Variables influencing neuropathic endpoints: the Rochester Diabetic Neuropathy Study of Healthy Subjects

Alcohol-related peripheral neuropathy: Clinico-neurophysiological characteristics and diagnostic utility of the neuropathy symptoms score and the neuropathy impairment score

Alcohol overconsumption is well known to cause damage to the peripheral nervous system, affecting both small and large nerve fibers. The aim of this descriptive study was to investigate peripheral nerve damage, and to correlate clinical, epidemiological and neurophysiological findings, in patients diagnosed with Alcohol Use Disorder (AUD). Ninety alcohol-dependent subjects on inpatient basis were enrolled in this prospective study over a 3-year period. Every subject was assessed by the Neuropathy Symptoms Score (NSS) questionnaire and the Neuropathy Impairment Score (NIS) clinical examination grading scale, followed by Nerve Conduction Studies, Quantitative Sensory Testing and Sympathetic Skin Response (SSR) testing. Peripheral neuropathy was diagnosed in 54 subjects (60%), by abnormal neurophysiological tests and presence of clinical signs or symptoms. Among them, pure large fiber neuropathy (LFN) was found in 18 subjects, pure small fiber neuropathy (SFN) in 12 subjects, and both large and small fiber neuropathy was diagnosed in 24 subjects. Using linear regression, we found that higher NSS and NIS scores correlated with lower amplitudes of the sural sensory nerve action potential and of the SSR. We also found a significant longer duration of alcohol abuse in subjects with neuropathy, using Student's t-test (p = 0.024). Additionally, applying NIS abnormal cut-off score ≥4, using ROC analysis, we predicted the majority of subjects with LFN, confirming 95.23% sensitivity and 93.75% specificity. Our study confirmed that peripheral neuropathy involving large and small nerve fibers, with a symmetrical length-dependent pattern, is common between patients with AUD and related to the duration of the disorder. We suggest that NSS and NIS scales could be used for the assessment of neuropathy in clinical practice, when the essential neurophysiological testing is not available.

Comparison of therapeutic effects of N-Acetylcysteine with pregabalin in improving the clinical symptoms of painful diabetic neuropathy: a randomized, double-blind clinical trial

OBJECTIVES

Painful diabetic neuropathy (PDN) is highly prevalent and annoyingly in patients with diabetes. The aim of this study was to investigate the effects of oral N-acetylcysteine (NAC) compared to pregabalin in PDN.

METHODS

One hundred two eligible patients with type 2 diabetes and PDN were randomly recievied pregabalin (150 mg/day) or N-Acetylcysteine (NAC) (600 mg/ twice a day) for 8 weeks. Mean pain score, Sleep interference score (SIS), Patient Global Impression of Change (PGIC), Clinical Global Impression of Change (CGIC), and also, serum levels of total antioxidant capacity (TAC), total thiol groups (TTG), catalase activity (CAT), nitric oxide (NO), and malondialdehyde (MDA) were assessed at baseline and at the end of the study.

RESULTS

NAC was well tolerated in all patients. The decrease in mean pain scores and increase in SIS was similar between two groups. More improvement in PGIC and CGIC from the baseline was reported in NAC group. NAC, significantly, decreased serum levels of MDA, and NO, but increased TAC, TTG, and CAT. Pregabalin, significantly, decreased serum levels of MDA, and NO and increased TAC.

DISCUSSION

NAC is efficacious in alleviate symptoms of PDN which is probably related to its antioxidant effects.

TRIAL REGISTRATION

The research protocol received approval from the Ethics Committee of Hamadan University of Medical Sciences (IR.UMSHA.REC.1397.137). The trial registry URL and number in Iranian Registry of Clinical Trials (IRCT): https://www.irct.ir/trial/33313 , IRCT20180814040795N2 (Registration date: 2019-01-21, Retrospectively registered).

Neuropathy in prediabetes

Diabetic neuropathies are the most frequent complications of diabetes, contributing to high morbidity, excess mortality, reduced quality of life, and increased healthcare costs. Prediabetes is characterised by glucose levels within an intermediate range above normoglycaemia yet below the diagnostic threshold for diabetes. In 2021, 10.6% and 6.2% of adults worldwide were estimated to have impaired glucose tolerance and impaired fasting glucose, respectively, the majority of whom are unaware of having prediabetes. Evidence has accumulated suggesting that prediabetes is a predictor of cardiovascular disease (CVD) and increased mortality. The past 2 decades have witnessed an extensive debate, particularly among diabetologists and neurologists, as to whether prediabetes is associated with peripheral neuropathy. In this review, we elaborate on the current evidence, particularly from population-based studies supporting an increased risk of distal sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN) in people with prediabetes. Moreover, we discuss whether lifestyle interventions showing efficacy in preventing or delaying the transition from prediabetes to diabetes in persons with prediabetes may also exert favourable effects on the development and progression of DSPN and CAN. This review should help in raising the awareness of and translating the current knowledge on neuropathies in people with prediabetes into clinical practice and public health. The current recommendation that adults who are overweight or obese should be screened for prediabetes and referred to or offered preventive interventions should ultimately culminate in preventing not only CVD but also prediabetic neuropathy.

Age-Related Changes in Neurologic Examination and Sensory Nerve Amplitude in the General Population: Aging of the Peripheral Nervous System

BACKGROUND AND OBJECTIVES

Chronic axonal polyneuropathy is a common disease of the peripheral nervous system with increasing prevalence with age. Typical neurologic signs are present in patients with polyneuropathy but may also occur in individuals without disease. Owing to limited knowledge on normal aging of the peripheral nervous system, it can be difficult to distinguish peripheral nerve dysfunction due to disease from variations in normal aging. Therefore, we described the changes in neurologic examination and nerve conduction studies that accompany aging in the general population.

METHODS

In this cross-sectional population-based study, we screened participants for chronic polyneuropathy in a controlled environment using standardized methods including a symptom questionnaire, neurologic examination, and nerve conduction studies (NCS). Inclusion criteria were 40 years or older and living in a suburb of Rotterdam, the Netherlands. Participants not diagnosed with chronic polyneuropathy, based on the discussion of findings in the screening by an expert team, were included to determine the effect of age (range 41-96 years) on features of neurologic examination and NCS using frequency calculations and quantile regression analysis.

RESULTS

In total, 4,179 participants (mean age 64.5 ± 12.7 years, 54.9% female) were included of whom 3,780 (90.5%) did not fulfil the criteria for polyneuropathy. In the population without polyneuropathy, the frequency of normal features at neurologic examination declined with age, most pronounced for vibration sense at the hallux (from 6.6 [SD ± 1.5] in 40-49 years to 3.6 [SD ± 3.1] in 80 years or older) and Achilles tendon reflexes (absent in 9% in 40-49 years up to 33% in 80 years or older). Superficial pain sensation and patellar tendon reflexes remained stable over time. Sural sensory nerve action potential (SNAP) amplitude declined with age from 11.2 μV in 40-49 years to 3.3 μV in 80 years or older. Nonrecordable SNAP amplitudes were found in 25.1% of the participants older than 80 years, more often in men (30.3%) than in women (21.0%).

DISCUSSION

This study showed the effect of age on features of neurologic examination and sural nerve amplitude in the general population. These findings are helpful to distinguish features suggesting polyneuropathy from variations of normal aging of the peripheral nervous system.

Somatosensory profiling of patients undergoing alcohol withdrawal: Do neuropathic pain and sensory loss represent a problem?

INTRODUCTION

Chronic heavy alcohol use is known to cause neurological complications such as peripheral neuropathy. Concerning the pathophysiology, few sural nerve and skin biopsy studies showed that small fibers might be selectively vulnerable to degeneration in alcohol-related peripheral neuropathy. Pain has rarely been properly evaluated in this pathology. The present study aims at assessing pain intensity, potential neuropathic characteristics as well as the functionality of both small and large nerve sensitive fibers.

METHODS

In this observational study, 27 consecutive adult patients, hospitalized for alcohol withdrawal and 13 healthy controls were recruited. All the participants underwent a quantitative sensory testing (QST) according to the standardized protocol of the German Research Network Neuropathic Pain, a neurological examination and filled standardized questionnaires assessing alcohol consumption and dependence as well as pain characteristics and psychological comorbidities.

RESULTS

Nearly half of the patients (13/27) reported pain. Yet, pain intensity was weak, leading to a low interference with daily life, and its characteristics did not support a neuropathic component. A functional impairment of small nerve fibers was frequently described, with thermal hypoesthesia observed in 52% of patients. Patients with a higher alcohol consumption over the last 2 years showed a greater impairment of small fiber function.

DISCUSSION

Patients report pain but it is however unlikely to be caused by peripheral neuropathy given the non-length-dependent distribution and the absence of neuropathic pain features. Chronic pain in AUD deserves to be better evaluated and managed as it represents an opportunity to improve long-term clinical outcomes, potentially participating to relapse prevention.

The association of peripheral neuropathy detected by monofilament testing with risk of falls and fractures in older adults

BACKGROUND

In persons with diabetes, annual screening for peripheral neuropathy (PN) using monofilament testing is the standard of care. However, PN detected by monofilament testing is common in older adults, even in the absence of diabetes. We aimed to assess the association of PN with risk of falls and fractures in older adults.

METHODS

We included participants in the Atherosclerosis Risk in Communities (ARIC) Study who underwent monofilament testing at visit 6 (2016-2017). Incident falls and fractures were identified based on ICD-9 and ICD-10 codes from active surveillance of all hospitalizations and linkage to Medicare claims. We used Cox models to assess the association of PN with falls and fractures (combined and as separate outcomes) after adjusting for demographics and risk factors for falls.

