Screening, diagnosis and management of diabetic sensorimotor polyneuropathy in clinical practice: International expert consensus recommendations

Correlations between distal sensorimotor polyneuropathy and cardiovascular complications in diabetic patients in the North-Eastern region of Hungary

Distal sensorimotor polyneuropathy (DSPN) is the earliest detectable and the most frequent microvascular complication in diabetes mellitus. Several studies have previously demonstrated correlations between cardiovascular risk factors in diabetic patients and independent risk factors for diabetic neuropathy. Our objective was to retrospectively analyze data from diabetic patients in the North-East region of Hungary who underwent neuropathy screening at the Diabetic Neuropathy Center, University of Debrecen, between 2017 and 2021. We aimed to investigate the correlations between cardiovascular risk factors and microvascular complications among patients with DSPN. The median age of the patients was 67 years, 59,6% were female, and 91,1% had type 2 diabetes. The prevalence of DSPN among the study subjects was 71.7%. A significantly longer duration of diabetes (p<0.01) was noted in patients with DSPN. Those with DSPN demonstrated a significantly higher HbA1c level (p<0.001) and a greater frequency of insulin use (p = 0.001). We observed a significantly elevated albumin/creatinine ratio (p<0.001) and a significantly lower eGFR (p<0.001) in patients with DSPN. Diabetic retinopathy exhibited a significantly higher prevalence in patients with DSPN (p<0.001). A higher prevalence of myocardial infarction (p<0.05), ischemic heart disease (p<0.001), peripheral arterial disease (p<0.05) and a history of atherosclerosis (p<0.05) was observed in patients with DSPN. In a multivariate logistic regression analysis, the following factors were independently associated with the presence of DSPN: higher HbA1c (OR:2.58, 95% CI:1.89-3.52, p<0.001), age (OR:1.03, 95% CI:1.01-1.05, p = 0.006), albumin/creatinine ratio above 3 mg/mmol (OR:1.23, 95% CI:1.06-1.45, p = 0.008), retinopathy (OR:6.06, 95% CI:1.33-27.53, p = 0.02), and composite cardiovascular endpoint (OR:1.95, 95% CI:1.19-3.19, p = 0.008). Our study revealed that age, elevated HbA1c levels, significant albuminuria, retinopathy, and cardiovascular complications may increase the risk of DSPN. Further investigation of these associations is necessary to understand the impact of patient characteristics during the treatment of diabetic neuropathy.

Association of transketolase polymorphisms with diabetic polyneuropathy in the general population: The KORA F4 study

AIMS

We recently reported that genetic variability in the TKT gene encoding transketolase, a key enzyme in the pentose phosphate pathway, is associated with measures of diabetic sensorimotor polyneuropathy (DSPN) in recent-onset diabetes. Here, we aimed to substantiate these findings in a population-based KORA F4 study.

MATERIALS AND METHODS

In this cross-sectional study, we assessed seven single nucleotide polymorphisms (SNPs) in the transketolase gene in 952 participants from the KORA F4 study with normal glucose tolerance (NGT; n = 394), prediabetes (n = 411), and type 2 diabetes (n = 147). DSPN was defined by the examination part of the Michigan Neuropathy Screening Instrument (MNSI) using the original MNSI > 2 cut-off and two alternative versions extended by touch/pressure perception (TPP) (MNSI > 3) and by TPP plus cold perception (MNSI > 4).

RESULTS

After adjustment for sex, age, BMI, and HbA1c, in type 2 diabetes participants, four out of seven transketolase SNPs were associated with DSPN for all three MNSI versions (all p ≤ 0.004). The odds ratios of these associations increased with extending the MNSI score, for example, OR (95% CI) for SNP rs62255988 with MNSI > 2: 1.99 (1.16-3.41), MNSI > 3: 2.27 (1.26-4.09), and MNSI > 4: 4.78 (2.22-10.26); SNP rs9284890 with MNSI > 2: 2.43 (1.42-4.16), MNSI > 3: 3.46 (1.82-6.59), and MNSI > 4: 4.75 (2.15-10.51). In contrast, no associations were found between transketolase SNPs and the three MNSI versions in the NGT and prediabetes groups.

CONCLUSIONS

The link of genetic variation in transketolase enzyme to diabetic polyneuropathy corroborated at the population level strengthens the concept suggesting an important role of pathways metabolising glycolytic intermediates in the evolution of diabetic polyneuropathy.

Expert opinion on screening, diagnosis and management of diabetic peripheral neuropathy: a multidisciplinary approach

The proposed expert opinion aimed to address the current knowledge on conceptual, clinical, and therapeutic aspects of diabetic peripheral neuropathy (DPN) and to provide a guidance document to assist clinicians for the best practice in DPN care. The participating experts consider the suspicion of the disease by clinicians as a key factor in early recognition and diagnosis, emphasizing an improved awareness of the disease by the first-admission or referring physicians. The proposed "screening and diagnostic" algorithm involves the consideration of DPN in a patient with prediabetes or diabetes who presents with neuropathic symptoms and/or signs of neuropathy in the presence of DPN risk factors, with careful consideration of laboratory testing to rule out other causes of distal symmetric peripheral neuropathy and referral for a detailed neurological work-up for a confirmative test of either small or large nerve fiber dysfunction in atypical cases. Although, the first-line interventions for DPN are currently represented by optimized glycemic control (mainly for type 1 diabetes) and multifactorial intervention (mainly for type 2 diabetes), there is a need for individualized pathogenesis-directed treatment approaches for DPN. Alpha-lipoic acid (ALA) seems to be an important first-line pathogenesis-directed agent, given that it is a direct and indirect antioxidant that works with a strategy targeted directly against reactive oxygen species and indirectly in favor of endogenous antioxidant capacity for improving DPN conditions. There is still a gap in existing research in the field, necessitating well-designed, robust, multicenter clinical trials with sensitive endpoints and standardized protocols to facilitate the diagnosis of DPN via a simple and effective algorithm and to track progression of disease and treatment response. Identification of biomarkers/predictors that would allow an individualized approach from a potentially disease-modifying perspective may provide opportunities for novel treatments that would be efficacious in early stages of DPN, and may modify the natural course of the disease. This expert opinion document is expected to increase awareness among physicians about conceptual, clinical, and therapeutic aspects of DPN and to assist them in timely recognition of DPN and translating this information into their clinical practice for best practice in the management of patients with DPN.

Current practice of podiatrists in testing for diabetic polyneuropathy and implementing foot care (PROTECT Study Survey 2)

AIMS

Podiatrists constitute a key member of a multidisciplinary foot care team, but their services remain underutilized. We sought to gain insights into the daily practice of podiatrists focusing on screening for and monitoring of diabetic sensorimotor polyneuropathy (DSPN) as well as foot management.

METHODS

This cross-sectional survey included 125 podiatrists from 12 federal states across Germany who responded to an online questionnaire.

RESULTS

The majority of patients treated in podiatry practices were referred by general practitioners and diabetologists. Screening for or follow-up of DSPN was performed by 36% of the respondents at least once a year, by 28% only at initial examination, by 21% only at suspicion, and by 10% basically at each treatment visit. Instruments to assess vibration, touch/pressure, and temperature sensation were used by 81-94% of the podiatrists. Previously undiagnosed DSPN and foot ulcers were detected frequently/very frequently (≥6 cases/month) by 24.0 and 18.4% of the podiatrists, respectively. Almost all podiatrists advised daily self-monitoring of feet and appropriate foot care and >50% gave advice on medical treatment.

CONCLUSIONS

Podiatrists play an important role in the detection, monitoring, and management of both DSPN and diabetic foot ulcers, suggesting that the utilization of their services should be fostered.

Contemporary prevalence of diabetic neuropathies in individuals with type 1 and type 2 diabetes in a Danish tertiary outpatient clinic

BACKGROUND

Population-based prevalence estimates of distal symmetric polyneuropathy (DPN) and diabetic autonomic neuropathy (DAN) are scares. Here we present neuropathy estimates and describe their overlap in a large cohort of people with type 1 and type 2 diabetes.

METHODS

In a large population of outpatient participants, DPN was assessed using vibration perception threshold, sural nerve function, touch, pain and thermal sensation. Definite DPN was defined by the Toronto Consensus Criteria. Painful DPN was defined by Douleur Neuropathique 4 Questions. DAN measures were: cardiovascular reflex tests, electrochemical skin conductance, and gastroparesis cardinal symptom index.

RESULTS

We included 822 individuals with type 1 (mean age (±SD) 54 ± 16 years, median [IQR] diabetes duration 26 [15-40] years) and 899 with type 2 diabetes (mean age 67 ± 11 years, median diabetes duration 16 [11-22] years). Definite DPN was prevalent in 54 % and 68 %, and painful DPN was in 5 % and 15 % of type 1 and type 2 participants, respectively. The prevalence of DAN varied between 6 and 39 % for type 1 and 9-49 % for type 2 diabetes. DPN without other neuropathy was present in 45 % with T1D and 50 % with T2D.

