Burden of illness associated with painful diabetic peripheral neuropathy among adults seeking treatment in the US: results from a retrospective chart review and cross-sectional survey

Glycemic Targets and Prevention of Complications

CONTEXT

Complications of diabetes mellitus have significant impacts on morbidity, mortality, quality of life, and health costs for individuals. Setting and achieving glycemic targets to prevent these complications is a top priority when managing diabetes. However, patients often already have complications when diagnosed with diabetes mellitus. Therefore, methods to prevent disease progression become a crucial component of diabetes management. The purpose of this article is to review glycemic targets and methods of screening and managing diabetes-related complications.

EVIDENCE ACQUISITION

A PubMed review of the literature pertaining to diabetes mellitus, glycemic targets, microvascular complications, and macrovascular complications was conducted. We reviewed articles published between 1993 and 2024. Guidelines published by nationally recognized organizations in the fields of diabetes, nephrology, and cardiology were referenced. Public health statistics obtained by the Center for Disease Control and Prevention and the National Kidney Foundation were used.

EVIDENCE SYNTHESIS

Achieving glycemic targets and screening for diabetes-related complications at appropriate intervals remains the key factor for early detection and intervention. An algorithmic approach to glycemic management based on individual risk factors is beneficial in choosing pharmacotherapy.

CONCLUSION

The consequences of diabetes-related complications can be detrimental. However, achieving and maintaining glycemic targets combined with diligent screening, reduction of risk factors, and prompt treatment can halt disease progression.

Healthcare costs and medical utilization patterns associated with painful and severe painful diabetic peripheral neuropathy

PURPOSE

Painful diabetic peripheral neuropathy (DPN) is a common complication in patients with diabetes. It is associated with a poor quality of life and high costs of care. This study investigated the impact of painful DPN on healthcare costs and resource utilization.

METHODS

This was a retrospective analysis of administrative claims of adult patients with diabetes (type 1 or 2) from Optum's de-identified Clinformatics® Data Mart Database. Patients were assigned to four cohorts by presence of DPN and pain severity, based on diagnoses and prescription patterns in a one-year baseline. All-cause and diabetes-associated costs were calculated for the year following the index DPN diagnosis. Risk factors associated with presence of severely painful DPN were evaluated.

RESULTS

Relative to those without DPN, patients who had DPN without pain, painful DPN (PDPN), or severe PDPN incurred respective increases of $3,093, $9,349, and $20,887 in average annual all-cause costs. More than half of costs from painful/severe DPN were for prescriptions and inpatient hospitalization. Severe PDPN was associated with elevated odds of diabetic amyotrophy (OR: 8.09; 95% CI: 6.84-9.56), diabetic foot ulcers (OR: 6.54, 95% CI: 6.32-6.76), and loss of mobility (OR: 2.54, 95% CI: 2.48-2.60), among other complications.

CONCLUSIONS

Painful DPN is associated with higher healthcare costs and resource utilization, and a greater risk of debilitating conditions that limit quality of life. Future research should focus on better treatment options and more aggressive pain management strategies to reduce the negative impacts of DPN.

Diabetic Neuropathy: A Guide to Pain Management

PURPOSE OF REVIEW

Diabetic neuropathy is a common complication of diabetes mellitus (DM) and can affect up to 50% of DM patients during their lifetime. Patients typically present with numbness, tingling, pain, and loss of sensation in the extremities. Since there is no treatment targeting the underlying mechanism of neuropathy, strategies focus on preventative care and pain management.

RECENT FINDINGS

Up to 69% of patients with diabetic neuropathy receive pharmacological treatment for neuropathic pain. The United States Food and Drug Administration (FDA) confirmed four drugs for painful diabetic neuropathy (PDN): pregabalin, duloxetine, tapentadol, and the 8% capsaicin patch. Nonpharmacological treatments such as spinal cord stimulation (SCS) and transcutaneous electrical nerve stimulation (TENS) both show promise in reducing pain in DM patients. Despite the high burden associated with PDN, effective management remains challenging. This update covers the background and management of diabetic neuropathy, including its epidemiology, pathogenesis, preventative care, and current therapeutic strategies.