RESULTS

There were 3617 ARIC participants (mean age 79.4 [SD 4.7] years, 40.8% male, and 21.4% Black adults), of whom 1242 (34.3%) had PN based on monofilament testing. During a median follow-up of 2.5 years, 371 participants had a documented fall, and 475 participants had a documented fracture. The incidence rate (per 1000 person-years) for falls or fractures for participants with PN versus those without PN was 111.1 versus 74.3 (p < 0.001). The age-, sex-, and race-adjusted 3-year cumulative incidence of incident fall or fracture was significantly higher for participants with PN versus those without PN (26.5% vs. 18.4%, p < 0.001). After adjusting for demographics, PN remained independently associated with falls and fractures (HR 1.48, 95% CI 1.26, 1.74). Results were similar for models including traditional risk factors for falls, when falls and fractures were analyzed as separate outcomes, and after adjustment for competing risk of death.

CONCLUSIONS

PN, as measured by monofilament testing, is common in older adults and associated with risk of falls and fracture. Screening with monofilament testing may be warranted to identify older adults at high risk for falls.

Frontiers in diagnostic and therapeutic approaches in diabetic sensorimotor neuropathy (DSPN)

Diabetes sensory polyneuropathy (DSPN) is a significant complication of diabetes affecting up to 50% of patients in their lifetime and approximately 20% of patients suffer from painful diabetes neuropathic pain. DSPN - both painless and painful - leads to considerable morbidity including reduction of quality of life, increased lower limb amputations and is associated with worsening mortality. Significant progress has been made in the understanding of pathogenesis of DSPN and the last decade has seen newer techniques aimed at its earlier diagnosis. The management of painful DSPN remains a challenge despite advances made in the unravelling the pathogenesis of pain and its transmission. This article discusses the heterogenous clinical presentation of DSPN and the need to exclude key differential diagnoses. Furthermore, it reviews in detail the current diagnostic techniques involving both large and small neural fibres, their limitations and advantages and current place in the diagnosis of DSPN. Finally, the management of DSPN including newer pharmacotherapies are also discussed.

Exploring the molecular pathways and therapeutic implications of angiogenesis in neuropathic pain

Recently, much attention has been paid to chronic neuro-inflammatory condition underlying neuropathic pain. It is generally linked with thermal hyperalgesia and tactile allodynia. It results due to injury or infection in the nervous system. The neuropathic pain spectrum covers a variety of pathophysiological states, mostly involved are ischemic injury viral infections associated neuropathies, chemotherapy-induced peripheral neuropathies, autoimmune disorders, traumatic origin, hereditary neuropathies, inflammatory disorders, and channelopathies. In CNS, angiogenesis is evident in inflammation of neurons and pain in bone cancer. The role of chemokines and cytokines is dualistic; their aggressive secretion produces detrimental effects, leading to neuropathic pain. However, whether the angiogenesis contributes and exists in neuropathic pain remains doubtful. In the present review, we elucidated summary of diverse mechanisms of neuropathic pain associated with angiogenesis. Moreover, an overview of multiple targets that have provided insights on the VEGF signaling, signaling through Tie-1 and Tie-2 receptor, erythropoietin pathway promoting axonal growth are also discussed. Because angiogenesis as a result of these signaling, results in inflammation, we focused on the mechanisms of neuropathic pain. These factors are mainly responsible for the activation of post-traumatic regeneration of the PNS and CNS. Furthermore, we also reviewed synthetic and herbal treatments targeting angiogenesis in neuropathic pain.

Ankle Fractures in Diabetic Patients: A Critical Analysis

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Patients with diabetes are at higher risk for complications after surgical fixation of unstable fractures due to impaired neurovascular functioning and wound-healing capabilities.

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Patients with uncontrolled diabetes have higher rates of complications when compared with patients with controlled diabetes.

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Despite higher rates of complications, operative fixation of unstable ankle fractures in diabetic patients reliably leads to a functional lower extremity with an overall lower rate of complications than nonoperative management.

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Operatively and nonoperatively managed ankle fractures in patients with diabetes should remain non-weight-bearing for an extended period of time.

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Discussion of risk of poor outcomes including deep infection, loss of reduction, return to the operating room, and risk of arthrodesis or amputation should be explicitly discussed with patients and families when managing unstable ankle fractures in diabetic patients.

Composite nerve conduction scores and signs for diagnosis and somatic staging of diabetic polyneuropathy: Mid North American ethnic cohort survey

INTRODUCTION/AIMS

In the Diabetes Control and Complications Trial (DCCT), the minimal nerve conduction (NC) criterion for diabetic sensorimotor polyneuropathy (DSPN) was abnormality of NC in more than one peripheral nerve without specifying the attributes of NCs to be evaluated. In the present study, we assess individual and composite scores of NCs meeting the DCCT criterion and signs for improved diagnosis and assessment of DSPN severity.

METHODS

Evaluated were 13 attributes and 6 composite NC scores and signs and symptoms in 395 healthy subjects (HS) and 388 persons with diabetes (DM).

RESULTS

Percent abnormality between subjects with DM and HS was remarkably different among individual attributes and the six composite NC scores. For diagnosis of DSPN using the DCCT criterion, assessment of conduction velocities (CVs) and distal latencies (DLs) provided sensitive diagnoses of DSPN. NC amplitudes provided stronger measures of severity. In studied cohorts, DSPN was staged: N0, no NC abnormality using NC score 2 (CVs and DLs), 60.0%; N1, NC abnormality only, 18.4%; N2, NC abnormality and signs of feet or legs, 16.3%; and N3, NC abnormality and signs of thighs, 5.3%.

DISCUSSION

For sensitive and standard diagnosis of DSPN using the DCCT NC criterion, specifically defined composite scores of CVs and DLs, e.g., score 2, is recommended. A composite score of amplitudes, e.g., score 4, provides a stronger measure of neuropathy severity. Also, provided are HS reference values of evaluated attributes of NCs and estimates of staged severity of DSPN of mid North American DM cohorts.

Stem Cell Therapy in Diabetic Polyneuropathy: Recent Advancements and Future Directions

Diabetic polyneuropathy (DPN) is the most frequent, although neglected, complication of long-term diabetes. Nearly 30% of hospitalized and 20% of community-dwelling patients with diabetes suffer from DPN; the incidence rate is approximately 2% annually. To date, there has been no curable therapy for DPN. Under these circumstances, cell therapy may be a vital candidate for the treatment of DPN. The epidemiology, classification, and treatment options for DPN are disclosed in the current review. Cell-based therapies using bone marrow-derived cells, embryonic stem cells, pluripotent stem cells, endothelial progenitor cells, mesenchymal stem cells, or dental pulp stem cells are our primary concern, which may be a useful treatment option to ease or to stop the progression of DPN. The importance of cryotherapies for treating DPN has been observed in several studies. These findings may help for the future researchers to establish more focused, accurate, effective, alternative, and safe therapy to reduce DPN. Cell-based therapy might be a permanent solution in the treatment and management of diabetes-induced neuropathy.

Peripheral Neuropathy and Vision and Hearing Impairment in US Adults With and Without Diabetes

We aimed to assess the associations of peripheral neuropathy (PN) with vision and hearing impairment among adults aged ≥40 years who attended the lower-extremity disease exam for the National Health and Nutrition Examination Survey (United States, 1999-2004). Overall, 11.8% (standard error (SE), 0.5) of adults had diabetes, 13.2% (SE, 0.5) had PN (26.6% (SE, 1.4) with diabetes, 11.4% (SE, 0.5) without diabetes), 1.6% (SE, 0.1) had vision impairment, and 15.4% (SE, 1.1) had hearing impairment. The prevalence of vision impairment was 3.89% (95% CI: 2.99, 5.05) among adults with PN and 1.29% (95% CI: 1.04, 1.60) among adults without PN (P < 0.001). After adjustment, PN was associated with vision impairment overall (odds ratio (OR) = 1.48, 95% confidence interval (CI): 1.03, 2.13) and among adults without diabetes (OR = 1.80, 95% CI: 1.17, 2.77) but not among adults with diabetes (P for interaction = 0.018). The prevalence of hearing impairment was 26.5% (95% CI: 20.4, 33.7) among adults with PN and 14.2% (95% CI: 12.4, 16.3) among adults without PN (P < 0.001). The association of PN with moderate/severe hearing impairment was significant overall (OR = 2.55, 95% CI: 1.40, 4.64) and among adults without diabetes (OR = 3.26, 95% CI: 1.80, 5.91). Overall, these findings suggest an association between peripheral and audiovisual sensory impairment that is unrelated to diabetes.

Vitamin D in Neurological Diseases

Vitamin D may have multiple effects on the nervous system and its deficiency can represent a possible risk factor for the development of many neurological diseases. Recent studies are also trying to clarify the different effects of vitamin D supplementation over the course of progressive neurological diseases. In this narrative review, we summarise vitamin D chemistry, metabolism, mechanisms of action, and the recommended daily intake. The role of vitamin D on gene transcription and the immune response is also reviewed. Finally, we discuss the scientific evidence that links low 25-hydroxyvitamin D concentrations to the onset and progression of severe neurological diseases, such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, diabetic neuropathy and amyotrophic lateral sclerosis. Completed and ongoing clinical trials on vitamin D supplementation in neurological diseases are listed.

Efficacy and safety of the combined metabolic medication, containing inosine, nicotinamide, riboflavin and succinic acid, for the treatment of diabetic neuropathy: a multicenter randomized, double-blind, placebo-controlled parallel group clinical trial (CYLINDER)

INTRODUCTION

Antioxidants may have positive impact on diabetic polyneuropathy (DPN), presumably due to alleviation of oxidative stress. We aimed to evaluate the efficacy and safety of combination of antioxidants: succinic acid, inosine, nicotinamide, and riboflavin (SINR) in the treatment of DPN.

RESEARCH DESIGN AND METHODS

In a double-blind, placebo-controlled clinical trial, men and women aged 45-74 years with type 2 diabetes and symptomatic DPN, with initial Total Symptom Score (TSS) ˃5, were randomized into experimental (n=109) or placebo (n=107) group. Patients received study medication/placebo intravenously for 10 days, followed by oral administration for 75 days. Statistical significance was defined as a two-tailed p<0.05.