CONCLUSION

The prevalence of DPN and DAN was high. DPN and DAN co-existed in only 50 % of cases.

[Diagnostic workup for polyneuropathy]

Polyneuropathy is a disease of the peripheral nervous system that usually results in distally emphasized, often symmetrical sensory and motor stimulation and deficits. These are often extremely painful. They can be divided into hereditary and acquired causes; inflammatory and infectious causes should be further differentiated among the acquired causes. A careful diagnostic workup is essential. Clinical signs and distribution patterns of symptoms can often already provide clues to the underlying aetiology. This review describes this workup, which in addition to the medical history and clinical examination always includes thorough laboratory diagnostics, electrophysiological examination and cerebrospinal fluid diagnostics. In individual cases, further diagnostic steps may be necessary in order to make the correct diagnosis.

Clinical effects of combined use of carbamazepine and amitriptyline in the treatment of diabetic neuropathy with concurrent diabetic foot

OBJECTIVE

This study aims to analyze the clinical effects of combining carbamazepine and amitriptyline in the treatment of diabetic neuropathy with concurrent diabetic foot.

METHODS

A total of 120 diabetic neuropathy patients treated at our hospital from June 2022 to November 2023 were included in the study. Patients meeting the inclusion criteria were registered, and their basic data were collected. The patients were randomly divided into two groups: the control group treated with amitriptyline and the study group treated with a combination of carbamazepine and amitriptyline.

RESULTS

The study group demonstrated significantly better clinical efficacy compared to the control group (p < 0.05). There were no significant differences in psychological status and pain perception before treatment between the two groups (p > 0.05). However, post-treatment, the study group showed improved psychological status, reduced pain perception, and overall better quality of life in both physiological and psychological dimensions compared to the control group (p < 0.05).

CONCLUSION

The combined use of carbamazepine and amitriptyline in the treatment of diabetic neuropathy with concurrent diabetic foot yields positive clinical outcomes. It effectively alleviates symptoms, improves psychological well-being, reduces pain sensation, and enhances overall quality of life. These findings can guide physicians in adopting a more evidence-based treatment approach and provide patients with more effective individualized treatment strategies.

A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin

Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.

CVOT Summit Report 2023: new cardiovascular, kidney, and metabolic outcomes

The 9th Cardiovascular Outcome Trial (CVOT) Summit: Congress on Cardiovascular, Kidney, and Metabolic Outcomes was held virtually on November 30-December 1, 2023. This reference congress served as a platform for in-depth discussions and exchange on recently completed outcomes trials including dapagliflozin (DAPA-MI), semaglutide (SELECT and STEP-HFpEF) and bempedoic acid (CLEAR Outcomes), and the advances they represent in reducing the risk of major adverse cardiovascular events (MACE), improving metabolic outcomes, and treating obesity-related heart failure with preserved ejection fraction (HFpEF). A broad audience of endocrinologists, diabetologists, cardiologists, nephrologists and primary care physicians participated in online discussions on guideline updates for the management of cardiovascular disease (CVD) in diabetes, heart failure (HF) and chronic kidney disease (CKD); advances in the management of type 1 diabetes (T1D) and its comorbidities; advances in the management of CKD with SGLT2 inhibitors and non-steroidal mineralocorticoid receptor antagonists (nsMRAs); and advances in the treatment of obesity with GLP-1 and dual GIP/GLP-1 receptor agonists. The association of diabetes and obesity with nonalcoholic steatohepatitis (NASH; metabolic dysfunction-associated steatohepatitis, MASH) and cancer and possible treatments for these complications were also explored. It is generally assumed that treatment of chronic diseases is equally effective for all patients. However, as discussed at the Summit, this assumption may not be true. Therefore, it is important to enroll patients from diverse racial and ethnic groups in clinical trials and to analyze patient-reported outcomes to assess treatment efficacy, and to develop innovative approaches to tailor medications to those who benefit most with minimal side effects. Other keys to a successful management of diabetes and comorbidities, including dementia, entail the use of continuous glucose monitoring (CGM) technology and the implementation of appropriate patient-physician communication strategies. The 10th Cardiovascular Outcome Trial Summit will be held virtually on December 5-6, 2024 ( http://www.cvot.org ).

Update on Treating Painful Diabetic Peripheral Neuropathy: A Review of Current US Guidelines with a Focus on the Most Recently Approved Management Options

Painful diabetic peripheral neuropathy (DPN) is a highly prevalent and disabling complication of diabetes that is often misdiagnosed and undertreated. The management of painful DPN involves treating its underlying cause via lifestyle modifications and intensive glucose control, targeting its pathogenesis, and providing symptomatic pain relief, thereby improving patient function and health-related quality of life. Four pharmacologic options are currently approved by the US Food and Drug Administration (FDA) to treat painful DPN. These include three oral medications (duloxetine, pregabalin, and tapentadol extended release) and one topical agent (capsaicin 8% topical system). More recently, the FDA approved several spinal cord stimulation (SCS) devices to treat refractory painful DPN. Although not FDA-approved specifically to treat painful DPN, tricyclic antidepressants, serotonin/norepinephrine reuptake inhibitors, gabapentinoids, and sodium channel blockers are common first-line oral options in clinical practice. Other strategies may be used as part of individualized comprehensive pain management plans. This article provides an overview of the most recent US guidelines for managing painful DPN, with a focus on the two most recently approved treatment options (SCS and capsaicin 8% topical system), as well as evidence for using FDA-approved and guideline-supported drugs and devices. Also discussed are unmet needs for this patient population, and evidence for potential future treatments for painful DPN, including drugs with novel mechanisms of action, electrical stimulation devices, and nutraceuticals.

Analysis of depression incidence and influence factors among middle-aged and elderly diabetic patients in China: based on CHARLS data

BACKGROUND

To investigate the incidence of depression in middle-aged and elderly patients with diabetes in China and the influencing factors to provide a theoretical basis to improve the mental health of middle-aged and elderly patients with diabetes and formulate prevention, control, and intervention strategies.

METHODS

The sample of this study was obtained from the China Health and Aging Tracking Survey (CHARLS) 2018 survey data, and middle-aged and older patients with diabetes(responding "Yes" to the questionnaire: "Have you ever been told by a doctor that you have diabetes or elevated blood glucose [including abnormal glucose tolerance and elevated fasting glucose]?") aged ≥ 45 years were selected as study subjects (n = 2,613 ). Depressive symptoms of the study subjects were determined using the simplified version of the Depression Scale for Epidemiological Surveys scores(a score ≥ 10 was defined as depression), influence factors were analyzed using binary logistic regression, and proportion of depressive symptoms was standardized using the sex ratio of the seventh census.

RESULTS

Among the 2,613 middle-aged and elderly patients with diabetes, 1782 (68.2%) had depressive symptoms and 831 (31.8%) had no depressive symptoms. There were 481 (27.0%) patients aged 45-59 years, 978 (54.9%) aged 60-74 years, and 323 (18.1%) aged ≥ 75 years. The depression rate among middle-aged and elderly Chinese patients with diabetes after standardization correction was 67.5%. Binary logistic regression results showed that age, education level, life satisfaction, marital satisfaction, self-rated health grade, somatic pain, visual impairment, physical disability, and the presence of comorbid chronic diseases were factors that influenced the onset of depression in middle-aged and elderly Chinese patients with diabetes (P < 0.05).

CONCLUSION

According to a survey analysis of the CHARLS 2018 data, depression is influenced by a combination of factors among middle-aged and elderly patients with diabetes in China. Therefore, for this population, targeted prevention and control should be carried out for key populations, such as middle-aged and elderly people, poor physical health, and low life satisfaction and marital satisfaction, from various dimensions (e.g., demographic and sociological factors, physical health status, and life satisfaction and marital satisfaction).

Electroacupuncture efficacy in diabetic polyneuropathy: Study protocol for a double-blinded randomized controlled multicenter clinical trial

BACKGROUND

Diabetic peripheral neuropathy (DPN) is the most common complication of type 2 diabetes mellitus (T2DM); its diagnosis and treatment are based on symptomatic improvement. However, as pharmacological therapy causes multiple adverse effects, the implementation of acupunctural techniques, such as electroacupuncture (EA) has been suggested as an alternative treatment. Nonetheless, there is a lack of scientific evidence, and its mechanisms are still unclear. We present the design and methodology of a new clinical randomized trial, that investigates the effectiveness of EA for the treatment of DPN.