Earlier diagnosis of peripheral neuropathy in primary care: A call to action

Peripheral neuropathy (PN) often remains undiagnosed (~80%). Earlier diagnosis of PN may reduce morbidity and enable earlier risk factor reduction to limit disease progression. Diabetic peripheral neuropathy (DPN) is the most common PN and the 10 g monofilament is endorsed as an inexpensive and easily performed test for DPN. However, it only detects patients with advanced neuropathy at high risk of foot ulceration. There are many validated questionnaires to diagnose PN, but they can be time-consuming and have complex scoring systems. Primary care physicians (PCPs) have busy clinics and lack access to a readily available screening method to diagnose PN. They would prefer a short, simple, and accurate tool to screen for PN. Involving the patient in the screening process would not only reduce the time a physician requires to make a diagnosis but would also empower the patient. Following an expert meeting of diabetologists and neurologists from the Middle East, South East Asia and Latin America, a consensus was formulated to help improve the diagnosis of PN in primary care using a simple tool for patients to screen themselves for PN followed by a consultation with the physician to confirm the diagnosis.

Effects of Physical Cues on Stem Cell-Derived Extracellular Vesicles toward Neuropathy Applications

The peripheral nervous system undergoes sufficient stress when affected by diabetic conditions, chemotherapeutic drugs, and personal injury. Consequently, peripheral neuropathy arises as the most common complication, leading to debilitating symptoms that significantly alter the quality and way of life. The resulting chronic pain requires a treatment approach that does not simply mask the accompanying symptoms but provides the necessary external environment and neurotrophic factors that will effectively facilitate nerve regeneration. Under normal conditions, the peripheral nervous system self-regenerates very slowly. The rate of progression is further hindered by the development of fibrosis and scar tissue formation, which does not allow sufficient neurite outgrowth to the target site. By incorporating scaffolding supplemented with secretome derived from human mesenchymal stem cells, it is hypothesized that neurotrophic factors and cellular signaling can facilitate the optimal microenvironment for nerve reinnervation. However, conventional methods of secretory vesicle production are low yield, thus requiring improved methods to enhance paracrine secretions. This report highlights the state-of-the-art methods of neuropathy treatment as well as methods to optimize the clinical application of stem cells and derived secretory vesicles for nerve regeneration.

Novel drugs affecting diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) poses a significant threat, affecting half of the global diabetic population and leading to severe complications, including pain, impaired mobility, and potential amputation. The delayed manifestation of diabetic neuropathy (DN) makes early diagnosis challenging, contributing to its debilitating impact on individuals with diabetes mellitus (DM). This review examines the multifaceted nature of DPN, focusing on the intricate interplay between oxidative stress, metabolic pathways, and the resulting neuronal damage. It delves into the challenges of diagnosing DN, emphasizing the critical role played by hyperglycemia in triggering these cascading effects. Furthermore, the study explores the limitations of current neuropathic pain drugs, prompting an investigation into a myriad of pharmaceutical agents tested in both human and animal trials over the past decade. The methodology scrutinizes these agents for their potential to provide symptomatic relief for DPN. The investigation reveals promising results from various pharmaceutical agents tested for DPN relief, showcasing their efficacy in ameliorating symptoms. However, a notable gap persists in addressing the underlying problem of DPN. The results underscore the complexity of DPN and the challenges in developing therapies that go beyond symptomatic relief. Despite advancements in treating DPN symptoms, there remains a scarcity of options addressing the underlying problem. This review consolidates the state-of-the-art drugs designed to combat DPN, highlighting their efficacy in alleviating symptoms. Additionally, it emphasizes the need for a deeper understanding of the diverse processes and pathways involved in DPN pathogenesis.

12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Spinal cord stimulation in painful diabetic neuropathy: An overview

Up to 25% of people with diabetes develop painful diabetic neuropathy (PDN). The standard of care pharmacotherapies for PDN have limited efficacy with a considerable side effect profile. Spinal cord stimulation (SCS) is a form of electrical neurostimulation that modulates neural function via electrodes implanted into the spinal epidural space. While low frequency SCS has been shown to be potentially effective for treating pain associated with neuropathies, it masks pain perception by inducing paresthesia. Compared to low frequency SCS, high frequency (10 kHz) SCS delivers paresthesia-free therapy. As was shown in a randomized controlled trial, SENZA-PDN (NCT03228420), 10 kHz SCS is safe and effective for the treatment of painful diabetic neuropathy. 10 kHz SCS offered a comprehensive treatment that improved pain levels, sleep, quality of life, and neurological function. These improvements correlated with a high degree of patient satisfaction. 10 kHz SCS provides a safe, durable and effective treatment for PDN with the unique potential to improve neurological function. In patients for whom durable, effective treatments have been limited thus far, the findings of the SENZA-PDN study are encouraging.

