. On the general ward, CIW is seen in patients with prolonged previous ICU treatment, or in those developing a new sepsis. Respiratory muscle weakness can cause neuromuscular respiratory failure, which needs prompt recognition and rapid treatment to avoid life-threatening situations. Active rehabilitation should be reassessed and tailored to the new patient's condition to reduce the risk of disease progression. CIW is associated with long-term physical, cognitive and mental impairments, which emphasizes the need for a multidisciplinary model of care. Follow-up clinics for patients surviving critical illness may serve this purpose by providing direct clinical support to patients, managing referrals to other specialists and general practitioners, and serving as a platform for research to describe the natural history of post-intensive care syndrome and to identify new therapeutic interventions. This surveillance should include an assessment of the activities of daily living, mood, and functional mobility. Finally, nutritional status should be longitudinally assessed in all ICU survivors and incorporated into a patient-centered nutritional approach guided by a dietician. CONCLUSIONS: Early ICU mobilization combined with the best evidence-based ICU practices can effectively reduce short-term weakness. Multi-professional collaborations are needed to guarantee a multi-dimensional evaluation and unitary community care programs for survivors of critical illnesses.

Diagnostic accuracy of the 5.07 monofilament test for diabetes polyneuropathy: influence of age, sex, neuropathic pain and neuropathy severity.

INTRODUCTION: There is a need for simple and cheap diagnostic tools for diabetic polyneuropathy (DPN). We aimed to assess the diagnostic accuracy of the 5.07/10 g monofilament test in patients referred to polyneuropathy assessments, as well as to examine how disease severity, age, sex and neuropathic pain (NP) impact diagnostic accuracy. RESEARCH DESIGN AND METHODS: Five Norwegian university hospitals recruited patients with diabetes aged 18-70 referred to neurological outpatient clinics for polyneuropathy assessments. The 5.07/10 g Semmes-Weinstein monofilament examination (SWME) was validated against the Toronto consensus for diagnosing diabetic neuropathies; the results were stratified by age, sex and NP. Disease severity was graded by a combined nerve conduction study (NCS) Z-score, and logistic regression was applied to assess whether disease severity was a predictor of diagnostic accuracy. RESULTS: In total, 506 patients were included in the study. Global sensitivity was 0.60 (95% CI 0.55, 0.66), specificity 0.82 (95% CI 0.75, 0.87), positive and negative predictive values were 0.86 (95% CI 0.81, 0.90) and 0.52 (95% CI 0.46, 0.58), respectively, positive and negative likelihood ratios were 3.28 (95% CI 2.37, 4.53) and 0.49 (95% CI 0.42, 0.57), respectively. The SWME was less sensitive in females (0.43), had lower specificity in patients with NP (0.56), and performed worse in patients ≥50 years. NCS-based disease severity did not affect diagnostic accuracy (OR 1.15, 95% CI 0.95, 1.40). CONCLUSIONS: This multicenter study demonstrates poor diagnostic performance for the 5.07/10 g SWME in patients with diabetes referred to polyneuropathy assessments; it is particularly unsuited for female patients and those with NP. The diagnostic accuracy of the SWME was not influenced by NCS-based disease severity, demonstrating that it does not perform better in patients with later stages of DPN. We do not recommend the use of the 5.07/10 g monofilament in the evaluation of patients with diabetes referred to polyneuropathy assessments.

Toxic Neuropathies.

OBJECTIVE: The purpose of this article is to provide an overview and update on the most clinically relevant toxic neuropathies. LATEST DEVELOPMENTS: Broadly, toxic neuropathies were previously quite rare with the notable exception of neuropathy from alcohol or older chemotherapeutics. The development of newer therapies, particularly immunotherapy to treat malignancy, has resulted in a substantial increase in the occurrence of toxic neuropathies that require timely recognition and treatment. The understanding of other toxic neuropathies continues to evolve, such as statin-induced neuropathy, which new evidence suggests is much less common than previously suspected. ESSENTIAL POINTS: Toxic neuropathies can be caused by medications, supplements, and recreational substances that injure peripheral nerves. Medications have evolved in the past 2 decades, as have the types of neuropathies that can be seen as related toxicities. In some areas of medicine, new classes and generations of drugs are associated with a lower incidence of toxic neuropathy.

Paraproteinemic Neuropathies.

OBJECTIVE: Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each. LATEST DEVELOPMENTS: Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis. ESSENTIAL POINTS: Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.