METHODS

This study is a four-armed, randomized, controlled, multicenter clinical trial (20-week intervention period, plus 12 weeks of follow-up after concluding intervention). A total of 48 T2DM patients with clinical signs and symptoms of DPN; and electrophysiological signs in the Nerve Conduction Study (NCS); will be treated by acupuncture specialists in outpatient units in Mexico City. Patients will be randomized in a 1:1 ratio to one of the following four groups: (a) short fibre DPN with EA, (b) short fibre DPN with sham EA, (c) axonal DPN with EA and (d) axonal DPN with sham EA treatment. The intervention will consist of 32 sessions, 20 min each, per patient over two cycles of intervention of 8 weeks each and a mid-term rest period of 4 weeks. The primary outcome will be NCS parameters, and secondary outcomes will include DPN-related symptoms and pain by Michigan Neuropathy Screening Instrument (MNSI), Michigan Diabetic Neuropathy Score (MDNS), Dolour Neuropatique Score (DN-4), Semmes-Westein monofilament, Numerical Rating Scale (NRS) for pain assessment, and the 36-item Short Form Health Survey (SF-36). To measure quality of life and improve oxidative stress, the inflammatory response; and genetic expression; will be analysed at the beginning and at the end of treatment.

DISCUSSION

This study will be conducted to compare the efficacy of EA versus sham EA combined with conventional diabetic and neuropathic treatments if needed. EA may improve NCS, neuropathic pain and symptoms, oxidative stress, inflammatory response, and genetic expression, and it could be considered a potential coadjutant treatment for the management of DPN with a possible remyelinating effect.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT05521737 Registered on 30 August 2022. International Clinical Trials Registry Platform (ICTRP) ISRCTN97391213 Registered on 26 September 2022 [2b].

Expert consensus guidelines for community pharmacists in the management of diabetic peripheral neuropathy with a combination of neurotropic B vitamins

This consensus guidance is for community pharmacists in diabetic peripheral neuropathy (DPN) management with a combination of neurotropic B vitamins. A multidisciplinary team including endocrinology, neurology, and pharmacy from Thailand discussed and aligned the practical scheme of DPN management in the community pharmacy setting, using the literature review and having face-to-face meeting. Five major statements have been endorsed as consensus recommendations for DPN care with strong acknowledgment. The aims of DPN management included reducing symptoms and the risk of complications, minimising adverse reactions from treatment regimens, and improving patients' knowledge and adherence to the treatment strategies. An initial screening process using a 7 items interview of Douleur Neuropathique 4 (DN4) questionnaire should be implemented to identify patients at risk of developing DPN. Subsequently, pharmacologic, and non-pharmacologic treatment should be employed based on patient-centered care. An interesting approach is combination of neurotropic B vitamins, which may be used as monotherapy or combination therapy to control DPN symptoms. The combined therapy potentially exhibits a synergistic effect and improves patient adherence. The consensus would be further considered in context of harmonisation of routine practice and country requirements.

Alpha-lipoic acid for diabetic peripheral neuropathy

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a frequent complication in people living with type 1 or type 2 diabetes. There is currently no effective treatment for DPN. Although alpha-lipoic acid (ALA, also known as thioctic acid) is widely used, there is no consensus about its benefits and harms.

OBJECTIVES

To assess the effects of alpha-lipoic acid as a disease-modifying agent in people with diabetic peripheral neuropathy.

SEARCH METHODS

On 11 September 2022, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and two clinical trials registers. We also searched the reference lists of the included studies and relevant review articles for additional references not identified by the electronic searches.

SELECTION CRITERIA

We included randomised clinical trials (RCTs) that compared ALA with placebo in adults (aged 18 years or older) and that applied the study interventions for at least six months. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. The primary outcome was change in neuropathy symptoms expressed as changes in the Total Symptom Score (TSS) at six months after randomisation. Secondary outcomes were change in neuropathy symptoms at six to 12 months and at 12 to 24 months, change in impairment, change in any validated quality of life total score, complications of DPN, and adverse events. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

Our analysis incorporated three trials involving 816 participants. Two studies included people with type 1 or type 2 diabetes, while one study included only people with type 2 diabetes. The duration of treatment was between six months and 48 months. We judged all studies at high risk of overall bias due to attrition. ALA compared with placebo probably has little or no effect on neuropathy symptoms measured by TSS (lower score is better) after six months (mean difference (MD) -0.16 points, 95% confidence interval (CI) -0.83 to 0.51; 1 study, 330 participants; moderate-certainty evidence). The CI of this effect estimate did not contain the minimal clinically important difference (MCID) of 0.97 points. ALA compared with placebo may have little or no effect on impairment measured by the Neuropathy Impairment Score-Lower Limbs (NIS-LL; lower score is better) after six months (MD -1.02 points, 95% CI -2.93 to 0.89; 1 study, 245 participants; low-certainty evidence). However, we cannot rule out a significant benefit, because the lower limit of the CI surpassed the MCID of 2 points. There is probably little or no difference between ALA and placebo in terms of adverse events leading to cessation of treatment within six months (risk ratio (RR) 1.48, 95% CI 0.50 to 4.35; 3 studies, 1090 participants; moderate-certainty evidence). No studies reported quality of life or complications associated with DPN.

AUTHORS' CONCLUSIONS

Our analysis suggests that ALA probably has little or no effect on neuropathy symptoms or adverse events at six months, and may have little or no effect on impairment at six months. All the studies were at high risk of attrition bias. Therefore, future RCTs should ensure complete follow-up and transparent reporting of any participants missing from the analyses.

Posterior Tibial Nerve Ultrasound Assessment of Peripheral Neuropathy in Adults with Type 2 Diabetes Mellitus

Background

Diabetic peripheral neuropathy (DPN) is a common and debilitating complication of type 2 diabetes mellitus (T2DM). Early detection and prompt institution of appropriate therapy could prevent undesirable outcomes such as paresthesia, pain, and amputation. Although the gold standard for diagnosing DPN is nerve conduction studies, high-resolution peripheral nerve ultrasonography may serve as a noninvasive and low-cost alternative for diagnosing and staging DPN. This study investigated the clinical utility of sonographic posterior tibial nerve cross-sectional area (PTN CSA) for diagnosing DPN in individuals with T2DM.

Methods

Eighty consecutive adults with T2DM and 80 age-/sex-matched controls were recruited. Clinical information was obtained, including symptoms, disease duration, Toronto clinical neuropathy score (TCNS), and biochemical parameters. The left PTN CSA at 1 cm, 3 cm, and 5 cm above the medial malleolus (MM) was measured with a high-frequency ultrasound transducer and compared to the detection of DPN using the TCNS.

Results

Based on the TCNS, 58 (72.5%) of the T2DM group had DPN. Of these, 14 (24.1%), 16 (27.6%), and 28 (48.3%) participants had mild, moderate, and severe DPN, respectively. All the mean PTN CSA (aggregate, 1 cm, 3 cm, and 5 cm above MM) of the participants with T2DM and DPN (T2DM-DPN) were significantly higher than those of T2DM without DPN (WDPN) and controls. All the PTN CSA increased significantly with increasing severity of DPN. The PTN CSA at 3 and 5 cm levels correlated weakly but significantly with fasting plasma glucose and glycated hemoglobin levels.

Conclusion

The PTN CSA is significantly larger in T2DM-DPN than in T2DM-WDPN and healthy controls. PTN ultrasonography can be an additional tool for screening DPN in patients with T2DM.

Behavior of neuropathy symptom score and neuropathy disability score in patients with and without peripheral diabetic neuropathy: A retrospective cohort study

BACKGROUND

This study aimed to stablish cut-off of early diagnosis of diabetic polyneuropathy (PDN) based on neuropathy symptom score (NSS) and neuropathy disability score (NDS); to determine the behavior of NDD and NDS in patients with and without PDN; and to verify the association between clinical and demographic variables with both tests.

METHODS

This retrospective cohort included 86 patients with diabetes. The NSS and NDS evaluations were collected in medical records in two moments: initial (entry into service) and final (after three years). Individuals were categorized in three groups: G1- PDN in both evaluations (N = 27); G2- PDN only in the final evaluation (N = 16); G3-individuals without PDN (N = 43). A ROC curve was performed to evaluate the sensitivity and specificity of NSS and NDS for PDN diagnosis. ANOVA was used to compare NSS and NDS between groups and evaluations, and multiple regression was performed to find predictors of PDN.

RESULTS

The NSS and NDS showed excellent sensitivity and specificity (NDS ≥1.5 and NSS ≥6.5) for PDN diagnosis. There was a significant difference between groups in initial (p = 0.000) and final (p = 0.000) NDS and NSS evaluations. There was an association between peripheral arterial disease (PAD) and increase in NSS (p = 0.024) in G2; and association between loss of protective sensation (LOPS) and increase in NSS in G3 (p < 0.001).

CONCLUSION

NSS and NDS tests showed excellent sensitivity and specificity for early PDN diagnosis. Behavior of both tests can differ patients with and without PDN. Furthermore, PAD and LOPS can be a predictor of PDN evolution.

Risk factors for peripheral artery disease and diabetic peripheral neuropathy among patients with type 2 diabetes

AIMS

To investigate the prevalence of peripheral artery disease (PAD) and diabetic peripheral neuropathy (DPN) and the associated risk factors among Chinese patients with type 2 diabetes mellitus.