Serum uric acid and risk of diabetic neuropathy: a genetic correlation and mendelian randomization study

Background

Previous observational studies have indicated an association between serum uric acid (SUA) and diabetic neuropathy (DN), but confounding factors and reverse causality have left the causality of this relationship uncertain.

Methods

Univariate Mendelian randomization (MR), multivariate MR and linkage disequilibrium score (LDSC) regression analysis were utilized to assess the causal link between SUA and DN. Summary-level data for SUA were drawn from the CKDGen consortium, comprising 288,648 individuals, while DN data were obtained from the FinnGen consortium, with 2,843 cases and 271,817 controls. Causal effects were estimated primarily using inverse variance weighted (IVW) analysis, supplemented by four validation methods, with additional sensitivity analyses to evaluate pleiotropy, heterogeneity, and result robustness.

Results

The LDSC analysis revealed a significant genetic correlation between SUA and DN (genetic correlation = 0.293, P = 2.60 × 10-5). The primary methodology IVW indicated that each increase of 1 mg/dL in SUA would increase DN risk by 17% (OR = 1.17, 95% CI 1.02-1.34, P = 0.02), while no causal relationship was found in reverse analysis (OR = 1.00, 95% CI 0.98~1.01, P = 0.97). Multivariate MR further identified that the partial effect of SUA on DN may be mediated by physical activity, low density lipoprotein cholesterol (LDL-C), insulin resistance (IR), and alcohol use.

Conclusion

The study establishes a causal link between elevated SUA levels and an increased risk of DN, with no evidence for a reverse association. This underscores the need for a comprehensive strategy in DN management, integrating urate-lowering interventions with modulations of the aforementioned mediators.

Health care resource utilization and costs in patients with painful diabetic neuropathy treated with 10 kHz spinal cord stimulation therapy

BACKGROUND: Diabetic peripheral neuropathy, a common comorbidity of diabetes, is a neurodegenerative disorder that targets sensory, autonomic, and motor nerves frequently associated with painful diabetic neuropathy (PDN). PDN carries an economic burden as the result of reduced work and productivity. A recent multicenter randomized controlled trial, SENZA-PDN (NCT03228420), assessed the impact of high-frequency (10 kHz) spinal cord stimulation (SCS) on pain relief. The effects of high-frequency SCS on health care resource utilization and medical costs are not known. OBJECTIVE: To evaluate the effect of high-frequency (10 kHz) SCS on health care resource utilization (HRU) and medical costs in patients with PDN using data from the SENZA-PDN trial. METHODS: Participants with PDN were randomly assigned 1:1 to receive either 10 kHz SCS plus conventional medical management (CMM) (SCS treatment group) or CMM alone (CMM treatment group). Patient outcomes and HRU up to the 6-month follow-up are reported here. Costs (2020 USD) for each service was estimated based on publicly available Medicare fee schedules, Medicare claims data, and literature. HRU metrics of inpatient and outpatient contacts and costs are reported as means and SDs. Univariate and bivariate analyses were used to compare SCS and CMM treatment groups at 6 months. RESULTS: At 6-month follow up, the SCS arm experienced approximately half the mean rate of hospitalizations per patient compared with the CMM treatment group (0.08 vs 0.15; P = 0.066). The CMM treatment group's total health care costs per patient were approximately 51% higher compared with the SCS treatment group (equivalent to mean annual cost per patient of $9,532 vs $6,300). CONCLUSIONS: Our analysis of the SENZA-PDN trial indicates that the addition of 10 kHz SCS therapy results in lower rates of hospitalization and consequently lower health care costs among patients with PDN compared with those receiving conventional management alone.