RESULTS

In SINR group, mean TSS change after 12 weeks was -2.65 (±1.46) vs -1.73 (±1.51) in the placebo group (p<0.0001; t-test). Reduction of symptoms in the SINR group was achieved regardless of hemoglobin A1c levels, but better results were observed in patients with initial TSS <7.5. The analysis of TSS subscores revealed statistically significant between-group differences by dynamics of the intensity of paresthesia and of numbness starting from day 11 (p=0.035 and p=0.001, respectively; mixed model); by day 57, statistically significant between-group differences were detected also by dynamics of burning intensity (p=0.005; mixed model). Study limitations are small effect size, moderate proportion of patients with severe DPN symptoms, subjective assessment of outcomes, exclusion of participants who received injectable glucose-lowering medications other than insulins, and patients with uncontrolled and type 1 diabetes.

CONCLUSIONS

The combination of SINR effectively alleviates DPN symptoms in patients with type 2 diabetes.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04649203; Unique Protocol ID: CTF-III-DM-2019).

Seven Years of Selective Genetic Screening Program and Follow-Up of Asymptomatic Carriers With Hereditary Transthyretin Amyloidosis in Bulgaria

Hereditary transthyretin amyloidosis (ATTRv amyloidosis) is a rare, autosomal-dominant (AD) multisystem disorder resulting from the extracellular deposition of amyloid fibrils formed by a destabilized mutant form of transthyretin (TTR), a transport protein predominantly produced by the liver.

In Vivo Reflectance Microscopy of Meissner Corpuscles and Bedside Measures of Large Fiber Sensory Function: A Normative Data Cohort

BACKGROUND AND OBJECTIVES

The goal of this work was to establish age-, sex-, and body dimension-adjusted normal cutoff values for Meissner corpuscle (MC) densities via in vivo reflectance confocal microscopy (RCM), timed vibration sensory thresholds with a 128-Hz tuning fork, and touch-pressure sensory thresholds with standardized monofilaments for clinical and research application.

METHODS

Seventy-seven prospectively recruited individuals without signs or symptoms of peripheral neuropathy or a condition or neurotoxin exposure that can alter sensory function underwent cross-sectional evaluation of MC densities via in vivo RCM, monofilament touch-pressure sensory thresholds, and timed vibration sensory thresholds in nondominant upper and lower extremities. Age-, sex-, and body dimension (e.g., height)-adjusted normal values were developed. The fifth percentile for MC densities and timed vibration thresholds and 95th percentile for MF touch-pressure thresholds were selected as normal cutoff points.

RESULTS

Participants were 9 to 89 years of age. Age and sex were uniformly distributed. Timed vibration and touch-pressure thresholds were less sensitive with increasing age and were more sensitive in the hand than in the leg or foot within individuals. Timed vibration thresholds did not differ by sex or body dimensions. Touch-pressure thresholds were lower (more sensitive) at the thenar eminence and digit V in the hand in women compared to men but otherwise did not differ by sex at other measurement locations. Body dimensions did not affect touch-pressure thresholds. There were no apparent age-related floor effects for the 5th and 95th percentile normal cutoff values for timed vibration or touch-pressure thresholds, respectively. MC densities also declined with age and were highest at digit V and lowest at the arch within individuals. MC densities were affected by sex or body dimensions at all imaging sites, with lower densities seen in male participants or larger individuals. MC densities were quantifiable in the hand of all participants and were associated with touch-pressure thresholds at all locations.

DISCUSSION

This study establishes age-, sex-, and body dimension-adjusted normal cutoff values for 2 easily applied measures of large fiber sensory function and RCM assessment of MC densities for multiple limb locations. These results will aid in the detection and monitoring of peripheral sensory nerve disorders.

Prevalence of peripheral neuropathy defined by monofilament insensitivity in middle-aged and older adults in two US cohorts

Peripheral neuropathy is associated with substantial morbidity, but risk factors other than diabetes are largely uncharacterized. The aim of this study was to describe the prevalence and risk factors for peripheral neuropathy in adults with and without diabetes from two different population-based studies in the US. We performed a cross-sectional analysis of 5200 black and white participants from NHANES (1999–2004, age 40–85 years) and 3362 black and white participants from the ARIC Study (2016–2017, age 70–89 years) who underwent monofilament testing for peripheral neuropathy using a shared protocol. We used logistic regression to quantify age, sex, and race-adjusted risk factor associations for peripheral neuropathy among middle-aged (40–69 years) and older (≥ 70 years) adults. The age, sex, and race-adjusted prevalence of peripheral neuropathy (decreased sensation on monofilament testing) was 10.4% for middle-aged adults in NHANES, 26.8% for older adults in NHANES, and 39.2% for older adults in ARIC. Diabetes was an important risk factor, but more strongly associated with peripheral neuropathy in middle-aged (OR ~ 5 for long-standing diabetes) compared to older adults (ORs ~ 1.5–2). Male sex (ORs ~ 2), black race (ORs ~ 1.3–1.5), and greater height (ORs ~ 1.5–3) were robust risk factors for peripheral neuropathy. Other risk factors included body mass index, education, and peripheral artery disease. The burden of peripheral neuropathy defined by abnormal monofilament testing among older adults is substantial, even among adults without diabetes. Studies are needed to understand the etiology and prognosis of peripheral neuropathy in the absence of diabetes.

Variable differences of nerve conduction amplitudes versus velocities and distal latencies of healthy subjects assessed in ethnic cohorts

Variable differences of nerve conduction amplitudes vs velocities and distal latencies (DLs) of healthy subjects assessed in ethnic cohorts.

INTRODUCTION/AIMS

The variables affecting reference compound muscle (CMAP) and sensory nerve action potential (SNAP) amplitudes as compared to ones affecting conduction velocities and DLs have not been adequately evaluated in previous studies. In this report, this subject is studied in healthy subject cohorts mainly of Northern European extraction, Northern Plains Indians, and Latinos.

METHODS

Nineteen variables and 18 attributes of nerve conductions (NCs) were assessed using highly standard testing conditions and techniques. Classification and Regression Tree analyses were used to assess variable differences among amplitudes, conduction velocities, and DLs.

RESULTS

The most important variable affecting CMAP and SNAP amplitudes was age. For conduction velocities (CVs) and DLs, the variables were height, ethnic cohort, and age.

DISCUSSION

The variables affecting attributes of NCs were similar for the three ethnic cohorts evaluated. The differences of variables affecting amplitudes compared to CVs and DLs need to be taken into account in interpretation of NC results and in setting reference limits for use in medical practice, epidemiology surveys, and therapeutic trials. Scores of CMAP and SNAP amplitudes are suitable measures of sensorimotor polyneuropathy severity, whereas conduction velocities and DLs reflect physiologic/pathologic abnormality of nerve fibers.

Supporting the Assessment of Hereditary Transthyretin Amyloidosis Patients Based On 3-D Gait Analysis and Machine Learning

Hereditary Transthyretin Amyloidosis (vATTR-V30M) is a rare and highly incapacitating sensorimotor neuropathy caused by an inherited mutation (Val30Met), which typically affects gait, among other symptoms. In this context, we investigated the possibility of using machine learning (ML) techniques to build a model(s) that can be used to support the detection of the Val30Met mutation (possibility of developing the disease), as well as symptom onset detection for the disease, given the gait characteristics of a person. These characteristics correspond to 24 gait parameters computed from 3-D body data, provided by a Kinect v2 camera, acquired from a person while walking towards the camera. To build the model(s), different ML algorithms were explored: k-nearest neighbors, decision tree, random forest, support vector machines (SVM), and multilayer perceptron. For a dataset corresponding to 66 subjects (25 healthy controls, 14 asymptomatic mutation carriers, and 27 patients) and several gait cycles per subject, we were able to obtain a model that distinguishes between controls and vATTR-V30M mutation carriers (with or without symptoms) with a mean accuracy of 92% (SVM). We also obtained a model that distinguishes between asymptomatic and symptomatic carriers with a mean accuracy of 98% (SVM). These results are very relevant, since this is the first study that proposes a ML approach to support vATTR-V30M patient assessment based on gait, being a promising foundation for the development of a computer-aided diagnosis tool to help clinicians in the identification and follow-up of this disease. Furthermore, the proposed method may also be used for other neuropathies.

Effects of the ABCB1 c.3435C>T (rs1045642) Polymorphism on Heat Pain Perception in Opioid-Free Adults With Chronic Pain

BACKGROUND

The adenosine triphosphate-binding cassette, subfamily B, member 1 gene (ABCB1) encodes P-glycoprotein (P-gp) that influences the intracellular transport of solutes including endogenous opioid peptides. The primary objective of this study was to determine the effects of the ABCB1 polymorphism c.3435C>T (rs10454642) on heat pain (HP) perception in a group of opioid-free adults with chronic pain.

METHODS

Opioid-free adults with chronic pain consecutively admitted to a pain rehabilitation program comprised the study cohort (N = 134). Individuals were genotyped for the c.3435C>T (rs10454642) polymorphism. The polymorphism was analyzed with nonparametric tests using a dominant (cytosine-cytosine [CC] versus cytosine-thymine [CT] + thymine-thymine [TT]) and recessive (CC + CT versus TT) model of allele effects. Quantitative sensory testing was performed using the Computer Aided Sensory Evaluator IV system.

RESULTS

The distribution of genotypes was 22% (N = 29) for CC, 45% (N = 60) for CT, and 33% (N = 45) for TT (Hardy-Weinberg, P > .1). A significant association was observed between the recessive model and HP threshold. Standardized values of HP threshold were significantly greater in the TT group than the CC + CT group (median difference, -0.77; 95% confidence interval [CI], -1.49 to -0.23; P = .005), and the effect size estimate was small (Cliff delta = 0.30). In the dominant model, no significant difference in HP threshold was observed between the CC and CT + TT groups (median difference, -0.45; 95% CI, -1.15 to 0.00; P = .108).