METHODS

A cross-sectional study was conducted using data between November 1, 2018, and December 31, 2022. PAD was defined as ABI ≤ 0.9. DPN diagnosis involved specialized physician assessments using questionnaires and vibration perception threshold tests. Logistic regression analysis was used to identify related factors. We also evaluated the association between the clustering of risk factors and disease incidence.

RESULTS

The study population comprised 13,315 patients (mean age: 63.3 years). 4.9 % of the patients had PAD and 43.9 % had DPN. Multivariate regression analysis revealed advanced age, smoking, hypertension, coronary heart disease, dyslipidemia, elevated HbA1c, and uric acid levels as independent risk factors for PAD. For DPN, independent risk factors included advanced age, female gender, hypertension, coronary heart disease, elevated total cholesterol, triglycerides, lipoprotein(a), fasting plasma glucose, HbA1c, alkaline phosphatase, cystatin C, albumin-to-creatinine ratio, and elevated homocysteine levels, whereas apolipoprotein A was a protective factor. The clustering of risk factors was prevalent and associated with higher disease risk.

CONCLUSIONS

Our study contributed to identifying high-risk individuals and improving lower limb health among diabetic individuals.

A phase I study to evaluate the safety, tolerability, and pharmacokinetics of a novel, potent GABA analog HSK16149 in healthy Chinese subjects

Purpose: HSK16149 is a novel, potent gamma-aminobutyric acid (GABA) analog for the treatment of neuropathic pain. This study aimed to evaluate the safety, tolerability, and pharmacokinetics of HSK16149 after single and multiple doses in healthy Chinese subjects. Methods: The randomized, double-blind, placebo-controlled study comprised two parts: SAD (single ascending-dose study) and MAD (multiple ascending-dose study). A total of 122 healthy subjects were enrolled in this study. HSK16149 capsule or placebo was administered as the protocol required. The safety of the drug was evaluated through clinical examinations and adverse events. Blood and urine samples were collected at the designated time intervals for pharmacokinetic analysis. Results: Subjects were generally well tolerated after HSK16149 administration and the most common treatment-emergent adverse event (TEAEs) was dizziness, which was expected based on the mechanism of action of HSK16149. In SAD, AUC and Cmax were shown to have a dose-proportional relationship in the dose range of 5-120 mg. The t1/2 of HSK16149 is 3.7-6.4 h. In MAD, after a single and multiple administration of 15-80 mg, AUC and Cmax are proportional to the increased dose of HSK16149, and the accumulative ratios of AUC and Cmax at steady-state were 1.05-1.44 and 1.07-1.36, respectively, indicating that HSK16149 only accumulated slightly after repeated administration. Conclusion: HSK16149 was well tolerated in healthy Chinese subjects. Based on the safety and pharmacokinetic data, 80 mg twice daily (BID) was suggested as the highest target dose for further clinical development. Clinical Trial Registration: http://www.chinadrugtrials.org.cn, identifier CTR20182535 and CTR20191317.

Conventional management and current guidelines for painful diabetic neuropathy

Painful Diabetic Peripheral Neuropathy (PDN) is common, affecting around a quarter of patients with both type 1 and type 2 diabetes, and can lead to significant curtailment of functionality and quality of life. Patients may present with unremitting burning, aching or "electric-shock" type pains in their feet, legs and later, in the hands. Conventional management approaches must focus not only on pain relief, but also on concurrent sleep problems, mood disorders and functionality. The mainstay of treatment is pharmacotherapy. Most current international guidelines recommend a choice of four drugs: amitriptyline, duloxetine, pregabalin or gabapentin, as initial treatment for PDN. Recent evidence from the OPTION-DM trial demonstrated that these drugs and their combinations have equivalent efficacy. Moreover, combination treatment provided significant pain relief to patients with inadequate response to the maximum tolerated dose of monotherapy. PDN refractory to pharmacotherapy can be treated with capsaicin 8% or high frequency spinal cord stimulation.

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

BACKGROUND

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

AIM

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

PARTICIPANTS

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

EVIDENCE

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

CONSENSUS PROCESS

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

CONCLUSION

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

Real world outcomes with spinal cord stimulation

High frequency spinal cord stimulation (SCS) is a safe and effective treatment option for refractory painful diabetic neuropathy and should be considered for use early in the course of the disease. Raising awareness of this minimally invasive treatment option among physician networks is of major importance.

Pathogenetic treatments for diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is found in around one third of people with diabetes, but remains inadequately diagnosed and treated. Its management includes three cornerstones: 1) causal treatment with lifestyle modification, intensive diabetes therapy aimed at near-normoglycemia, and multifactorial cardiovascular risk intervention, 2) pathogenesis-oriented pharmacotherapy, and 3) symptomatic pain relief. Since symptomatic analgesic monotherapy only relieves the pain without targeting the underlying neuropathy and both has limited efficacy and is associated with adverse events, there is an unmet need for additional approaches derived from the pathogenetic concepts of DPN. Preclinical studies have suggested that diabetic neuropathy can be prevented or improved through the use of various agents that interfere with the pathophysiology of the underlying condition. Some of these encouraging findings could be translated successfully into the clinical setting. Efficacy and excellent safety were demonstrated in several meta-analyses (α-lipoic acid) and randomized clinical trials (benfotiamine, actovegin, epalrestat) in the treatment of symptomatic DPN. The NATHAN 1 trial demonstrated an improvement of neuropathic signs (deficits, impairments) after four years in asymptomatic DPN. These compounds are currently authorized for treatment of DPN in several countries. Long-term pivotal clinical trials should further establish their value as mono- and combination therapies in DPN.

Acupuncture for painful diabetic peripheral neuropathy: a systematic review and meta-analysis

Background

Painful Diabetic Peripheral Neuropathy (PDPN) is a common complication of diabetes, it severely affects the quality of life of patients. Acupuncture has been shown to be effective in the treatment of PDPN. To evaluate the efficacy and safety of acupuncture for pain relief in patients diagnosed with diabetic peripheral neuropathy, we conducted a systematic review and meta-analysis.

Method

We thoroughly searched specific databases, which included PUBMED, EMBASE, Web of Science, the Cochrane Library, the Chinese Biomedical Literature Database, the Chinese National Knowledge Infrastructure, China Science and Technology Journal Database and the Wanfang Data. All randomized controlled trials of acupuncture therapy for PDPN with pain change scales were included. Included studies were assessed for methodological quality according to the risk of bias from the Cochrane handbook. Meta-analyses were carried out to analyze the outcomes, subgroup analyses, sensitivity analyses, and funnel plot analyses were undertaken.

Results

This systematic review evaluated a total of 25 trials of acupuncture therapy in combination with conventional treatment, involving a total of 1,561 patients with PDPN. According to the results, among 16 trials using VAS scores with a total of 1,552 patients, 2 acupoint injection trials (MD -2.38, 95% CI: -2.76 to -2.01, p < 0.00001), 12 acupuncture trials (MD -1. 31, 95% CI: -1.60 to -1.02, p < 0.00001) and 2 moxibustion trials showed that acupuncture therapy combined with conventional treatment improved pain better than conventional treatment (MD -2.50, 95% CI: -2.76 to -2.24, p < 0.00001). In the subgroup analysis of the acupuncture group, the results of the 5 trials in which the location of acupuncture was only in the limbs (MD -1.27, 95% CI: -1.54 to -1.01, p < 0.00001) and the 7 trials both in limbs and torso (MD -1.38, 95% CI: -1.81 to -0.95, p < 0.00001) also demonstrated that acupuncture was effective in pain improvement.

Conclusion

This meta-analysis analyzed the possible efficacy of acupuncture in combination with conventional treatment for pain in diabetic peripheral neuropathy, particularly when acupoints are located in the limbs. However, there are limitations to this meta-analysis and future clinical studies are needed to confirm these findings.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023449447, identifier (CRD42023449447).

Declining Incidence Rates of Distal Symmetric Polyneuropathy in People With Type 1 and Type 2 Diabetes in Denmark, With Indications of Distinct Patterns in Type 1 Diabetes

OBJECTIVE

It is not known if incidence rates for diabetic distal symmetric polyneuropathy (DSPN) are decreasing, as they are for other diabetic complications. Here, we investigated incidence rates of DSPN in type 1 and type 2 diabetes in a large population-based study.

RESEARCH DESIGN AND METHODS

In the period 1996 to 2018, 19,342 individuals were identified at a Danish tertiary diabetes center. Vibration perception threshold was assessed by biothesiometry and repeated throughout the study. Exclusion of prevalent DSPN cases or missing data left data on 9,473 individuals for analysis of DSPN using a cutoff of >25 V and on 2,783 individuals for analysis using an age-, sex-, and height-specific cutoff. Poisson regression analysis was used to model incidence rates of DSPN for both cutoff types and separately for diabetes types. Covariates were sex, age, diabetes duration, and calendar time.