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

Background

Distal symmetric polyneuropathy (DSPN) is the most common chronic complication of type 2 diabetes mellitus (T2DM). DSPN may lead to more serious complications, such as diabetic foot ulcer, amputation, and reduced life expectancy. Observational studies have suggested that vitamin D deficiency may be associated with the development of DSPN in T2DM. However, interventional studies have found that low-dose vitamin D supplementation does not significantly improve neuropathy in DSPN. This study aims to evaluate the efficacy and safety of intramuscular injection of high-dose vitamin D (HDVD) in T2DM with DSPN combined with vitamin D insufficiency.

Methods and analysis

We will conduct a multicenter, randomized, double-blinded, and placebo-controlled trial in four large hospitals. All eligible participants will be randomly assigned to either the vitamin D₂ supplement or placebo control group and injected intramuscularly monthly for 3 months. Additionally, anthropometric measurements and clinical data will be collected at baseline and 3 months. Adverse events will be collected at 1, 2, and 3 months. The primary outcome measure is the change in the mean Michigan Neuropathy Screening Instrument (MNSI) score at baseline and 3 months post-intervention. We will use the gold-standard liquid chromatography-tandem mass spectrometry method to distinguish between 25(OH)D₂ and 25(OH)D₃ levels. The MNSN score before the intervention will be used as a covariate to compare the changes between both groups before and after the intervention, and the analysis of covariance will be used to analyze the change in the MNSI score after HDVD supplementation.

Discussion

Glycemic control alone does not prevent the progression of DSPN in T2DM. Some studies have suggested that vitamin D may improve DSPN; however, the exact dose, method, and duration of vitamin D supplementation are unknown. Additionally, neuropathy repair requires HDVD supplementation to sustain adequate vitamin D levels. This once-a-month intramuscular method avoids daily medication; therefore, compliance is high. This study will be the first randomized controlled trial in China to analyze the efficacy and safety of HDVD supplementation for patients with T2DM and DSPN and will provide new ideas for pharmacological research and clinical treatment of diabetic neuropathy.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2200062266.

l-Methylfolate in Diabetic Peripheral Neuropathy: A Narrative Review

OBJECTIVE

One of the most frequently occurring complications of diabetes mellitus is peripheral neuropathy. Despite the painful symptoms associated with diabetic peripheral neuropathy (DPN), the current treatment landscape focuses on managing symptoms without addressing the underlying causes of DPN. This narrative review describes the mechanistic effects and clinical trial data supporting the use of l-methylfolate calcium (LMF), the bioactive form of folate, which is available in the United States as a prescription medical food that also contains other B vitamins for the dietary management of DPN.

METHODS

Preclinical and clinical trial data evaluating the impact of LMF on DPN was identified using PubMed searches for articles published between 2010 and 2023. Search terms included: folate, l-methylfolate, diabetes, neuropathy, and neuropathic pain. Additionally, a literature search was conducted to identify studies related to LMF, genetic polymorphisms, and DPN pathophysiology.

RESULTS

Several studies show that the C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene is linked to greater risk of DPN than other MTHFR variants due to its inhibitory effects on several folic acid metabolic pathways. One double-blind, randomized controlled trial, five open-label studies, and one retrospective study found that LMF has a significant beneficial effect on DPN that extends beyond symptomatic relief to include modulating the underlying pathophysiology that leads to the progression and symptoms of DPN. LMF also significantly improves patient quality of life, with minimal adverse effects.

CONCLUSION

Preclinical and clinical studies have found that LMF can be used to treat the underlying causes of DPN and provide long-lasting symptomatic relief.

Diagnosis, management and impact of painful diabetic peripheral neuropathy: A patient survey in four European countries

AIMS

The aim of this study was to assess patient perspectives and experiences of the impact of neuropathic pain, painful diabetic neuropathy (pDPN) diagnosis and treatment, and the patient-healthcare professional (HCP) relationship.

METHODS

We conducted a quantitative online survey in Germany, the Netherlands, Spain, and the UK among adults with diabetes who responded "yes" to at least four of ten questions of in the Douleur Neuropathique en 4 Questions (DN4) questionnaire.

RESULTS

Of 3626 respondents, 576 met the eligibility criteria. Daily pain was rated as moderate or severe by 79 % of respondents. Most participants reported a negative impact of their pain on sleep (74 %), mood (71 %), exercise (69 %), concentration (64 %) and daily activities (62 %), and 75 % of those in employment had missed work because of their pain in the past year. Overall, 22 % of respondents avoided discussing pain with their HCP, 50 % had not received formal pDPN diagnosis, and 56 % had not used prescribed pain medications. Although two-thirds (67 %) of respondents reported feeling satisfied or very satisfied with treatment, 82 % of these patients still experienced daily moderate or severe pain.