Eplontersen for Hereditary Transthyretin Amyloidosis With Polyneuropathy.

Importance: Transthyretin gene silencing is an emerging treatment strategy for hereditary transthyretin (ATTRv) amyloidosis. Objective: To evaluate eplontersen, an investigational ligand-conjugated antisense oligonucleotide, in ATTRv polyneuropathy. Design, Setting, and Participants: NEURO-TTRansform was an open-label, single-group, phase 3 trial conducted at 40 sites across 15 countries (December 2019-April 2023) in 168 adults with Coutinho stage 1 or 2 ATTRv polyneuropathy, Neuropathy Impairment Score 10-130, and a documented TTR variant. Patients treated with placebo from NEURO-TTR (NCT01737398; March 2013-November 2017), an inotersen trial with similar eligibility criteria and end points, served as a historical placebo ("placebo") group. Interventions: Subcutaneous eplontersen (45 mg every 4 weeks; n = 144); a small reference group received subcutaneous inotersen (300 mg weekly; n = 24); subcutaneous placebo weekly (in NEURO-TTR; n = 60). Main Outcomes and Measures: Primary efficacy end points at week 65/66 were changes from baseline in serum transthyretin concentration, modified Neuropathy Impairment Score +7 (mNIS+7) composite score (scoring range, -22.3 to 346.3; higher scores indicate poorer function), and Norfolk Quality of Life Questionnaire-Diabetic Neuropathy (Norfolk QoL-DN) total score (scoring range, -4 to 136; higher scores indicate poorer quality of life). Analyses of efficacy end points were based on a mixed-effects model with repeated measures adjusted by propensity score weights. Results: Among 144 eplontersen-treated patients (mean age, 53.0 years; 69% male), 136 (94.4%) completed week-66 follow-up; among 60 placebo patients (mean age, 59.5 years; 68% male), 52 (86.7%) completed week-66 follow-up. At week 65, adjusted mean percentage reduction in serum transthyretin was -81.7% with eplontersen and -11.2% with placebo (difference, -70.4% [95% CI, -75.2% to -65.7%]; P < .001). Adjusted mean change from baseline to week 66 was lower (better) with eplontersen vs placebo for mNIS+7 composite score (0.3 vs 25.1; difference, -24.8 [95% CI, -31.0 to -18.6; P < .001) and for Norfolk QoL-DN (-5.5 vs 14.2; difference, -19.7 [95% CI, -25.6 to -13.8]; P < .001). Adverse events by week 66 that led to study drug discontinuation occurred in 6 patients (4%) in the eplontersen group vs 2 (3%) in the placebo group. Through week 66, there were 2 deaths in the eplontersen group consistent with known disease-related sequelae (cardiac arrhythmia; intracerebral hemorrhage); there were no deaths in the placebo group. Conclusions and Relevance: In patients with ATTRv polyneuropathy, the eplontersen treatment group demonstrated changes consistent with significantly lowered serum transthyretin concentration, less neuropathy impairment, and better quality of life compared with a historical placebo. Trial Registration: ClinicalTrials.gov Identifier: NCT04136184; EU Clinical Trials Register: EudraCT 2019-001698-10.

Anti-SRP Myopathy with Sensorimotor Polyneuropathy: A Case Report.

PURPOSE: Anti-signal recognition particle (SRP) myopathy is a subtype of immune-mediated necrotizing myopathy. It rarely presents with extramuscular features, involving the skin, lung, and heart. This paper presents a case of anti-SRP myopathy associated with sensorimotor polyneuropathy. CASE REPORT: A 33-year-old woman with no history of systemic disease presented to our hospital with weakness and numbness of the lower limbs for 1 year. Electromyography and nerve conduction study (NCS) revealed combined myopathy and axonal sensorimotor polyneuropathy. Blood examination revealed increased levels of serum muscle enzymes and anti-SRP antibodies. T1-weighted magnetic resonance imaging revealed diffuse muscular hyperintensities in the thighs, indicative of fatty replacement. She was administered methylprednisolone pulse therapy, followed by oral prednisolone and azathioprine. Muscle power increased, and serum muscle enzyme levels decreased significantly. Subsequent NCS performed 2 years later revealed persistent axonal degeneration in the lower limbs. CONCLUSION: Anti-SRP myopathy can present with sensorimotor polyneuropathy. Thus, the possibility that the same pathological process affected the skeletal muscles and peripheral nerves should be considered.