CONCLUSIONS

These results posit that the efflux of endogenous opioid peptides is reduced in individuals with the TT genotype due to lower expression of P-gp, which, in turn, results in higher HP threshold. This study contributes to the emerging understanding of how the ABCB1 c.3435C>T polymorphism contributes to pain perception in opioid-free adults with chronic pain and provides the foundation for investigating the potential effects of this polymorphism on the clinical course of chronic pain.

Comparison of Clinical Tests for Peripheral Diabetic Neuropathy in a Type 1 Diabetes Cohort

OBJECTIVE

To examine the performance and agreement of 5 modalities for testing sensory neuropathy against a neurothesiometer among Hispanic patients with type 1 diabetes (T1D) in an outpatient setting.

METHODS

A cross-sectional study was conducted at a tertiary reference center in Mexico City. Sensitivity, specificity, predictive values, and likelihood ratios were calculated using a VibraTip device, 128 Hz tuning fork, and the Semmes-Weinstein 5.07/10 g monofilament test, Ipswich touch test (IpTT), and pinprick test (PPT). The VPT obtained using a neurothesiometer was used as the standard. Agreement between tests was calculated using kappa coefficients.

RESULTS

Our study included 78 patients (156 examinations), of whom 56.4% were females. The mean age was 38.2 ± 13.0 years, and the mean body mass index was 24.6 ± 4.8 kg/m². The best sensitivity was found for IpTT and VibraTip (89.7% and 79.3%, respectively), while the PPT and IpTT had the highest positive predictive values (94.4% and 92.9%, respectively). The highest kappa coefficients were obtained for the IpTT vs neurothesiometer (kappa coefficient [κ] = 0.893, P < .001), followed by VibraTip vs neurothesiometer (κ = 0.782, P < .001). The VibraTip vs IpTT also had a substantial agreement (κ= 0.713, P < .001).

CONCLUSION

Our findings demonstrated that the IpTT had the best diagnostic performance and agreement compared with the standard in this cohort of Hispanic patients with T1D. The IpTT is a useful, simple test for diabetic neuropathy screening. These findings support its inclusion in future guidelines for diabetic foot examination.

Peripheral Neuropathy and All-Cause and Cardiovascular Mortality in U.S. Adults : A Prospective Cohort Study

BACKGROUND

Growing evidence indicates that peripheral neuropathy (PN) is common even in the absence of diabetes. However, the clinical sequelae of PN have not been quantified in the general population.

OBJECTIVE

To assess the associations of PN with all-cause and cardiovascular mortality in the general adult population of the United States.

DESIGN

Prospective cohort study.

SETTING

NHANES (National Health and Nutrition Examination Survey), 1999 to 2004.

PARTICIPANTS

7116 adults aged 40 years or older who had standardized monofilament testing for PN.

MEASUREMENTS

Cox regression to evaluate the associations of PN with all-cause and cardiovascular mortality after adjustment for demographic and cardiovascular risk factors, overall and stratified by diabetes status.

RESULTS

The overall prevalence of PN (±SE) was 13.5% ± 0.5% (27.0% ± 1.4% in adults with diabetes and 11.6% ± 0.5% in adults without diabetes). During a median follow-up of 13 years, 2128 participants died, including 488 of cardiovascular causes. Incidence rates (per 1000 person-years) of all-cause mortality were 57.6 (95% CI, 48.4 to 68.7) in adults with diabetes and PN, 34.3 (CI, 30.3 to 38.8) in adults with PN but no diabetes, 27.1 (CI, 23.4 to 31.5) in adults with diabetes but no PN, and 13.0 (CI, 12.1 to 14.0) in adults with no diabetes and no PN. In adjusted models, PN was significantly associated with all-cause mortality (hazard ratio [HR], 1.49 [CI, 1.15 to 1.94]) and cardiovascular mortality (HR, 1.66 [CI, 1.07 to 2.57]) in participants with diabetes. In those without diabetes, PN was significantly associated with all-cause mortality (HR, 1.31 [CI, 1.15 to 1.50]), but the association between PN and cardiovascular mortality was not statistically significant after adjustment (HR, 1.27 [CI, 0.98 to 1.66]).

LIMITATION

Prevalent cardiovascular disease was self-reported, and PN was defined by monofilament testing only.

CONCLUSION

Peripheral neuropathy was common and was independently associated with mortality in the U.S. population, even in the absence of diabetes. These findings suggest that decreased sensation in the foot may be an underrecognized risk factor for death in the general population.

PRIMARY FUNDING SOURCE

National Institute of Diabetes and Digestive and Kidney Diseases and National Heart, Lung, and Blood Institute of the National Institutes of Health.

Early Detection of Diabetic Peripheral Neuropathy: A Focus on Small Nerve Fibres

Diabetic peripheral neuropathy (DPN) is the most common complication of both type 1 and 2 diabetes. As a result, neuropathic pain, diabetic foot ulcers and lower-limb amputations impact drastically on quality of life, contributing to the individual, societal, financial and healthcare burden of diabetes. DPN is diagnosed at a late, often pre-ulcerative stage due to a lack of early systematic screening and the endorsement of monofilament testing which identifies advanced neuropathy only. Compared to the success of the diabetic eye and kidney screening programmes there is clearly an unmet need for an objective reliable biomarker for the detection of early DPN. This article critically appraises research and clinical methods for the diagnosis or screening of early DPN. In brief, functional measures are subjective and are difficult to implement due to technical complexity. Moreover, skin biopsy is invasive, expensive and lacks diagnostic laboratory capacity. Indeed, point-of-care nerve conduction tests are convenient and easy to implement however questions are raised regarding their suitability for use in screening due to the lack of small nerve fibre evaluation. Corneal confocal microscopy (CCM) is a rapid, non-invasive, and reproducible technique to quantify small nerve fibre damage and repair which can be conducted alongside retinopathy screening. CCM identifies early sub-clinical DPN, predicts the development and allows staging of DPN severity. Automated quantification of CCM with AI has enabled enhanced unbiased quantification of small nerve fibres and potentially early diagnosis of DPN. Improved screening tools will prevent and reduce the burden of foot ulceration and amputations with the primary aim of reducing the prevalence of this common microvascular complication.

Identifying risks for severity of neurological symptoms in Hungarian West Nile virus patients

BACKGROUND

West Nile virus (WNV) infections have become increasingly prevalent in certain European countries, including Hungary. Although most human infections do not cause severe symptoms, in approximately 1% of cases WNV infections can lead to severe WNV neuroinvasive disease (WNND) and death. The goal of our study was to assess the neurological status changes of WNV -infected patients admitted to inpatient care and to identify potential risk factors as underlying reasons for severe neurological outcome.

METHODS

We conducted a retrospective chart review of 66 WNV-infected patients from four Hungarian medical centers. Patients' neurological status at hospital admission and at two follow-up intervals (1st follow-up, within 60-90 days and 2nd follow-up, within 150-180 days, after hospital discharge) were assessed. All of the 66 patients in the initial sample had some type of neurological symptoms and 56 patients were diagnosed with WNND. The modified Rankin Scale (mRS) and the West Nile Virus Neurological Index (WNV-N Index), a scoring system designed for the purpose of this study, were used for neurological status assessment. Patients were dichotomized into two categories, "moderately severe" and "severe" based on their neurological status. Descriptive analysis for sample description, stratified analysis for calculation of odds ratio (OR) and logistic regression for continuous input variables, were performed.

RESULTS

The average number of days between the onset of neurological symptoms and hospital admission (the neurological symptom interval) was 6.01 days. Complications during the hospital stay arose in almost a fifth of the patients (18.2%) and 5 patients died. Each day's increase in the neurological symptom interval significantly increased the risk for developing a severe neurological status following hospital admission (0.799-fold and 0.688-fold, based on the WNV-N Index and mRS, respectively). Patients' age, comorbidity, presence of complications and symptoms of malaise, and gait uncertainty were shown to be independent risk factors for severe neurological status.

CONCLUSIONS

Timely hospital admission of patients with neurological symptoms as well as risk assessment by clinicians - possibly with an optimal assessment tool for estimating neurological status- could improve the neurological outcome of WNV-infected patients.

"Complex" Vasovagal Syncope: A Zebra Among Horses

Background: Vasovagal syncope (VVS) occurs due to cerebral hypoperfusion from a fall in blood pressure, with accompanying bradycardia in most cases. Seizure and/or asystole may accompany VVS, though their prediction within the VVS cohort remains elusive.

Objective: To further characterize VVS and to find predictive features of “complex” VVS (defined as VVS associated with seizures and/or asystole).

Methods: We reviewed medical records of all patients who were referred for orthostatic intolerance and had a definite VVS during the head-up tilt table testing (HUTT). The following variables were recorded: cardiovascular indices during HUTT, autonomic testing results, and semiology of asystole and/or seizure when present. Simple frequency and correlation analysis were performed using the ANOVA.

Results: A total of 78 independent VVS were recorded in 60 patients of which 24% were not preceded by presyncope. Vasodepressor (45%) and mixed (38%) VVS were the most prevalent types. Eighteen (23%) were complex VVS; five had an associated seizure (SySz), nine were accompanied by asystole (SyAs), and four had both (SySzAs). Males were significantly more likely to have complex VVS. Mean asystole duration was somewhat longer in the SyAsSz group. The severity of bradycardia significantly correlated with complex VVS and was a predictor of SySz. Autonomic abnormalities were frequent but did not distinguish the two VVS subgroups. Seizures had multiple distinguishing features from those typically associated with epileptic seizures.

Conclusions: The underlying pathophysiologic mechanisms of complex VVS remain unclear, but the severity of cerebral hypoperfusion due to bradycardia likely plays a key role in seizure generation.