CONCLUSIONS

Neuropathic pain in people with diabetes affects daily life and remains underdiagnosed and undertreated in clinical practice.

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.

Autophagy Dysfunction in a Diabetic Peripheral Neuropathy Model

BACKGROUND

The relationship between autophagy and diabetic peripheral neuropathy (DPN) has been highlighted in few reports. Using an animal model, the authors investigated the relationship between autophagy and DPN, focused particularly on changes in autophagy in Schwann cells.

METHODS

The ultrastructural features of DPN mice were evaluated in vivo using transmission electron microscopy. Dysfunction of autophagy in DPN was evaluated using immunofluorescence microscopy and Western blot analysis of proteins related to autophagy, including Beclin1, LC3, and p62. Reactive oxygen species levels were measured in vitro in glucose-treated Schwann cells. Dysfunction of autophagy in glucose-treated Schwann cells was examined by immunofluorescence microscopy and Western blot analysis.

RESULTS

Reduced myelin thickness and axonal shrinkage were observed in the sciatic nerves of DPN mice. Reactive oxygen species levels were increased in Schwann cells treated with high glucose ( P < 0.05). The expression of Beclin1 was increased in DPN mice and Schwann cells treated with high glucose ( P < 0.05), whereas the expression of LC3-II/LC3-I ratio and p62 were decreased in DPN mice and Schwann cells treated with high glucose ( P < 0.05).

CONCLUSIONS

These results suggest that increased levels of reactive oxygen species induced by high glucose may contribute to autophagy dysfunction in Schwann cells. Autophagy dysfunction especially in Schwann cells may be an underlying cause of DPN.

CLINICAL RELEVANCE STATEMENT

This study presents the pathological mechanism of diabetic peripheral neuropathy.

12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Living with small fiber neuropathy: insights from qualitative focus group interviews

OBJECTIVE

Small fiber neuropathy (SFN) is characterized by chronic neuropathic pain and autonomic dysfunction. Currently, symptomatic pharmacological treatment is often insufficient and frequently causes side effects. SFN patients have a reduced quality of life. However, little is known regarding whether psycho-social variables influence the development and maintenance of SFN-related disability and complaints. Additional knowledge may have consequences for the treatment of SFN. For example, factors such as thinking, feeling, and behavior are known to play roles in other chronic pain conditions. The aim of this study was to obtain further in-depth information about the experience of living with SFN and related chronic pain.

METHODS

Fifteen participants with idiopathic SFN participated in a prospective, semi-structured, qualitative, focus group interview study. The focus groups were audio-recorded, transcribed, and analyzed cyclically after each interview.

RESULTS

The following main themes were identified: "pain appraisal", "coping", "social, work, and health environment", and "change in identity". Catastrophic thoughts and negative emotions were observed. Living with SFN resulted in daily limitations and reduced quality of life.

CONCLUSIONS

Given the results, it can be concluded that an optimal treatment should include biological, psychological, and social components.

Association of sensory phenotype with quality of life, functionality, and emotional well-being in patients suffering from neuropathic pain

ABSTRACT

Neuropathic pain highly affects quality of life, well-being, and function. It has recently been shown based on cluster analysis studies that most patients with neuropathic pain may be categorized into 1 of 3 sensory phenotypes: sensory loss, mechanical hyperalgesia, and thermal hyperalgesia. If these phenotypes reflect underlying pathophysiological mechanisms, they may be more relevant for patient management than underlying neurological diagnosis or pain intensity. The aim of this study was thus to examine the impact of these sensory phenotypes on mental health, functionality, and quality of life. Data of 433 patients from the IMI/EuroPain network database were analyzed, and results of HADS-D/A, Pain Catastrophizing Scale, Euro Quality of Life 5D/-VAS, Brief Pain Inventory, and Graded Chronic Pain Scale between the sensory phenotypes were compared using multiple regression analysis. There was no difference in chronic pain grade, pain intensity, depression, or anxiety scores between phenotypes. Pain interference (Brief Pain Inventory) was higher (P = 0.002); self-reported health state lower (Euro Quality of Life 5D VAS, P = 0.02); and problems regarding mobility (P = 0.008), usual activities (P = 0.004), and self-care (P = 0.039) more prominent (EQ5-D) in the sensory loss compared with the thermal hyperalgesia phenotype. Patients with sensory loss also showed higher pain catastrophizing scores (P = 0.006 and 0.022, respectively) compared with the 2 other groups. Sensory phenotype is associated with the impact of neuropathic pain conditions on well-being, daily functionality, and quality of life but is less associated with pain intensity. These results suggest that the somatosensory phenotype should be considered for personalized pain management.