Peripheral polyneuropathy in children and young adults with ataxia-telangiectasia.

BACKGROUND AND PURPOSE: Ataxia-telangiectasia (A-T) is a rare, autosomal recessive, multisystem disorder that leads to progressive neurodegeneration with cerebellar ataxia and peripheral polyneuropathy. Cerebellar neurodegeneration is well described in A-T. However, peripheral nervous system involvement is an underdiagnosed but important additional target for supportive and systemic therapies. The aim of this study was to conduct neurophysiological measurements to assess peripheral neurodegeneration and the development of age-dependent neuropathy in A-T. METHODS: In this prospective study, 42 classical A-T patients were assessed. The motor and sensory nerve conduction of the median and tibial nerves was evaluated. Data were compared to published standard values and a healthy age- and gender-matched control group of 23 participants. Ataxia scores (Klockgether, Scale for the Assessment and Rating of Ataxia) were also assessed. RESULTS: In A-T, neurophysiological assessment revealed neuropathic changes as early as the first year of life. Subjective symptomatology of neuropathy is rarely described. In the upper extremities, motor neuropathy was predominantly that of a demyelinating type and sensory neuropathy was predominantly that of a mixed type. In the lower extremities, motor and sensory neuropathy was predominantly that of a mixed type. We found significant correlations between age and the development of motor and sensory polyneuropathy in A-T compared with healthy controls (p < 0.001). CONCLUSIONS: In A-T, polyneuropathy occurs mostly subclinically as early as the first year of life. The current study of a large national A-T cohort demonstrates that development of neuropathy in A-T differs in the upper and lower extremities.

[Neurological manifestations of ATTR amyloidosis]. / Neurologische Manifestationen der ATTR-Amyloidose.

Transthyretin amyloidosis (ATTR) is a rare disease in which the protein transthyretin (TTR) is deposited in the form of amyloid fibrils in various tissues and organs and secondarily leads to functional impairment, especially in peripheral nerves and the heart. A differentiation is made between hereditary and sporadic forms. The hereditary variant is inherited in an autosomal dominant manner and usually occurs in the younger to middle-aged, while the sporadic form occurs in older age and has no known genetic cause. Typical signs of hereditary ATTR amyloidosis (ATTRv, v for variant) include a rapidly progressing sensorimotor and autonomic polyneuropathy (PNP), cardiac dysfunction as well as ocular and gastrointestinal symptoms. A carpal tunnel syndrome often precedes the manifestation. Various options (tafamidis, patisiran, inotersen or vutrisiran) are available for the treatment of patients with ATTRv with PNP in Germany, depending on the severity. In the sporadic variant of wild-type ATTR amyloidosis (ATTRwt), symptoms of progressive cardiomyopathy are usually prominent; however, neurological assessment of these patients often also reveals a concomitant sensory ataxic PNP. The tetramer stabilizer tafamidis can be used for treatment. Because of this complex presentation, the management of patients with ATTR amyloidosis should be performed in interdisciplinary centers specialized in amyloidosis.

Cardiovascular autonomic neuropathy in patients with type 2 diabetes with and without sensorimotor polyneuropathy.

BACKGROUND AND AIMS: Cardiovascular autonomic neuropathy (CAN) in patients with diabetes is associated with poor prognosis. We aimed to assess signs of CAN and autonomic symptoms and to investigate the impact of sensorimotor neuropathy on CAN by examining type 2 diabetes patients with (DPN [distal sensorimotor polyneuropathy]) and without distal sensorimotor polyneuropathy (noDPN) and healthy controls (HC). Secondarily, we aimed to describe the characteristics of patients with CAN. METHODS: A population of 374 subjects from a previously described cohort of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) were included. Subjects were examined with the Vagus™ device for the diagnosis of CAN, where two or more abnormal cardiovascular autonomic reflex tests indicate definite CAN. Autonomic symptoms were assessed with Composite Autonomic Symptom Score 31 (COMPASS 31) questionnaire. DPN was defined according to the Toronto consensus panel definition. RESULTS: Definite CAN was present in 22% with DPN, 7% without DPN and 3% of HC, and 91% of patients with definite CAN had DPN. Patients with DPN and definite CAN reported higher COMPASS 31 scores compared to patients with noDPN (20.0 vs. 8.3, p < 0.001) and no CAN (22.1 vs. 12.3, p = 0.01). CAN was associated with HbA1c and age in a multivariate logistic regression analysis but was not associated with IEFND or triglycerides. INTERPRETATION: One in five patients with DPN have CAN and specific CAN characteristics may help identify patients at risk for developing this severe diabetic complication. Autonomic symptoms were strongly associated with having both DPN and CAN, but too unspecific for diagnosing CAN.