RESULTS

Incidence rates (95% CI) of DSPN decreased from 1996 to 2018 (e.g., from 4.78 [3.60-6.33]/100 person-years [PY] to 1.15 [0.91-1.47]/100 PY for 40-year-old men with type 1 diabetes and from 16.54 [11.80-23.18]/100 PY to 8.02 [6.63-9.69]/100 PY for 60-year-old men with type 2 diabetes, when using >25 V as the cutoff value). Analyses using age-, sex-, and height-specific cutoff values demonstrated similar incidence patterns by calendar time without sex differences. For type 1 diabetes, decreasing incidence rates were seen with older age.

CONCLUSIONS

Incidence rates for DSPN are declining in type 1 and type 2 diabetes, possibly due to improved diabetes treatment. This causality remains to be explored. Distinct age-related patterns indicate that the pathophysiology of DSPN may differ between diabetes types.

Novel therapeutical approaches based on neurobiological and genetic strategies for diabetic polyneuropathy - A review

BACKGROUND

Neuropathy is among the most often reported consequences of diabetes and the biggest cause of morbidity and mortality in people suffering from this life-long disease. Although different therapeutic methods are available for diabetic neuropathy, it is still the leading cause of limb amputations, and it significantly decreases patients' quality of life.

AIM

This study investigates potential novel therapeutic options that could ameliorate symptoms of DN.

METHODOLOGY

Research and review papers from the last 10 years were taken into consideration.

RESULTS

There are various traditional drugs and non-pharmacological methods used to treat this health condition. However, the research in the area of pathogenic-oriented drugs in the treatment of DN showed no recent breakthroughs, mostly due to the limited evidence about their effectiveness and safety obtained through clinical trials. Consequently, there is an urgent demand for the development of novel therapeutic options for diabetic neuropathy.

CONCLUSION

Some of the latest novel diagnostic methods for diagnosing diabetic neuropathy are discussed as well as the new therapeutic approaches, such as the fusion of neuronal cells with stem cells, targeting gene delivery and novel drugs.

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.

Examination of Lower Limb Microcirculation in Diabetic Patients with and without Intermittent Claudication

Intermittent claudication is a frequent complaint in lower extremity artery disease, but approximately two thirds of patients are asymptomatic, most of which are diabetic patients. Non-invasive angiological and microrheological tests on diabetic subjects with and without intermittent claudication were performed in the present study. In total, 98 diabetic patients were included and divided into two groups: 20 patients (63.5 ± 8.8 years, 55% men, 45% women) had intermittent claudication, 78 patients (65.5 ± 9.3 years, 61.5% men, 38.5% women) were asymptomatic. Hand-held Doppler ultrasound examination, transcutaneous tissue partial oxygen pressure (tcpO2) measurement, Rydel-Seiffer tuning fork tests, and 6-min walk tests were performed, and erythrocyte aggregation was investigated. Ankle-brachial index (p < 0.02) and tcpO2, measured during provocation tests (p < 0.003) and the 6-min walk test (p < 0.0001), significantly deteriorated in the symptomatic group. A higher erythrocyte aggregation index and faster aggregate formation was observed in claudication patients (p < 0.02). Despite the statistically better results of the asymptomatic group, 13% of these patients had severe limb ischemia based on the results of tcpO2 measurement. Claudication can be associated with worse hemodynamic and hemorheological conditions in diabetic patients; however, severe ischemia can also develop in asymptomatic subjects. Non-invasive vascular tests can detect ischemia, which highlights the importance of early instrumental screening of the lower limbs.

Evidence of impaired H-reflex and H-reflex rate-dependent depression in diabetes, prediabetes and obesity: a mini-review

Diabetes Mellitus is a public health problem associated with complications such as neuropathy; however, it has been proposed that these may begin to develop during prediabetes and may also be present in persons with obesity. Diabetic peripheral neuropathy is the presence of signs and/or symptoms of peripheral nerve dysfunction in people living with diabetes, which increases the risk of developing complications and has a deleterious impact on quality of life. As part of the therapeutic protocol for diabetes, screening tests to identify peripheral neuropathy are suggested, however, there are no recommendations for people with prediabetes and obesity without symptoms such as pain, numbness, or paresthesias. Moreover, clinical screening tests that are usually used to recognize this alteration, such as tendon reflex, temperature sensation, and pressure and vibration perception, might be subjective as they depend on the evaluator's experience thus the incorrect application of these tests may not recognize the damage to small or large-nerve fibers. Recent evidence suggests that an objective study such as the impairment of the rate-dependent depression of the H-reflex could be used as a biomarker of spinal disinhibition and hence may provide more information on sensorimotor integration.

Effect of static magnetic field therapy on diabetic neuropathy and quality of life: a double-blind, randomized trial

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus (DM) that can cause annoying symptoms. To address this condition, several treatment approaches have been proposed, including static magnetic field (SMF) therapy, which has shown promise in treating neurological conditions. Therefore, this study aimed to investigate the effects of SMF therapy on symptomatic DPN and the quality of life (QoL) in patients with type 2 diabetes.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted from April to October 2021. Sixty-four DPN patients (20 males, 44 females) were recruited for the study via invitation. The participants were divided into two groups: the magnet group, which used magnetic ankle bracelets (155 mT) for 12 weeks, and the sham group, which used non-magnetic ankle bracelets for the same duration. Neuropathy Symptom Score (NSS), Neuropathic Disability Score (NDS), and Visual Analogue Scale (VAS) were used to assess neuropathy symptoms and pain. In addition, the Neuropathy Specific Quality of Life Questionnaire (Neuro-QoL) tool was used to measure the patients' quality of life.

RESULTS

Before treatment, there were no significant differences between the magnet and sham groups in terms of the NSS scores (P = 0.50), NDS scores (P = 0.74), VAS scores (P = 0.17), and Neuro-QoL scores (P = 0.82). However, after 12 weeks of treatment, the SMF exposure group showed a significant reduction in NSS scores (P < 0.001), NDS scores (P < 0.001), VAS scores (P < 0.001), and Neuro-QoL scores (P < 0.001) compared to the baseline. The changes in the sham group, on the other hand, were not significant.

CONCLUSION

According to obtained data, SMF therapy is recommended as an easy-to-use and drug-free method for reducing DPN symptoms and improving QoL in diabetic type-2 patients. Trial registration Registered at Iranian Registry of Clinical Trials: IRCT20210315050706N1, 2021/03/16.

Serum Isthmin-1 Was Increased in Type 2 Diabetic Patients but Not in Diabetic Sensorimotor Peripheral Neuropathy

Purpose

This study aimed to investigate the relationship between serum isthmin-1 (ISM1) and type 2 diabetes mellitus (T2DM), and the alteration of serum ISM1 level in both diabetic sensorimotor peripheral neuropathy (DSPN) and diabetic adults with obesity.

Patients and Methods

We recruited 180 participants (120 T2DM and 60 controls) in the cross-sectional study. First, we compared the serum ISM1 concentration in diabetic patients and non-diabetic controls. Secondly, according to DSPN, patients were divided into DSPN and non-DSPN groups. Last, patients were categorized as lean T2DM (15 males, 15 females), overweight T2DM (35 males, 19 females), and obese T2DM groups (23 males, 13 females) according to gender and body mass index (BMI). All participants were collected with clinical characteristics and biochemical profiles. Serum ISM1 was detected in all subjects by ELISA.

Results

Higher serum ISM1 [7.78 ng/mL (IQR: 6.33-9.06) vs 5.22 (3.86-6.04), P <0.001] was observed in diabetic patients compared to non-diabetic controls. Binary logistic regression analysis showed that serum ISM1 was a risk factor for type 2 diabetes after adjustment (OR=4.218, 95% CI: 1.843-9.653, P=0.001). Compared to the non-DSPN group, serum ISM1 level was not changed significantly in patients who suffered from DSPN. Diabetic females with obesity had lower level of serum ISM1 (7.10±1.29 ng/mL) when compared to the lean T2DM (8.42±1.36 ng/mL, P <0.05) and the overweight T2DM (8.33±1.27 ng/mL, P <0.05). However, serum ISM1 was not changed significantly in male groups or all patients together.

Conclusion

Serum ISM1 was a risk factor for type 2 diabetes, and it was associated with diabetic adults with obesity while there was sexual dimorphism. However, serum ISM1 levels were not correlated with DSPN.