The Last Decade Publications on Diabetic Peripheral Neuropathic Pain: A Bibliometric Analysis

Background

Diabetic peripheral neuropathic pain (DPNP) is a usual complication of diabetes with a high incidence and mortality. Many diabetes-related studies have been published in various journals. However, bibliometrics and visual analyses in the domain of DPNP research are still lacking. The study aimed to offer a visual method to observe the systematic overview of global research in this field from 2011 to 2021.

Methods

The publications from the Science Citation Index Expanded in Web of Science (WOS) in the past 11 years (from 2011 to 2021) were collected and sorted out, and those related to DPNP were extracted and analyzed. The article language was limited in English. Then, CiteSpace V was used for the bibliometric analysis of the extracted literature.

Results

A total of 1,422 articles met the inclusion criteria. A continuous but unstable growth in the amounts of papers published on DPNP was observed over the last 11 years. The subject sort of the 1,422 papers mainly concentrates on Endocrinology Metabolism, Clinical neurology and Neurosciences from the WOS. According to the research contribution in the field of DPNP, the United States occupies a leading position, with the highest amounts of publications, citations, open access, and the H- index.

Conclusion

This study provides a visual analysis method for the trend of DPNP, and offers some hidden serviceable information that may define new directions for future research.

Systematic Review of Voltage-Gated Calcium Channel α2δ Subunit Ligands for the Treatment of Chronic Neuropathic Pain and Insight into Structure-Activity Relationship (SAR) by Pharmacophore Modeling

BACKGROUND

Neuropathic pain (NP) is a complex symptom related to the nerve damage. The discovery of new drugs for treating chronic NP has been continuing for several decades, while more progress is still needed to be made because of the unsatisfactory efficacy and the side effects of the currently available drugs. Among all the approved drugs for chronic NP, voltage-gated calcium channel (VGCC) α2δ subunit ligands, also known as gabapentinoids, are among the first-line treatment and represent a class of efficacious and relatively safe therapeutic agents. However, new strategies are still needed to be explored due to the unsatisfied response rate.

OBJECTIVES

To review the latest status of the discovery and development of gabapentinoids for the treatment of chronic NP by covering both the marketed and the preclinical/clinical ones. To analyze the structure-activity relationship (SAR) of gabapentinoids to facilitate the future design of structurally novel therapeutic agents targeting VGCC α2δ subunit.

METHODS

We searched PubMed Central, Embase, Cochrane Library, Web of Science, Scopus and Espacenet for the literature and patents of diabetic peripheral neuropathic pain, postherpetic neuralgia, fibromyalgia, voltage-gated calcium channel α2δ subunit and related therapeutic agents from incipient to June 10, 2021. The SAR of gabapentinoids were analyzed by pharmacophore modeling using Phase module in Schrödinger suite.

RESULTS

A variety of gabapentinoids were identified as VGCC α2δ ligands that have ever been under development for the treatment of chronic NP. Among them, four gabapentinoids are marketed, one is at the active late clinical trials, and eight have been discontinued. Pharmacophore models were generated by using Phase module in Schrödinger suite, and common pharmacophores were predicted based on pharmacophoric features and analyzed.

CONCLUSION

The latest progress of the discovery and development of gabapentinoids for the treatment of chronic NP was reviewed. Moreover, the structure-activity relationship (SAR) of gabapentinoids is analyzed by pharmacophore modeling, which will be valuable for the future design of structurally novel therapeutic agents targeting VGCC α2δ subunit.