Electrochemical skin conductances values and clinical factors affecting sudomotor dysfunction in patients with prediabetes, type 1 diabetes, and type 2 diabetes: A single center experience.

BACKGROUND AND AIM: Sudomotor dysfunction is linked to small fibers damage. We investigated sudomotor dysfunction in a large group of participants with diabetes, prediabetes, and nondiabetic healthy subjects. This study aimed to complete knowledge on sudomotor dysfunction in this population, especially regarding the threshold values for the electrochemical skin conductance (ESC) and factors affecting it. MATERIALS AND METHODS: A total of 690 volunteers in four groups were included in the study (type 1 [T1DG]: n = 80, 61.3% women; type 2 diabetes [T2DG]: n = 438, 63.5% women; prediabetes [Pre-DG]: n = 88, 80.7% women; healthy control [HC-G]: n = 84, 67.5% women). All subjects were investigated for clinical diabetic peripheral polyneuropathy and sudomotor dysfunction. The characteristics of participants obtained from outpatient records were evaluated. We used the Sudoscan device to measure ESC which was normalized for BMI, to improve the discriminative capability of the method. RESULTS: Diabetic polyneuropathy was found in 17.5% of T1DG, 27.4% of T1DG, and 10.2% of Pre-DG. The mean ESC/BMI was lower in subgroups with diabetic polyneuropathy than those without. Mean ESC/BMI was lowest in T2DG and highest in HC-G but comparable in T1DG and Pre-DG. We accepted the "mean ESC/BMI-1 SD" in the HC-G as the threshold for sudomotor dysfunction. Accordingly, the prevalence of sudomotor dysfunction was 18.8%, 44.3%, 59.1%, and 15% in T1DG, T2DG, Pre-DG, and HC-G, respectively. In T2DG, sudomotor dysfunction was found in 66.7% of persons with retinopathy, of which 56.3% had clinical diabetic polyneuropathy. The prevalence of sudomotor dysfunction in subjects with peripheral artery disease, chronic kidney disease, cardiovascular disease, and hypertension was 46.7%, 47.4%, 43.4%, and 50%, respectively, and 42.9%, 38.9%, 45.5%, and 37.3% of whom in the same order detected with clinical diabetic polyneuropathy. Considering the entire group, a logistic regression model demonstrated that the variables associated with SMD were: retinopathy (OR: 2.969; 95% CI: 1.723, 5.114), female gender (OR: 1.952; 95% CI: 1.287, 2.962), and e-GFR (OR: 0.989; 95% CI: 0.981, 0.998). Since the rate of complications was very low in T1DG, excluding this group, a new model similarly revealed that retinopathy and female gender were associated with SMD, however, the association with e-GFR was disappeared. CONCLUSION: The prevalence of sudomotor dysfunction is high when established peripheral polyneuropathy was present in diabetes. Even though, sudomotor dysfunction can also occur before clinical polyneuropathy in both types of diabetes (T1DG: 18.8%, T2DG 44.3%), prediabetes (59.1%), and nondiabetic healthy subjects (15%). The variables associated with sudomotor dysfunction were retinopathy and female sex. Normalization of ESC for BMI would be a beneficial approach. However, before this method is included in the routine screening programs for diabetic polyneuropathy, large-scale and prospective studies are required to reach a consensus on the pathological threshold values.

Efficacy and safety of high-dose intramuscular vitamin D2 injection in type 2 diabetes mellitus with distal symmetric polyneuropathy combined with vitamin D insufficiency: study protocol for a multicenter, randomized, double-blinded, and placebo-controlled trial.