Chemoproteomic target deconvolution reveals Histone Deacetylases as targets of (R)-lipoic acid

Lipoic acid is an essential enzyme cofactor in central metabolic pathways. Due to its claimed antioxidant properties, racemic (R/S)-lipoic acid is used as a food supplement but is also investigated as a pharmaceutical in over 180 clinical trials covering a broad range of diseases. Moreover, (R/S)-lipoic acid is an approved drug for the treatment of diabetic neuropathy. However, its mechanism of action remains elusive. Here, we performed chemoproteomics-aided target deconvolution of lipoic acid and its active close analog lipoamide. We find that histone deacetylases HDAC1, HDAC2, HDAC3, HDAC6, HDAC8, and HDAC10 are molecular targets of the reduced form of lipoic acid and lipoamide. Importantly, only the naturally occurring (R)-enantiomer inhibits HDACs at physiologically relevant concentrations and leads to hyperacetylation of HDAC substrates. The inhibition of HDACs by (R)-lipoic acid and lipoamide explain why both compounds prevent stress granule formation in cells and may also provide a molecular rationale for many other phenotypic effects elicited by lipoic acid.

Painful Diabetic Peripheral Neuropathy: Practical Guidance and Challenges for Clinical Management

Painful diabetic peripheral neuropathy (PDPN) is present in nearly a quarter of people with diabetes. It is estimated to affect over 100 million people worldwide. PDPN is associated with impaired daily functioning, depression, sleep disturbance, financial instability, and a decreased quality of life. Despite its high prevalence and significant health burden, it remains an underdiagnosed and undertreated condition. PDPN is a complex pain phenomenon with the experience of pain associated with and exacerbated by poor sleep and low mood. A holistic approach to patient-centred care alongside the pharmacological therapy is required to maximise benefit. A key treatment challenge is managing patient expectation, as a good outcome from treatment is defined as a reduction in pain of 30-50%, with a complete pain-free outcome being rare. The future for the treatment of PDPN holds promise, despite a 20-year void in the licensing of new analgesic agents for neuropathic pain. There are over 50 new molecular entities reaching clinical development and several demonstrating benefit in early-stage clinical trials. We review the current approaches to its diagnosis, the tools, and questionnaires available to clinicians, international guidance on PDPN management, and existing pharmacological and non-pharmacological treatment options. We synthesise evidence and the guidance from the American Association of Clinical Endocrinology, American Academy of Neurology, American Diabetes Association, Diabetes Canada, German Diabetes Association, and the International Diabetes Federation into a practical guide to the treatment of PDPN and highlight the need for future research into mechanistic-based treatments in order to prioritise the development of personalised medicine.

Morbidity and mortality of patients with diabetic neuropathy treated with pathogenetically oriented alpha-lipoic acid versus symptomatic pharmacotherapies - a nationwide database analysis from Hungary

AIMS

Diabetic neuropathy is associated with increased risk of morbidity and all-cause mortality. It is unclear whether these outcomes differ in patients with diabetic neuropathy treated with pathogenetically oriented vs symptomatic pharmacotherapies.

METHODS

We performed a retrospective (2009-2019) database analysis of patients treated with pathogenetically oriented alpha-lipoic acid (ALA) or symptomatic pharmacotherapies for diabetic neuropathy. We investigated clinical outcomes in propensity score matched patients in Hungary. Changes in hazard ratios and annualized event rates were assessed and sensitivity analyses performed.

RESULTS

Hazard ratios favored treatment with ALA vs symptomatic pharmacotherapies regarding acute myocardial infarction (HR 0.73, 95%CI: 0.60-0.89, p = 0.0016), stroke (HR 0.71, 95%CI: 0.62-0.82, p<0.0001), hospitalization for heart failure (HR 0.72, 95%CI: 0.66-0.78, p<0.0001), cancer events (HR 0.83, 95% CI: 0.76-0.92, p = 0.0002) and all-cause mortality (HR 0.55, 95% CI: 0.49-0.61, p<0.0001), but not for lower limb amputation (HR 1.05, 95%CI: 0.89-1.25, p = 0.5455). This association was supported by results of evaluating annual event rates and sensitivity analyses.

CONCLUSIONS

This retrospective database analysis revealed a lower occurrence of cardio- and cerebrovascular morbidity, cancer events and all-cause mortality in patients with diabetic neuropathy treated with pathogenetically oriented ALA vs symptomatic pharmacotherapies. This hypothesis-generating result requires further investigations.

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.

A randomized, active-controlled, parallel, open-label, multicenter, phase 4 study to compare the efficacy and safety of pregabalin sustained release tablet and pregabalin immediate release capsule in type II diabetic patients with peripheral neuropathic pain

BACKGROUND

Diabetic peripheral polyneuropathy is the most common chronic complication of type 2 diabetes. Neuropathic pain is challenging to manage, and various drugs are required to control it, decreasing treatment adherence. Pregabalin, a ligand that binds to alpha-2-delta subunits of the presynaptic calcium channel, has been approved by the Food and Drug Administration for the treatment of diabetic neuropathic pain. In this study, we will compare the efficacy, safety, treatment satisfaction, and compliance between pregabalin sustained-release (SR) tablets and pregabalin immediate-release (IR) capsules in type 2 diabetic patients with peripheral neuropathic pain.

METHODS

This study is a randomized, active-controlled, parallel, open-label, multicenter, phase 4 clinical trial (trial registration NCT05624853). Type 2 diabetic patients with glycosylated hemoglobin below 10% and peripheral neuropathic pain who have been taking pregabalin 150 mg/d or more for more than 4 weeks will be randomly assigned to pregabalin SR tablet (150 mg once a day, n = 65) or pregabalin IR capsule (75 mg twice a day, n = 65) therapy for 8 weeks. The primary outcome will be the efficacy of SR pregabalin after 8 weeks of treatment, which will be assessed by visual analog scale measurements. The secondary outcomes will include changes in several parameters, such as quality of life, treatment satisfaction, quality of sleep, and drug compliance.

DISCUSSION

In thus study, we aim to demonstrate that pregabalin SR tablets are associated with better compliance and satisfaction compared with pregabalin IR capsules, despite similar efficacy.

Screening for diabetic peripheral neuropathy in resource-limited settings

BACKGROUND

Diabetic neuropathy is the most common microvascular complication of diabetes mellitus and a major risk factor for diabetes-related lower-extremity complications. Diffuse neuropathy is the most frequently encountered pattern of neurological dysfunction and presents clinically as distal symmetrical sensorimotor polyneuropathy. Due to the increasing public health significance of diabetes mellitus and its complications, screening for diabetic peripheral neuropathy is essential. Consequently, a review of the principles that guide screening practices, especially in resource-limited clinical settings, is urgently needed.

MAIN BODY

Numerous evidence-based assessments are used to detect diabetic peripheral neuropathy. In accordance with current guideline recommendations from the American Diabetes Association, International Diabetes Federation, International Working Group on the Diabetic Foot, and National Institute for Health and Care Excellence, a screening algorithm for diabetic peripheral neuropathy based on multiphasic clinical assessment, stratification according to risk of developing diabetic foot syndrome, individualized treatment, and scheduled follow-up is suggested for use in resource-limited settings.

CONCLUSIONS

Screening for diabetic peripheral neuropathy in resource-limited settings requires a practical and comprehensive approach in order to promptly identify affected individuals. The principles of screening for diabetic peripheral neuropathy are: multiphasic approach, risk stratification, individualized treatment, and scheduled follow-up. Regular screening for diabetes-related foot disease using simple clinical assessments may improve patient outcomes.

Serum neurofilament light chain: a novel biomarker for early diabetic sensorimotor polyneuropathy

AIMS/HYPOTHESIS

No established blood-based biomarker exists to monitor diabetic sensorimotor polyneuropathy (DSPN) and evaluate treatment response. The neurofilament light chain (NFL), a blood biomarker of neuroaxonal damage in several neurodegenerative diseases, represents a potential biomarker for DSPN. We hypothesised that higher serum NFL levels are associated with prevalent DSPN and nerve dysfunction in individuals recently diagnosed with diabetes.

METHODS

This cross-sectional study included 423 adults with type 1 and type 2 diabetes and known diabetes duration of less than 1 year from the prospective observational German Diabetes Study cohort. NFL was measured in serum samples of fasting participants in a multiplex approach using proximity extension assay technology. DSPN was assessed by neurological examination, nerve conduction studies and quantitative sensory testing. Associations of serum NFL with DSPN (defined according to the Toronto Consensus criteria) were estimated using Poisson regression, while multivariable linear and quantile regression models were used to assess associations with nerve function measures. In exploratory analyses, other biomarkers in the multiplex panel were also analysed similarly to NFL.

RESULTS

DSPN was found in 16% of the study sample. Serum NFL levels increased with age. After adjustment for age, sex, waist circumference, height, HbA_1c, known diabetes duration, diabetes type, cholesterol, eGFR, hypertension, CVD, use of lipid-lowering drugs and use of non-steroidal anti-inflammatory drugs, higher serum NFL levels were associated with DSPN (RR [95% CI] per 1-normalised protein expression increase, 1.92 [1.50, 2.45], p<0.0001), slower motor (all p<0.0001) and sensory (all p≤0.03) nerve conduction velocities, lower sural sensory nerve action potential (p=0.0004) and higher thermal detection threshold to warm stimuli (p=0.023 and p=0.004 for hand and foot, respectively). There was no evidence for associations between other neurological biomarkers and DSPN or nerve function measures.