Peripheral Neuropathy in the Lower Limbs of Individuals With Spinal Cord Injury or Disease: A Retrospective Study

PURPOSE

This study investigated the frequency and types of peripheral neuropathy in the lower limbs of patients undergoing rehabilitation after traumatic spinal cord injury or spinal cord disease.

METHODS

This study included consecutive patients with spinal cord injury/spinal cord disease who had electrophysiological assessments during their admission in a rehabilitation center from October 2015 to July 2019. Patients with traumatic spinal cord injury were compared with patients with nontraumatic spinal cord disease.

RESULTS

There were 67 patients (52 male patients, 15 female patients; mean age = 56.5 yrs) of whom 36 patients had spinal cord injury and 31 patients had spinal cord disease. Most of the patients were middle-aged men with at least one preexisting medical comorbidity, who were mostly admitted for rehabilitation of cervical, incomplete spinal cord injury/spinal cord disease. Most patients (86.6%) had abnormal electrophysiological studies representing 5.57% of all admissions. A length-dependent polyneuropathy was diagnosed in 0.77% of all admissions (n = 8). The group of patients with spinal cord injury was comparable with the group of patients with spinal cord disease regarding the other baseline data, clinical, and electrophysiological findings.

CONCLUSIONS

Diseases of the peripheral nervous system were similarly found among patients undergoing rehabilitation for either spinal cord injury or spinal cord disease. A length-dependent polyneuropathy was diagnosed in 0.77% of all admissions. Timely diagnosis and proper treatment of the cause of peripheral neuropathies in the lower limbs in these patients may potentially influence rehabilitation protocols and improve patient outcomes.

Turkish version of the Michigan Neuropathy Screening Instrument in the assessment of diabetic peripheral neuropathy: a validity and reliability study

Background/aim

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus (DM). The Michigan Neuropathy Screening Instrument (MNSI) is a simple, brief, and useful screening tool that was designed to assess DPN. The aim of this study was to develop a Turkish version of the MNSI and assess its reliability and validity.

Materials and methods

Eighty-three patients with DM who were divided into two groups according the results of nerve conduction studies (NCS) as having DPN or without DPN were enrolled in this cross-sectional study. The Toronto clinical scoring system, pain detect questionnaire, and NCS were assessed along with the MNSI.

Results

Each section of the MNSI was internally consistent (Cronbach's alpha > 0.70), and the scores of both sections were positively correlated with total MNSI score (r = 0.938; r = 0.908, respectively, p < 0.001). The test-retest reliability of the Turkish version of the MNSI was determined as 0.99 for the total score (intraclass correlation coefficient = 0.996). Using the agreement between MNSI scores and DPN diagnosis by NCS as a gold standard, receiver-operating characteristic (ROC) curve values for section A and section B were estimated as 0.973 and 1.00, respectively. When a cut-off value ≥ 3.0 in section A and a cut-off value ≥ 2.0 in section B were used, we obtained a sensitivity of 97.6% and 100%; a specificity of 63.4% and 97.6%; a positive predictive value of 72.7% and 97.6%; and a negative predictive value of 96.3% and 100%, respectively.

Conclusion

The Turkish version of MNSI is a reliable and valid tool for screening DPN in Turkish patients.

Validation of Neuropad in the Assessment of Peripheral Diabetic Neuropathy in Patients with Diabetes Mellitus Versus the Michigan Neuropathy Screening Instrument, 10g Monofilament Application and Biothesiometer Measurement

Objective:

Sudomotor dysfunction is a feature of Diabetic Peripheral Neuropathy (DPN). The indicator plaster Neuropad can provide an easy and accurate way to diagnose DPN. The aim of the present study was to evaluate Neuropad’s specificity, sensitivity and accuracy in detecting DPN in patients with Diabetes Mellitus (DM).

Methods:

A total of 174 patients with DM (79 with type 1 DM, 88 women), mean age 49.8 ± 16.1 years and mean DM duration 17.3 ± 7.7 years were included in the present study. The following methods were used to diagnose DPN: the Michigan Neuropathy Screening Instrument Questionnaire and Examination (MNSIQ and MNSIE, respectively), application of 10 g monofilament (MONO) and measurement of vibration perception threshold with biothesiometer (BIO). Neuropad was applied to both feet in all patients and according to the presence or absence of color change of the sticker, patients were divided in two groups: group A (n = 82, complete change in color from blue to pink, depicting normal perspiration) and group B (n = 92, incomplete or no change, depicting abnormal perspiration).

Results:

MNSIQ and MNSIE were positive for DPN in 111 and 119 patients, respectively. BIO was abnormal in 109 and MONO in 59 patients. Sensitivity of Neuropad testing was 95% vs. MONO, 73% vs. BIO, 73% vs. MNSIE and 75% vs. ΜNSIQ. Specificity was 69, 81, 90 and 92%, respectively and accuracy of the test was 78, 76, 78 and 83%, respectively.

Conclusion:

Neuropad has a high sensitivity and specificity in detecting DPN vs. MNSIQ, MNSIE and BIO. Neuropad has a high sensitivity but moderate specificity vs. MONO. The accuracy of the test was high in all measurements.

Diabetic Peripheral Neuropathy: Diagnosis and Treatment

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effect of catechol-O-methyltransferase (rs4680) single-nucleotide polymorphism on opioid-induced hyperalgesia in adults with chronic pain

The catechol-O-methyltransferase Val158Met polymorphism has been associated with alterations in pain perception, but the influence of the polymorphism on pain perception in patients with chronic pain receiving daily opioid therapy has not been previously reported. The primary aim of this study was to investigate the effects of the catechol-O-methyltransferase Val158Met polymorphism on heat pain perception in a cohort of adults receiving daily opioid therapy for chronic pain. Adults with chronic pain consecutively admitted to an outpatient pain rehabilitation program who met inclusion criteria and were receiving daily opioid therapy were recruited for study participation (N = 142). Individuals were genotyped for catechol-O-methyltransferase Val158Met (rs4680), and the polymorphism was analyzed using an additive and codominant genotype models. The distribution of the Val158Met genotypes was 25% for Val/Val, 41% for Val/Met and 34% for Met/Met (Hardy-Weinberg, P > 0.05). A main effect of genotype was observed for heat pain perception ( P = 0.028). Under the codominant model of allele effects, exploratory post hoc pairwise comparisons adjusted for morphine equivalent dose and pain catastrophizing demonstrated that individuals with the Val/Met genotype were hyperalgesic compared to individuals with the Val/Val ( P = 0.039) and Met/Met ( P = 0.023) genotypes. No significant association was observed between heat pain perception and genotype under the additive model of allele effects. Among patients with chronic pain who were receiving daily opioids, the Val/Met genotype was associated with hyperalgesia using a measure of heat pain perception that has been previously indicative of opioid-induced hyperalgesia in other heterogeneous samples of adults with chronic pain. This study contributes to the emerging understanding of how catechol-O-methyltransferase activity affects pain perception in the context of daily opioid use, and these findings may be useful in the design of future trials aimed at investigating the potential efficacy of ß-2 adrenergic receptor antagonism for opioid-induced hyperalgesia.

Pharmacological treatment for familial amyloid polyneuropathy

BACKGROUND

Disease-modifying pharmacological agents for transthyretin (TTR)-related familial amyloid polyneuropathy (FAP) have become available in the last decade, but evidence on their efficacy and safety is limited. This review focuses on disease-modifying pharmacological treatment for TTR-related and other FAPs, encompassing amyloid kinetic stabilisers, amyloid matrix solvents, and amyloid precursor inhibitors.

OBJECTIVES

To assess and compare the efficacy, acceptability, and tolerability of disease-modifying pharmacological agents for familial amyloid polyneuropathies (FAPs).

SEARCH METHODS

On 18 November 2019, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase. We reviewed reference lists of articles and textbooks on peripheral neuropathies. We also contacted experts in the field. We searched clinical trials registries and manufacturers' websites.

SELECTION CRITERIA

We included randomised clinical trials (RCTs) or quasi-RCTs investigating any disease-modifying pharmacological agent in adults with FAPs. Disability due to FAP progression was the primary outcome. Secondary outcomes were severity of peripheral neuropathy, change in modified body mass index (mBMI), quality of life, severity of depression, mortality, and adverse events during the trial.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