Background: Distal symmetric polyneuropathy (DSPN) is the most common chronic complication of type 2 diabetes mellitus (T2DM). DSPN may lead to more serious complications, such as diabetic foot ulcer, amputation, and reduced life expectancy. Observational studies have suggested that vitamin D deficiency may be associated with the development of DSPN in T2DM. However, interventional studies have found that low-dose vitamin D supplementation does not significantly improve neuropathy in DSPN. This study aims to evaluate the efficacy and safety of intramuscular injection of high-dose vitamin D (HDVD) in T2DM with DSPN combined with vitamin D insufficiency. Methods and analysis: We will conduct a multicenter, randomized, double-blinded, and placebo-controlled trial in four large hospitals. All eligible participants will be randomly assigned to either the vitamin D2 supplement or placebo control group and injected intramuscularly monthly for 3 months. Additionally, anthropometric measurements and clinical data will be collected at baseline and 3 months. Adverse events will be collected at 1, 2, and 3 months. The primary outcome measure is the change in the mean Michigan Neuropathy Screening Instrument (MNSI) score at baseline and 3 months post-intervention. We will use the gold-standard liquid chromatography-tandem mass spectrometry method to distinguish between 25(OH)D2 and 25(OH)D3 levels. The MNSN score before the intervention will be used as a covariate to compare the changes between both groups before and after the intervention, and the analysis of covariance will be used to analyze the change in the MNSI score after HDVD supplementation. Discussion: Glycemic control alone does not prevent the progression of DSPN in T2DM. Some studies have suggested that vitamin D may improve DSPN; however, the exact dose, method, and duration of vitamin D supplementation are unknown. Additionally, neuropathy repair requires HDVD supplementation to sustain adequate vitamin D levels. This once-a-month intramuscular method avoids daily medication; therefore, compliance is high. This study will be the first randomized controlled trial in China to analyze the efficacy and safety of HDVD supplementation for patients with T2DM and DSPN and will provide new ideas for pharmacological research and clinical treatment of diabetic neuropathy. Clinical trial registration: https://www.chictr.org.cn/, identifier ChiCTR2200062266.

Gut microbiota modulate distal symmetric polyneuropathy in patients with diabetes.

The pathogenic mechanisms underlying distal symmetric polyneuropathy (DSPN), a common neuropathy in patients with diabetes mellitus (DM), are not fully understood. Here, we discover that the gut microbiota from patients with DSPN can induce a phenotype exhibiting more severe peripheral neuropathy in db/db mice. In a randomized, double-blind, and placebo-controlled trial (ChiCTR1800017257), compared to 10 patients who received placebo, DSPN was significantly alleviated in the 22 patients who received fecal microbiota transplants from healthy donors, independent of glycemic control. The gut bacterial genomes that correlated with the Toronto Clinical Scoring System (TCSS) score were organized in two competing guilds. Increased guild 1, which had higher capacity in butyrate production, and decreased guild 2, which harbored more genes in synthetic pathway of endotoxin, were associated with improved gut barrier integrity and decreased proinflammatory cytokine levels. Moreover, matched enterotype between transplants and recipients showed better therapeutic efficacy with more enriched guild 1 and suppressed guild 2. Thus, changes in these two competing guilds may play a causative role in DSPN and have the potential for therapeutic targeting.

A systematic review of the potential consequences of abnormal serum levels of vitamin B6 in people living with Parkinson's disease.

The prevalences of polyneuropathy and epilepsy are higher in people living with Parkinson's disease (PwPD) when compared to older adults. Vitamin B6 is widely available and affordable. PwPD are at higher risk of having abnormal serum levels of vitamin B6, which are associated with polyneuropathy and epilepsy that are potentially preventable and treatable. Potential contributors to abnormal B6 levels in PwPD include age, dietary habits, vitamin supplement misuse, gastrointestinal dysfunction and complex interactions with levodopa. The literature on the potential consequences of abnormal B6 levels in PwPD is limited by a small number of observational studies focused on polyneuropathy and epilepsy. Abnormal B6 levels have been reported in 60 of 145 PwPD (41.4% relative frequency). Low B6 levels were reported in 52 PwPD and high B6 levels were reported in 8 PwPD. There were 14 PwPD, polyneuropathy and low B6. There were 4 PwPD, polyneuropathy and high B6. There were 4 PwPD, epilepsy and low B6. Vitamin B6 level was low in 44.6% of PwPD receiving levodopa-carbidopa intestinal gel and in 30.1% of PwPD receiving oral levodopa-carbidopa. In almost all studies reporting low B6 in PwPD receiving oral levodopa-carbidopa, the dose of levodopa was ≥1000 mg/day. Rigorous epidemiological studies will clarify the prevalence, natural history and clinical relevance of abnormal serum levels of vitamin B6 in PwPD. These studies should account for diet, vitamin supplement use, gastrointestinal dysfunction, concurrent levels of vitamin B12, folate, homocysteine and methylmalonic acid, formulations and dosages of levodopa and other medications commonly used in PwPD.