CONCLUSIONS/INTERPRETATION

Our findings in individuals recently diagnosed with diabetes provide new evidence associating higher serum NFL levels with DSPN and peripheral nerve dysfunction. The present study advocates NFL as a potential biomarker for DSPN.

Effects of 1-methyl-1, 2, 3, 4-tetrahydroisoquinoline on a diabetic neuropathic pain model

Background: Neuropathy is a prevalent and debilitating complication of poorly managed diabetes, contributing towards poor quality of life, amputation risk, and increased mortality. The available therapies for diabetic neuropathic pain (DPN) have limitations in terms of efficacy, tolerability and patient compliance. Dysfunction in the peripheral and central monoaminergic system has been evidenced in various types of neuropathic and acute pain. The objective of the present study was to investigate 1-methyl 1, 2, 3, 4-tetrahydroisoquinoline (1MeTIQ), an endogenous amine found in human brain with a known neuroprotective profile, in a model of streptozotocin (STZ) induced neuropathic pain. Methods: Diabetic neuropathy in male BALB/c mice was induced by intraperitoneal injection of a single dose of STZ (200 mg/kg). Upon development of DPN after 4 weeks, mice were investigated for mechanical allodynia (von Frey filament pressure test) and thermal hyperalgesia (tail immersion test). Ondansetron (1.0 mg/kg i.p.), naloxone (3.0 mg/kg i.p.) and yohimbine (2.0 mg/kg i.p.) were used to elucidate the possible mechanism involved. Postmortem frontal cortical, striatal and hippocampal tissues were dissected and evaluated for changes in levels of dopamine, noradrenaline and serotonin using High-Performance Liquid Chromatography (HPLC) with UV detection. Results: Acute administration of 1MeTIQ (15-45 mg/kg i.p.) reversed streptozotocin-induced diabetic neuropathic static mechanical allodynia (von Frey filament pressure test) and thermal hyperalgesia (tail immersion test), these outcomes being comparable to standard gabapentin. Furthermore, HPLC analysis revealed that STZ-diabetic mice expressed lower concentrations of serotonin in all three brain regions examined, while dopamine was diminished in the striatum and 1MeTIQ reversed all these neurotransmitter modifications. These findings suggest that the antihyperalgesic/antiallodynic activity of 1MeTIQ may be mediated in part via supraspinal opioidergic and monoaminergic modulation since they were naloxone, yohimbine and ondansetron reversible. Conclusion: It was also concluded that acute treatment with 1MeTIQ ameliorated STZ-induced mechanical allodynia and thermal hyperalgesia and restored brain regionally altered serotonin and dopamine concentrations which signify a potential for 1MeTIQ in the management of DPN.

The 8-Week Efficacy of Frequency Rhythmic Electrical Modulated System (FREMS) as an Add-on Therapy in the Treatment of Symptomatic Diabetic Peripheral Polyneuropathy

BACKGROUND

Frequency Rhythmic Electrical Modulated System (FREMS) is a method of transcutaneous treatment based on frequency-modulated electromagnetic neural stimulation. Its efficacy in neuropathic pain in diabetes mellitus still lacks enough research.

METHODS

A randomized, single-blind, sham-controlled trial in individuals with symmetric distal polyneuropathy (SDPN) as an add-on therapy compared to standard therapy with alpha-lipoic acid. Participants were randomized to FREMS and standard of care (SOC) versus SOC only. The primary outcome was a change from baseline in perceived pain assessed by visual analogue scale (VAS) after 5 days of treatment and after 8 weeks of follow-up between treatment groups.

RESULTS

After 5 days of treatment, patients in both groups felt significant reduction in pain as measured by VAS, although only FREMS treatment lasted for 8 weeks and induced a significant improvement in quality of life measured by EuroQol 5-Dimension 5-Level (EQ-5D-5L) and Clinical Global Impression of Change (CGI-C) questionnaires. There were non-significant differences observed in the instrument pain assessment. No relevant side effects were recorded during the study.

CONCLUSIONS

FREMS as an addition to alpha-lipoic acid therapy occurred to be a beneficial method of treatment in individuals with SDPN and was associated with improvements in pain severity, quality of life and clinical global improvement.

Distal symmetrical polyneuropathy is present in all individuals with diabetes and foot ulcers - and does not associate with healing time

We estimated the occurrence of diabetic neuropathy using six different diagnostic modalities in individuals with newly diagnosed diabetic foot ulcers (DFUs) and assessed the association with DFU healing time. All individuals with DFU had distal symmetrical polyneuropathy. Presence of neuropathy did not associate with ulcer healing time (p ≥ 0.12).

Screening and diagnosis of diabetic polyneuropathy in clinical practice: A survey among German physicians (PROTECT Study Survey)

AIMS

We sought to obtain detailed information on the procedures and appraisal of screening for and diagnosing diabetic sensorimotor polyneuropathy (DSPN) in clinical practice.

METHODS

This cross-sectional survey included 574 physicians from 13 federal states across Germany who responded to a tripartite questionnaire.

RESULTS

The vast majority of the respondents reported to screen for DSPN at least once a year (87 %), while 65 % reported to examine the feet of DSPN patients at least twice a year. However, only 28 % and 20 % of the respondents used questionnaires and scores to assess the severity of neuropathic symptoms and signs, respectively. The rates of participants reporting that they do not use a standardized testing procedure were 58 % for pressure sensation, 62 % for pain sensation, and 54 % for thermal sensation. The rates of respondents reporting that they do not deploy a standardized assessment were 41 % for vibration sensation, 73 % for pressure sensation, 77 % for pain sensation, and 66 % for thermal sensation. Half of the physicians oriented themselves towards clinical guidelines when diagnosing DSPN.

CONCLUSIONS

Despite relatively high screening rates, the willingness to implement both standardized testing procedures and assessment and to follow guidelines is low among physicians when screening for and clinically diagnosing DSPN.

Painful diabetic peripheral neuropathy: real-world comparison between topical treatment with lidocaine 700 mg medicated plaster and oral treatments

INTRODUCTION

Painful diabetic peripheral neuropathy (PDPN), a common complication of diabetes mellitus, is challenging to treat. Efficacy and tolerability of the topical lidocaine 700 mg medicated plaster (LMP) and well-established first-line oral medications (OM) were compared in refractory PDPN patients.

RESEARCH DESIGN AND METHODS

This is a subgroup analysis of a non-interventional, retrospective 24-week cohort study using anonymized routine medical care data from the German Pain eRegistry. Propensity score matching provided 732 datasets per treatment group. Primary effectiveness endpoint was the absolute change in average 24-hour Pain Intensity Index (0-100 mm) from baseline after 4, 12 and 24 weeks of treatment and over the entire treatment period.

RESULTS

The majority of this multimorbid and polymedicated study population of patients with PDPN had suffered pain for more than a year and presented with a high pain burden despite a median of seven previous analgesic medications. LMP treatment resulted in significant reductions in pain intensity and improvements in daily functioning already after 4 treatment weeks. Effectiveness was maintained over the treatment period even when concomitant analgesics were reduced or discontinued and quality of life improved. Mean change in the primary effectiveness parameter over the 24-week treatment period was -30.2 mm (SE 0.38) and -17.0 mm (SE 0.51) in the LMP and OM groups, respectively. Improvements in all effectiveness parameters were significantly greater under LMP than under OM treatment (p&lt;0.001). Significantly fewer patients under LMP than OM experienced drug-related adverse events (DRAEs; 9.6% vs 61.6%, p&lt;0.001) and discontinued treatment due to DRAEs (4.4% vs 35.8%, p&lt;0.001).

CONCLUSIONS

LMP was effective and well tolerated in routine clinical care of patients with PDPN. The more favorable benefit/risk profile and greater reduction in intake of concomitant analgesics compared with OM suggest LMP as a useful treatment option for PDPN.

TRIAL REGISTRATION NUMBER

EUPAS 32826.

Reversing painful and non-painful diabetic neuropathy with the capsaicin 8% patch: Clinical evidence for pain relief and restoration of function via nerve fiber regeneration

Introduction

Current oral treatments for pain in diabetic peripheral neuropathy (DPN) do not affect the progression of DPN i.e., "disease modification." We assessed whether Capsaicin 8% patch treatment can provide pain relief and also restore nerve density and function via nerve regeneration, in both painful (PDPN) and non-painful (NPDPN) diabetic peripheral neuropathy.

Methods

50 participants with PDPN were randomized to receive Capsaicin 8% patch Qutenza with Standard of Care (SOC) (PDPN Q+SOC group), or SOC alone (PDPN SOC group). Pain symptoms were assessed with a diary (Numerical Pain Rating Scale, NRPS) and questionnaires. Investigations included quantitative sensory testing (QST) and distal calf skin biopsies, at baseline and 3 months after baseline visit; subsequent options were 3-monthly visits over 1 year. 25 participants with NPDPN had tests at baseline, and 3 months after all received Capsaicin 8% patch treatment.