The review included four RCTs involving 655 people with TTR-FAP. The manufacturers of the drugs under investigation funded three of the studies. The trials investigated different drugs versus placebo and we did not conduct a meta-analysis. One RCT compared tafamidis with placebo in early-stage TTR-FAP (128 randomised participants). The trial did not explore our predetermined disability outcome measures. After 18 months, tafamidis might reduce progression of peripheral neuropathy slightly more than placebo (Neuropathy Impairment Score (NIS) in the lower limbs; mean difference (MD) -3.21 points, 95% confidential interval (CI) -5.63 to -0.79; P = 0.009; low-certainty evidence). However, tafamidis might lead to little or no difference in the change of quality of life between groups (Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) total score; MD -4.50 points, 95% CI -11.27 to 2.27; P = 0.19; very low-certainty evidence). No clear between-group difference was found in the numbers of participants who died (risk ratio (RR) 0.65, 95% CI 0.11 to 3.74; P = 0.63; very low-certainty evidence), who dropped out due to adverse events (RR 1.29, 95% CI 0.30 to 5.54; P = 0.73; very low-certainty evidence), or who experienced at least one severe adverse event during the trial (RR 1.16, 95% CI 0.37 to 3.62; P = 0.79; very low-certainty evidence). One RCT compared diflunisal with placebo (130 randomised participants). At month 24, diflunisal might reduce progression of disability (Kumamoto Score; MD -4.90 points, 95% CI -7.89 to -1.91; P = 0.002; low-certainty evidence) and peripheral neuropathy (NIS plus 7 nerve tests; MD -18.10 points, 95% CI -26.03 to -10.17; P < 0.001; low-certainty evidence) more than placebo. After 24 months, changes from baseline in the quality of life measured by the 36-Item Short-Form Health Survey score showed no clear difference between groups for the physical component (MD 6.10 points, 95% CI 2.56 to 9.64; P = 0.001; very low-certainty evidence) and the mental component (MD 4.40 points, 95% CI -0.19 to 8.99; P = 0.063; very low-certainty evidence). There was no clear between-group difference in the number of people who died (RR 0.46, 95% CI 0.15 to 1.41; P = 0.17; very low-certainty evidence), in the number of dropouts due to adverse events (RR 2.06, 95% CI 0.39 to 10.87; P = 0.39; very low-certainty evidence), and in the number of people who experienced at least one severe adverse event (RR 0.77, 95% CI 0.18 to 3.32; P = 0.73; very low-certainty evidence) during the trial. One RCT compared patisiran with placebo (225 randomised participants). After 18 months, patisiran reduced both progression of disability (Rasch-built Overall Disability Scale; least-squares MD 8.90 points, 95% CI 7.00 to 10.80; P < 0.001; moderate-certainty evidence) and peripheral neuropathy (modified NIS plus 7 nerve tests - Alnylam version; least-squares MD -33.99 points, 95% CI -39.86 to -28.13; P < 0.001; moderate-certainty evidence) more than placebo. At month 18, the change in quality of life between groups favoured patisiran (Norfolk QOL-DN total score; least-squares MD -21.10 points, 95% CI -27.20 to -15.00; P < 0.001; low-certainty evidence). There was little or no between-group difference in the number of participants who died (RR 0.61, 95% CI 0.21 to 1.74; P = 0.35; low-certainty evidence), dropped out due to adverse events (RR 0.33, 95% CI 0.13 to 0.82; P = 0.017; low-certainty evidence), or experienced at least one severe adverse event (RR 0.91, 95% CI 0.64 to 1.28; P = 0.58; low-certainty evidence) during the trial. One RCT compared inotersen with placebo (172 randomised participants). The trial did not explore our predetermined disability outcome measures. From baseline to week 66, inotersen reduced progression of peripheral neuropathy more than placebo (modified NIS plus 7 nerve tests - Ionis version; MD -19.73 points, 95% CI -26.50 to -12.96; P < 0.001; moderate-certainty evidence). At week 65, the change in quality of life between groups favoured inotersen (Norfolk QOL-DN total score; MD -10.85 points, 95% CI -17.25 to -4.45; P < 0.001; low-certainty evidence). Inotersen may slightly increase mortality (RR 5.94, 95% CI 0.33 to 105.60; P = 0.22; low-certainty evidence) and occurrence of severe adverse events (RR 1.48, 95% CI 0.85 to 2.57; P = 0.16; low-certainty evidence) compared to placebo. More dropouts due to adverse events were observed in the inotersen than in the placebo group (RR 8.57, 95% CI 1.16 to 63.07; P = 0.035; low-certainty evidence). There were no studies addressing apolipoprotein AI-FAP, gelsolin-FAP, and beta-2-microglobulin-FAP.

AUTHORS' CONCLUSIONS

Evidence on the pharmacological treatment of FAPs from RCTs is limited to TTR-FAP. No studies directly compare disease-modifying pharmacological treatments for TTR-FAP. Results from placebo-controlled trials indicate that tafamidis, diflunisal, patisiran, and inotersen may be beneficial in TTR-FAP, but further investigations are needed. Since direct comparative studies for TTR-FAP will be hampered by sample size and costs required to demonstrate superiority of one drug over another, long-term non-randomised open-label studies monitoring their efficacy and safety are needed.

Subcutaneous tanezumab for osteoarthritis of the hip or knee: efficacy and safety results from a 24-week randomised phase III study with a 24-week follow-up period

Objective

Tanezumab, a nerve growth factor inhibitor, was investigated for osteoarthritis (OA) of the hip or knee in a study with 24-week treatment and 24-week safety follow-up.

Methods

This double-blind, randomised, phase III study enrolled adults in Europe and Japan with moderate-to-severe OA who had not responded to or could not tolerate standard-of-care analgesics. Patients were randomised to tanezumab 2.5 mg or 5 mg subcutaneously or matching placebo every 8 weeks (three doses). Co-primary end points were change from baseline to week 24 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function, and Patient’s Global Assessment of OA (PGA-OA). Joint safety and neurological assessments continued throughout the 48-week study.

Results

From March 2016 to December 2017, 849 patients were randomised and evaluated (placebo n=282, tanezumab 2.5 mg n=283, tanezumab 5 mg n=284). At week 24, there was a statistically significant improvement from baseline for tanezumab 5 mg compared with placebo for WOMAC Pain (least squares mean difference±SE –0.62±0.18, p=0.0006), WOMAC Physical Function (–0.71±0.17, p<0.0001) and PGA-OA (–0.19±0.07, p=0.0051). For tanezumab 2.5 mg, there was a statistically significant improvement in WOMAC Pain and Physical Function, but not PGA-OA. Rapidly progressive osteoarthritis (RPOA) was observed in 1.4% (4/283) and 2.8% (8/284) of patients in the tanezumab 2.5 mg and tanezumab 5 mg groups, respectively and none receiving placebo. Total joint replacements (TJRs) were similarly distributed across all three treatment groups (6.7%–7.8%). Tanezumab-treated patients experienced more paraesthesia (5 mg) and hypoaesthesia (both doses) than placebo.

Conclusion

Tanezumab 5 mg statistically significantly improved pain, physical function and PGA-OA, but tanezumab 2.5 mg only achieved two co-primary end points. RPOA occurred more frequently with tanezumab 5 mg than tanezumab 2.5 mg. TJRs were similarly distributed across all three groups.

Trial registration number

NCT02709486.

Vasomodulation of peripheral blood flow by focused ultrasound potentiates improvement of diabetic neuropathy

OBJECTIVE

Effective treatment methods for diabetic peripheral neuropathy are still lacking. Here, a focused ultrasound (FUS) technique was developed to improve blood flow in diabetic peripheral vessels and potentially treat diabetic peripheral neuropathy.

RESEARCH DESIGN AND METHODS

Male adult Sprague-Dawley rats at 4 weeks poststreptozotocin injections were adopted as models for diabetic neuropathic rats. For single FUS treatment, blood perfusion in the skin of the pad of the middle toe was measured before, during, and after the medial and lateral plantar arteries were treated by FUS. For multiple FUS treatments, blood perfusion measurements, von Frey and hot plate testing and nerve conduction velocity measurements were performed before ultrasonic treatment on the first day of each week, and the microvascular and neural fiber densities in the pad of the toe were measured on the first day of the last week.

RESULTS

The blood perfusion rate significantly increased for 7-10 min in the control and neuropathic rats after a single ultrasound exposure. Multiple ultrasound treatments compared with no treatments significantly increased blood perfusion at the second week and further enhanced perfusion at the third week in the neuropathic rats. Additionally, the paw withdrawal force and latency significantly increased from 34.33±4.55 g and 3.96±0.25 s at the first week to 39.10±5.02 g and 4.77±0.71 s at the second week and to 41.13±2.57 g and 5.24±0.86 s at the third week, respectively. The low nerve conduction velocity in the diabetic rats also improved after the ultrasound treatments. Additionally, ultrasound treatments halted the decrease in microvessel and neural fiber densities in the skin of the diabetic toes. Histologic analysis indicated no damage to the treated arteries or neighboring tissue.

CONCLUSIONS

FUS treatment can increase upstream arterial blood flow in diabetic feet, ameliorate the decrease in downstream microvessel perfusion and halt neuropathic progression.

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.

Serum Adiponectin Levels Are Positively Associated With Diabetic Peripheral Neuropathy in Chinese Patients With Type 2 Diabetes

OBJECTIVE

To investigate the association between serum adiponectin levels and diabetic peripheral neuropathy (DPN) in Chinese type 2 diabetes (T2D) patients.

DESIGN AND METHODS

Two hundred nineteen T2D patients aged 40-79 years were divided into two groups according to whether they had DPN. The systemic levels of five biomarkers were measured using a human adipokine multiplexed bead-based immunoassay. Diabetic peripheral neuropathy diagnostic criteria included both common DPN symptoms and neurological screening tests.

RESULTS

Most features of DPN (n=98) and non-DPN patients (n=121) are similar, but the DPN patients were slightly older, had longer diabetes duration, higher hemoglobin (Hb) A1c, lower estimated glomerular filtration rates (eGFR), less exercise, and used lipid-lowering drugs more often. Serum adiponectin levels of DPN patients were higher than that of non-DPN patients (8.13 vs. 9.63 mg/ml, P = 0.004). Serum adiponectin levels were positively associated with DPN after adjusting for age, gender, body mass index, hypertension, HbA1c, alcohol intake, smoking status, physical activity, log-transformed low density lipoprotein cholesterol, lipid-lowering drug usage, eGFR, and diabetes duration {odds ratio (OR) 1.72 [95% confidence interval (CI) 1.02-2.89], P = 0.041}. The OR refers to a doubling in biomarkers.

CONCLUSIONS

Serum adiponectin levels were higher in DPN patients compared to non‑DPN patients in this Chinese T2D population. Serum adiponectin levels were positively associated with DPN presence, independent of multiple confounders.

Plasma neurofilament light chain concentration is increased and correlates with the severity of neuropathy in hereditary transthyretin amyloidosis

Hereditary transthyretin amyloidosis (ATTRm) causes a disabling peripheral neuropathy as part of a multisystem disorder. The recent development of highly effective gene silencing therapies has highlighted the need for effective biomarkers of disease activity to guide the decision of when to start and stop treatment. In this study, we measured plasma neurofilament light chain (pNfL) concentration in 73 patients with ATTR and found that pNfL was significantly raised in ATTRm patients with peripheral neuropathy compared to healthy controls. Furthermore, pNFL correlated with disease severity as defined by established clinical outcome measures in patients for whom this information was available. These findings suggest a potential role of pNfL in monitoring disease activity and progression in ATTRm patients.