Results

At 3 months after baseline, PDPN Q+SOC group had reduction in NPRS score (p = 0.0001), but not PDPN SOC group. Short-Form McGill Pain Questionnaire (SF-MPQ) showed significant reductions in scores for overall and other pain descriptors only in the PDPN Q+SOC group. Warm perception thresholds were significantly improved only in the PDPN Q+SOC group (p = 0.02), and correlated with reduction in SF-MPQ overall pain score (p = 0.04). NPDPN Q+SOC group did not report pain during the entire study. Density of intra-epidermal nerve fibers (IENF) with PGP9.5 was increased at 3 months in PDPN Q+SOC (p = 0.0002) and NPDPN Q+SOC (p = 0.002) groups, but not in the PDPN SOC group. Increased sub-epidermal nerve fibers (SENF) were observed with GAP43 (marker of regenerating nerve fibers) only in PDPN Q+SOC (p = 0.003) and NPDPN Q+SOC (p = 0.0005) groups. Pain relief in the PDPN Q+SOC group was correlated with the increased PGP9.5 IENF (p = 0.0008) and GAP43 (p = 0.004), whereas those with lack of pain relief showed no such increase; in some subjects pain relief and increased nerve fibers persisted over months. PGP9.5 IENF increase correlated with axon-reflex vasodilatation in a NPDPN Q+SOC subset (p = 0.006).

Conclusions

Capsaicin 8% patch can provide pain relief via nerve regeneration and restoration of function in DPN (disease modification). It may thereby potentially prevent diabetic foot complications, including ulcers.

A Nomogram for Predicting the Possibility of Peripheral Neuropathy in Patients with Type 2 Diabetes Mellitus

Background and Purpose: Diabetic peripheral neuropathy (DPN) leads to ulceration, noninvasive amputation, and long-term disability. This study aimed to develop and validate a nomogram for forecasting the probability of DPN in type 2 diabetes mellitus patients. Methods: From February 2017 to May 2021, 778 patients with type 2 diabetes mellitus were included in this study. We confirmed the diagnosis of DPN according to the Toronto Expert Consensus. Patients were randomly divided into a training cohort (n = 519) and a validation cohort (n = 259). In the training cohort, univariate and multivariate logistic regression analyses were performed, and a simple nomogram was built using the stepwise method. The receiver operating characteristic (ROC), calibration curve, and decision curve analysis were computed in order to validate the discrimination and clinical value of the nomogram model. Results: About 65.7% and 72.2% of patients were diagnosed with DPN in the training and validation cohorts. We developed a novel nomogram to predict the probability of DPN based on the parameters of age, gender, duration of diabetes, body mass index, uric acid, hemoglobin A1c, and free triiodothyronine. The areas under the curves (AUCs) of the nomogram model were 0.763 in the training cohort and 0.755 in the validation cohort. The calibration plots revealed well-fitted accuracy between the predicted and actual probability in the training and validation cohorts. Decision curve analysis confirmed the clinical value of the nomogram. In subgroup analysis, the predictive ability of the nomogram model was strong. Conclusions: The nomogram of age, gender, duration of diabetes, body mass index, uric acid, hemoglobin A1c, and free triiodothyronine may assist clinicians with the early identification of DPN in patients with type 2 diabetes mellitus.

A novel approach to alpha-lipoic acid therapy in the treatment of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is a heterogenic disorder prevalent amongst patients suffering from diabetes mellitus (DM), with symptoms comprising neuropathic pain, paresthesia, and numbness in distal lower limbs. Alpha-lipoic acid (ALA) is proposed as a pathogenesis-oriented treatment option, targeting underlying causes of neural lesions such as hyperglycemia, metabolic and microvascular dysfunctions, and cellular oxidative stress. We performed a comprehensive review of controlled clinical trials demonstrating the clinical usefulness of ALA in the treatment of DPN, published in the last 5 years to determine the benefits of ALA monotherapy and combined treatments with other known antioxidants. We also investigated the differential efficacy of oral versus intravenous ALA administration. Clinical trials show the efficacy of ALA treatment, attributed to its anti-inflammatory, anti-hyperglycemic, and antioxidant properties, as well as its function in the endothelial activation and lipid metabolism parameters. ALA supplementation is associated with amelioration in nerve conduction velocity scores, clinically significant reduction of reported neuropathic pain, burning and paresthesia, as well as a decrease in serum triglycerides, improved insulin sensitivity, and quality of life.

A higher incidence of diabetic peripheral neuropathy may be associated with decreased sleep and increased depression in older adults

Aim: Diabetes mellitus (DM) tends to increase with aging. Nearly half of the patients with DM develop neuropathy (DPN). Despite its high burden and morbidity, the conditions that DPN may be associated with have not been adequately studied in older adults. We aimed to identify sleep duration and comprehensive geriatric assessment components that may be associated with DPN. Material and Method: This is a cross-sectional retrospective study. DPN diagnosed with a medical history, neurologic examination, and electromyography (EMG). 125 diabetic older patients were included. All comprehensive geriatric assessment tests and questions about sleep quality and time were performed. We divided the patients into two groups those without neuropathy and with neuropathy and compared them. Results: The median age of 125 patients was 72 (min-max; 64-94). 58.8% of them were women. The percentage of married people and living with their spouse and slept for 6 hours or more had a lower percentage in the DPN group. Polypharmacy and the percentage of heart failure were significantly higher in the DPN group. Lawton-Brody score, which shows instrumental daily living activities (IADL) and geriatric depression score (GDS) was higher in the DPN group. In logistic regression, we found that depression scores were higher and sleep duration was shorter in the DPN group (respectively, odd ratio:265 p:.012; odd ratio:.1.917 p:.045) Conclusions: DPN in older adults may affect the functionality and be associated with fewer sleep hours and depression. Not only blood glucose regulation but also other factors such as sleep duration and depressed mood may be associated with DPN in older adults.

Dicarbonyl Stress in Diabetic Vascular Disease

Late vascular complications play a prominent role in the diabetes-induced increase in morbidity and mortality. Diabetes mellitus is recognised as a risk factor driving atherosclerosis and cardiovascular mortality; even after the normalisation of blood glucose concentration, the event risk is amplified—an effect called “glycolytic memory”. The hallmark of this glycolytic memory and diabetic pathology are advanced glycation end products (AGEs) and reactive glucose metabolites such as methylglyoxal (MGO), a highly reactive dicarbonyl compound derived mainly from glycolysis. MGO and AGEs have an impact on vascular and organ structure and function, contributing to organ damage. As MGO is not only associated with hyperglycaemia in diabetes but also with other risk factors for diabetic vascular complications such as obesity, dyslipidaemia and hypertension, MGO is identified as a major player in the development of vascular complications in diabetes both on micro- as well as macrovascular level. In diabetes mellitus, the detoxifying system for MGO, the glyoxalase system, is diminished, accounting for the increased MGO concentration and glycotoxic load. This overview will summarise current knowledge on the effect of MGO and AGEs on vascular function.

Scores of peripheral neuropathic pain predicting long-term mortality in patients with type 2 diabetes: A retrospective cohort study

OBJECTIVES

Diabetic peripheral neuropathic pain (DPNP) is a prevalent chronic complication in patients with diabetes. Using a questionnaire is helpful for DPNP screening in outpatients. In this retrospective cohort, we aimed to examine whether DPNP diagnosed based on scoring questionnaires could predict long-term mortality in outpatients with type 2 diabetes.

METHODS

We enrolled 2318 patients who had joined the diabetes pay-for-performance program and completed the annual assessments, including both the identification pain questionnaire (ID pain) and Douleur Neuropathique en 4 questionnaire (DN4), between January 2013 and October 2013. Information on registered deaths was collected up to August 2019.

RESULTS

There was high consistency in the scores between the ID pain and DN4 (r = 0.935, P < 0.001). During the median follow-up of 6.2 years (interquartile range: 5.9-6.4 years), 312 patients deceased. Patients with an ID pain score of ≥ 2 had a higher mortality risk than those with a score of < 2 (hazard ratio [HR] = 1.394, 95%CI: 1.090-1.782), and patients with a DN4 score of ≥ 4 had a higher mortality risk than those with a score of < 4 (HR = 1.668, 95% confidence interval [CI]: 1.211-2.297). Patients consistently diagnosed with DPNP by the ID pain and DN4 had a significantly higher mortality risk (HR = 1.713, 95% CI: 1.223-2.398, P = 0.002), but not those discrepantly diagnosed with DPNP (P = 0.107), as compared with those without DPNP.

CONCLUSIONS

Both the ID pain and DN4 for DPNP screening were predictive of long-term mortality in patients with type 2 diabetes. However, a discrepancy in the diagnosis of DPNP weakened the power of mortality prediction.