Effect of Tanezumab on Joint Pain, Physical Function, and Patient Global Assessment of Osteoarthritis Among Patients With Osteoarthritis of the Hip or Knee: A Randomized Clinical Trial

IMPORTANCE

Patients with osteoarthritis (OA) may remain symptomatic with traditional OA treatments.

OBJECTIVE

To assess 2 subcutaneous tanezumab dosing regimens for OA.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind, multicenter trial from January 2016 to May 14, 2018 (last patient visit). Patients enrolled were 18 years or older with hip or knee OA, inadequate response to OA analgesics, and no radiographic evidence of prespecified joint safety conditions.

INTERVENTIONS

Patients received by subcutaneous administration either tanezumab, 2.5 mg, at day 1 and week 8 (n = 231); tanezumab, 2.5 mg at day 1 and 5 mg at week 8 (ie, tanezumab, 2.5/5 mg; n = 233); or placebo at day 1 and week 8 (n = 232).

MAIN OUTCOMES AND MEASURES

Co-primary end points were change from baseline to week 16 in Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) Pain (0-10, no to extreme pain), WOMAC Physical Function (0-10, no to extreme difficulty), and patient global assessment of osteoarthritis (PGA-OA) (1-5, very good to very poor) scores.

RESULTS

Among 698 patients randomized, 696 received 1 or more treatment doses (mean [SD] age, 60.8 [9.6] years; 65.1% women), and 582 (83.6%) completed the trial. From baseline to 16 weeks, mean WOMAC Pain scores decreased from 7.1 to 3.6 in the tanezumab, 2.5 mg, group; 7.3 to 3.6 in the tanezumab, 2.5/5 mg, group; and 7.3 to 4.4 in the placebo group (least squares mean differences [95% CI] vs placebo were -0.60 [-1.07 to -0.13; P = .01] for tanezumab, 2.5 mg, and -0.73 [-1.20 to -0.26; P = .002] for tanezumab, 2.5/5 mg). Mean WOMAC Physical Function scores decreased from 7.2 to 3.7 in the 2.5-mg group, 7.4 to 3.6 in the 2.5/5-mg group, and 7.4 to 4.5 with placebo (differences vs placebo, -0.66 [-1.14 to -0.19; P = .007] for tanezumab, 2.5 mg, and -0.89 [-1.37 to -0.42; P < .001] for tanezumab, 2.5/5 mg). Mean PGA-OA scores decreased from 3.4 to 2.4 in the 2.5-mg group, 3.5 to 2.4 in the 2.5/5-mg group, and 3.5 to 2.7 with placebo (differences vs placebo, -0.22 [-0.39 to -0.05; P = .01] for tanezumab, 2.5 mg, and -0.25 [-0.41 to -0.08; P = .004] for tanezumab, 2.5/5 mg). Rapidly progressive OA occurred only in tanezumab-treated patients (2.5 mg: n = 5, 2.2%; 2.5/5 mg: n = 1, 0.4%). The incidence of total joint replacements was 8 (3.5%), 16 (6.9%), and 4 (1.7%) in the tanezumab, 2.5 mg; tanezumab, 2.5/5 mg; and placebo groups, respectively.

CONCLUSIONS AND RELEVANCE

Among patients with moderate to severe OA of the knee or hip and inadequate response to standard analgesics, tanezumab, compared with placebo, resulted in statistically significant improvements in scores assessing pain and physical function, and in PGA-OA, although the improvements were modest and tanezumab-treated patients had more joint safety events and total joint replacements. Further research is needed to determine the clinical importance of these efficacy and adverse event findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02697773.

Pooled analysis of tanezumab efficacy and safety with subgroup analyses of phase III clinical trials in patients with osteoarthritis pain of the knee or hip

Purpose

A pooled analysis was conducted to evaluate tanezumab efficacy and safety in patients with osteoarthritis (OA), including subgroup analyses of at-risk patients with diabetes, severe OA symptoms, and those aged ≥65 years.

Patients and methods

Data from phase III placebo-controlled clinical trials of patients with moderate-to-severe OA of the knee or hip were pooled to evaluate tanezumab efficacy (four trials) and safety (nine trials). Patients received intravenous tanezumab, tanezumab plus an oral NSAID (naproxen, celecoxib, or diclofenac), active comparator (naproxen, celecoxib, diclofenac, or oxycodone), or placebo. Efficacy assessments included change from baseline to week 16 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function scores, Patient’s Global Assessment (PGA) of OA, and percentage of patients with ≥30%, ≥50%, ≥70%, and ≥90% improvement in WOMAC pain. Safety assessments included adverse event (AE) documentation and physical and neurologic examinations.

Results

Tanezumab significantly improved all efficacy end points in the overall population. Efficacy in at-risk patient subgroups was similar to the overall population. Incidence of AEs was highest in the tanezumab plus NSAID group and lowest in the placebo group. Incidence of AEs in the tanezumab monotherapy and active comparator groups was similar. Overall incidence of AEs was similar across subgroups. AEs of abnormal peripheral sensation were more frequently reported in tanezumab-treated patients compared with placebo or active comparator. Patients receiving active comparator had a slightly higher incidence of AEs suggestive of postganglionic sympathetic dysfunction.

Conclusion

Tanezumab consistently provided significant improvement of pain, physical function, and PGA in individuals with OA, including patients with diabetes, severe OA symptoms, or aged ≥65 years. No increased safety risk was observed in at-risk patient subgroups.

Trial registration

NCT00733902, NCT00744471, NCT00830063, NCT00863304, NCT00809354, NCT00864097, NCT00863772, NCT01089725, NCT00985621.

Topical treatments for diabetic neuropathic pain

Diabetic neuropathic pain (DNP) has a huge impact on quality of life and can be difficult to treat. Oral treatment is the most frequently used method for DNP, but its use is often limited by systemic side effects. Topical use of drugs as an alternative option for DNP treatment is currently gaining interest. In the present review, a summary is provided of the available agents for topical use in patients with DNP, including lidocaine plasters or patches, capsaicin cream, gel or patches, amitriptyline cream, clonidine gel, ketamine cream, extracts from medicinal plants including nutmeg extracts and Citrullus colocynthis extract oil, and certain compounded topical analgesics. Furthermore, the potential efficacy of these treatments is addressed according to the available clinical research literature. It has been indicated that these topical drugs have the potential to be valuable additional options for the management of DNP, with adequate safety and continuous long-term treatment efficacy. Compounded topical agents are also effective and safe for patients with DNP and could be another area worthy of further investigation based on the strategy of using low-dose, complementary therapies for DNP. The findings indicate that developing topical drugs acting on different targets in the process of DNP is a valuable area of future research.

The pace and prognosis of peripheral sensory loss in advanced age: association with gait speed and falls

Background

Peripheral sensory loss is considered one of many risk factors for gait impairments and falls in older adults, yet no prospective studies have examined changes in touch sensation in the foot over time and their relationship to mobility and falls. Therefore, we aimed to determine the prevalence and progression of peripheral sensory deficits in the feet of older adults, and whether sensory changes are associated with the slowing of gait and development of falls over 5 years.

Methods

Using baseline, and 18 and 60 month followup data from the Maintenance Of Balance, Independent Living, Intellect, and Zest in the Elderly (MOBILIZE) Study in Boston, MA, we determined changes in the ability to detect stimulation of the great toe with Semmes Weinstein monofilaments in 351 older adults. We used covariate-adjusted repeated measures analysis of variance to determine relationships between sensory changes and gait speed or fall rates.

Results

Subjects whose sensory function was consistently impaired over 5 years had a significantly steeper decline in gait speed (− 0.23 m/s; 95% CI: -0.28 to − 0.18) compared to those with consistently intact sensory function (− 0.12 m/s; 95% CI: -0.15 to − 0.08) and those progressing from intact to impaired sensory function (− 0.13 m/s; − 0.16 to − 0.10). Compared to subjects with consistently intact sensation, those whose sensory function progressed to impairment during followup had the greatest risk of falls (adjusted risk ratio = 1.57 (95% confidence interval = 1.12 to 2.22).

Conclusions

Our longitudinal results indicate that a progressive decline in peripheral touch sensation is a risk factor for mobility impairment and falls in older adults.

IL-1β and IL-1Ra Variant Profiles in Turkish Patients with Diabetic Peripheral Neuropathy

BACKGROUND

Diabetic peripheral neuropathy (DPN) is one of the most common complications of Type 2 diabetes mellitus (T2DM). This study was conducted to investigate the possible association between interleukin-1β (IL-1β) rs16944 /IL-1 receptor antagonist (IL-1Ra) VNTR variants and genetic susceptibility to DPN in a Turkish cohort.

METHODS

A total of 200 subjects were enrolled in this study, 98 patients with DPN and 102 cases of age and sex-matched healthy controls. Genotyping was performed for all individuals using PCR-RFLP analysis.

RESULTS

IL-1β rs16944 CC genotype had a 3.20-fold increased risk for DPN (p=0.0003, OR=3.20, 95% Cl:1.72-5.96). IL-1β rs16944 CT genotype was higher in healthy control than patients (p=0.004). IL-1β rs16944 C allele was higher in the patient group compared to controls while T allele was lower in patients than controls (p=0.003). IL-1Ra VNTR a1/a1 and a2/a2 genotypes were lower in DPN patients while a1/a2 genotype was higher in patients (p=0.045). The patients carrying a1/T haplotype had decreased risk of DPN than control groups (p=0.004). The patients carrying a2/a2 genotype had lower HDL level (p=0.039). The subjects carrying a2/a2 genotype had higher total cholesterol level while the subjects carrying a1/a2 genotype had lower total cholesterol (p=0.026 and p=0.037, respectively). IL-1Ra a1 allele was associated with higher HDL level (p=0.041).

CONCLUSION

Findings of this study indicated that the IL-1β rs16944 and IL-1Ra VNTR variants are probably to be associated with susceptibility DPN risk in a Turkish cohort.

Omega-3 polyunsaturated fatty acid supplementation for improving peripheral nerve health: protocol for a systematic review

INTRODUCTION

Damage to peripheral nerves occurs in a variety of health conditions. Preserving nerve integrity, to prevent progressive nerve damage, remains a clinical challenge. Omega-3 polyunsaturated fatty acids (PUFAs) are implicated in the development and maintenance of healthy nerves and may be beneficial for promoting peripheral nerve health. The aim of this systematic review is to assess the effects of oral omega-3 PUFA supplementation on peripheral nerve integrity, including both subjective and objective measures of peripheral nerve structure and/or function.

METHODS AND ANALYSIS

A systematic review of randomised controlled trials that have evaluated the effects of omega-3 PUFA supplementation on peripheral nerve assessments will be conducted. Comprehensive electronic database searches will be performed in Ovid MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), US National Institutes of Health Clinical Trials Registry and the WHO International Clinical Trials Registry Platform. The title, abstract and keywords of identified articles will be assessed for eligibility by two reviewers. Full-text articles will be obtained for all studies judged as eligible or potentially eligible; these studies will be independently assessed by two reviewers to determine eligibility. Disagreements will be resolved by consensus. Risk of bias assessment will be performed using the Cochrane Collaboration risk of bias tool to appraise the quality of included studies. If clinically meaningful, and there are a sufficient number of eligible studies, a meta-analysis will be conducted and a summary of findings table will be provided.

ETHICS AND DISSEMINATION

This is a systematic review that will involve the analysis of previously published data, and therefore ethics approval is not required. A manuscript reporting the results of this systematic review will be published in a peer-reviewed journal and may also be presented at relevant scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42018086297.

The association between Toxoplasma gondii infection and hypertensive disorders in T2DM patients: a case-control study in the Han Chinese population

Type 2 diabetes mellitus (T2DM) is a major global health problem. The rate of infection with Toxoplasma gondii (T. gondii) is more than one-third of the total world population. The effects of T. gondii infection on the risk of diabetic complications and comorbidities are unclear. This study aims to determine the relationship between T. gondii infection and complications of T2DM in the Han Chinese population. We collected 1580 blood samples from T2DM patients and measured the levels of specific IgG antibodies against T. gondii in the sera of these patients using an ELISA assay. A logistic regression analysis was performed to estimate the effect of T. gondii infection on the complications of T2DM, while adjusting for age, gender, and triglyceride level (TG). We applied the multifactor dimensionality reduction (MDR) method to detect the interactions between T. gondii infections, demographic indexes and biochemical indicators among the different complications. Gender (the odds ratio (OR) = 0.63, 95%CI =0.45-0.89, P = 0.008) and TG level (OR = 0.64, 95%CI =0.45-0.89, P = 0.009) were influencing factors in T. gondii infections. T2DM patients who were infected with T. gondii had a 2.34 times risk of developing hypertension than those patients without T. gondii infection (OR = 2.34, 95%CI = 1.12-4.88, P = 0.024). The multiplicative interaction analysis and the additive interaction analysis did not reveal any evidence of interactive effects on diabetic complications and comorbidities. T. gondii might be a factor associated with hypertension in T2DM patients.

Transthyretin familial amyloid polyneuropathy (TTR-FAP): Parameters for early diagnosis

BACKGROUND

Familial transthyretin amyloidosis is a life-threatening disease presenting with sensorimotor and autonomic polyneuropathy. Delayed diagnosis has a detrimental effect on treatment and prognosis. To facilitate diagnosis, we analyzed data patterns of patients with transthyretin familial amyloid polyneuropathy (TTR-FAP) and compared them to polyneuropathies of different etiology for clinical and electrophysiological discriminators.

METHODS

Twenty-four patients with TTR-FAP and 48 patients with diabetic polyneuropathy (dPNP) were investigated (neurological impairment score NIS; neurological disability score NDS) in a cross-sectional design. Both groups were matched for gender and presence of pain. Quantitative sensory testing (QST), sympathetic skin response (SSR), heart rate variability (HRV), and nerve conduction studies (NCV) were performed. Both groups were compared using univariate analysis. In a stepwise discriminant analysis, discriminators between both neuropathies were identified. These discriminators were validated comparing TTR-FAP patients with a cohort of patients with chemotherapy-induced polyneuropathy (CIN) and chronic inflammatory demyelinating neuropathy (CIDP).

RESULTS

TTR-FAP patients scored higher in NDS and NIS and had impaired cold detection (CDT, p = .024), cold-warm discrimination (TSL, p = .019) and mechanical hyperalgesia (MPT, p = .029) at the hands, SSR (upper limb, p = .022) HRV and ulnar and sural NCS (all p < .05) were more affected in TTR-FAP. Ulnar nerve sensory NCV, CDT, and the MPT but not the other parameters discriminated TTR-FAP from dPNP (82% of cases), from CIN (86.7%) and from CIDP (68%; only ulnar sNCV).

CONCLUSION

Low ulnar SNCV, impaired cold perception, and mechanical hyperalgesia at the hands seem to characterize TTR-FAP and might help to differentiate from other polyneuropathies.

Efficacy of a new microvibration sensation measurement device at detecting diabetic peripheral neuropathy using a newly devised finger method

To investigate the efficacy of the finger method using a new microvibration sensation measurement device in the evaluation of diabetic peripheral neuropathy (DPN). A cross‐sectional study of 52 type 2 diabetic outpatients was performed. Patients were evaluated for DPN using American Diabetes Association (ADA) criteria, Michigan Neuropathy Screening Instrument, and the finger method. Patients were classified into probable DPN or non‐DPN groups, according to ADA criteria. The finger method measured peripheral neuropathy vibration (PNV) score of index and middle fingers using the new device in three procedures: PNV 1, PNV 4, and PNV 8. PNV scores ranged from 1 to 30 and were compared between the two groups. The PNV scores were significantly higher in the DPN group (P < .01). The PNV scores for right fingers of DPN and non‐DPN groups were 10.2 ± 7.4 and 3.4 ± 3.3 by PNV 1, 20 ± 4.9 and 10.7 ± 5.3 by PNV 4, and 23.2 ± 4.9 and 14.6 ± 7.8 by PNV 8. Our data suggest that the finger method performed with the new device is useful in the evaluation of DPN.

Interactions of TRAF6 and NLRX1 gene polymorphisms with environmental factors on the susceptibility of type 2 diabetes mellitus vascular complications in a southern Han Chinese population

AIMS

To evaluate the effects of TRAF6 and NLRX1 polymorphisms and their interactions with environmental factors on the susceptibility of type 2 diabetes mellitus (T2DM) vascular complications in a southern Han Chinese population.

METHODS

Five single nucleotide polymorphisms (SNPs) were genotyped in a case-control study to estimate risk factors of T2DM vascular complications. Gene-gene and gene-environment interactions and haplotype associations were also estimated.

RESULTS

The CA genotype of the NLRX1 rs4245191 was identified as a risk factor for T2DM macrovascular complications and diabetic cerebral infarction (OR=2.88, 95% CI=1.15-7.22, P=0.024; OR=4.00, 95% CI=1.04-15.38, P=0.043, respectively). A significantly lower T allele frequency in the TRAF6 rs16928973 was observed in T2DM patients with both microvascular and macrovascular complications compared with patients without any complication under the allelic model (T vs. C: OR=0.36, 95% CI=0.14-0.98, P=0.038). No significant differences in haplotypes, gene-gene interactions and gene-environment interactions were observed among T2DM vascular subgroup patients.

CONCLUSIONS

Our study provides evidence that the NLRX1 rs4245191 polymorphisms influence the risk of T2DM macrovascular complications and diabetic cerebral infarction.

Pain Catastrophizing and Anxiety are Associated With Heat Pain Perception in a Community Sample of Adults With Chronic Pain

BACKGROUND

The principle aim of this study was to investigate the associations between heat pain (HP) perception, pain catastrophizing, and pain-related anxiety in a heterogenous cohort of community-dwelling adults with chronic pain admitted to a 3-week outpatient pain rehabilitation program.

METHODS

All adults consecutively admitted to an outpatient pain rehabilitation program from July 2009 through January 2011 were eligible for study recruitment (n=574). Upon admission, patients completed the Pain Catastrophizing Scale (PCS), the short version of the Pain Anxiety Symptoms Scale (PASS-20), and HP perception was assessed using a standardized quantitative sensory testing (QST) method of levels.

RESULTS

Greater PCS scores were significantly correlated with lower standardized values of HP threshold (HP 0.5) (P=0.006) and tolerance (HP 5) (P=0.003). In a multiple variable model adjusted for demographic and clinical factors known to influence HP perception, every 10-point increase in the PCS was associated with a -0.124 point change in HP 0.5 (P=0.014) and a -0.142 change in HP 5 (P=0.014) indicating that participants with higher PCS scores had lower HP thresholds and tolerances, respectively. Similarly, greater PASS-20 scores significantly correlated with lower standardized values of HP 0.5 and HP 5. In a multiple variable model, every 10-point increase in the PASS-20 was associated with a -0.084 point change in HP 0.5 (P=0.005) and a -0.116 point change in HP 5 (P=0.001) indicating that participants with higher PASS-20 scores had lower HP thresholds and tolerances, respectively.

CONCLUSIONS

The findings of this study extend the use of a standardized method for assessing HP in a heterogenous sample of adults with chronic pain. Although pain catastrophizing shares significant variance with pain-related anxiety, our findings suggest that either measure would be appropriate for use in future studies that incorporate the QST method of levels.