The Benefits of Add-on Therapy of Vitamin D 5000 IU to the Vitamin D Levels and Symptoms in Diabetic Neuropathy Patients: A Randomized Clinical Trial

Background

Previous studies have demonstrated a significant relationship between vitamin D deficiency and the development of diabetic peripheral neuropathy (DPN). However, current studies are limited regarding the potential therapeutic benefits of vitamin D therapy in these patients.

Objective

This study aimed to assess the effect of oral vitamin D supplementation in patients with diabetic peripheral neuropathy in addition to standard treatment.

Methods

This study was a controlled, open-label, randomized clinical trial with an active comparator randomly allocated with a 1:1 ratio. The experimental group received an add-on oral vitamin D 5000 IU once daily and standard treatment (pregabalin, gabapentin, or amitriptyline) over eight weeks. The control group received standard treatment alone. The measured outcomes were the change in the score of the visual analog scale (VAS), numerical rating scale (NRS), and brief pain inventory (BPI). Vitamin D levels were also measured before and after the trial.

Results

Data from 68 subjects with DPN was collected and analyzed. Most of them (60.3%) were female, aged 64.96 ± 8.3 years. After eight weeks of treatment, the experimental group showed a more significant reduction of mean VAS (-3.34 ± 2.03 vs -2.37 ± 2.2, p=0.044) and burning pain (1.76 ± 7.16 vs 6.18 ± 13.93, p=0.046) scores compared to controls. Mood also improves better in the experimental group (88.2% vs 70.6%, p=0.031). At the end of the study, vitamin D levels were also improved more significantly in the experimental group (40.02 ± 15.33 ng/mL vs 18.73 ± 6.88 ng/mL; p<0.001) with greater changes from the baseline to week 8 (+24.14±13.68 ng/mL vs +3.10±4.20 ng/mL; p<0.001) compared to control group. The intervention group showed a negative correlation between vitamin D level and VAS score (r = -0.403, P = 0.018). There were no adverse events recorded in this study.

Conclusion

The addition of oral vitamin D 5000 IU to standard treatment significantly improves pain, mood, and vitamin D levels more effectively than standard treatment alone in patients with diabetic neuropathy.

Trial Registration

ClinicalTrials.gov.no NCT04689958.

12. Retinopathy, Neuropathy, and Foot Care: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Painful Diabetic Peripheral Neuropathy Study of Chinese Outpatients (PDNSCOPE): A Multicentre Cross-Sectional Registry Study of Clinical Characteristics and Treatment in Mainland China

INTRODUCTION

This aim of this study was to delineate current clinical scenarios of painful diabetic peripheral neuropathy (PDN) and associated anxiety and depression among patients in Mainland China, and to report current therapy and clinical practices.

METHODS

A total of 1547 participants were enrolled in the study between 14 June 2018 and 11 November 2019. Recruitment was conducted using a multilevel sampling method. Participants' demographics, medical histories, glucose parameters, Douleur Neuropathique 4 Questionnaire (DN4) scores, visual analogue scale (VAS) pain scores, Patient Health Questionnaire 9 (PHQ-9) scores, Generalised Anxiety Disorder 7 (GAD-7) scores and therapies were recorded.

RESULTS

The male-to-female ratio was 1.09:1 (807:740), and the mean age at onset was 61.28 ± 11.23 years. The mean DN4 score (± standard deviation) was 4.91 ± 1.88. The frequencies of DN4 sub-item phenotypes were: numbness, 81%; tingling, 68.71%; pins and needles, 62.90%; burning, 53.59%; hypoaesthesia to touch, 50.16%; electronic shocks, 43.31%; hypoaesthesia to pinprick, 37.94%; brushing, 37.82%; painful cold, 29.61%; and itching, 25.86%. Age, diabetic duration, depression history, PHQ-9 score and GAD-7 score were identified as risk factors for VAS pain score. Peripheral artery disease (PAD) was a protective factor for VAS pain score. For all participants currently diagnosed with PDN and for those previously diagnosed PDN, fasting blood glucose (FBG) was a risk factor for VAS; there was no association between FBG and VAS pain score for PDN diagnosed within 3 months prior to recruitment. Utilisation rate of opium therapies among enrolled participants was 0.71% , contradiction of first-line guideline recommendation for pain relief accounted for 9.43% (33/350) and contradiction of second-line guideline recommendation for opium dosage form was 0.57% (2/350).

CONCLUSION

Moderate to severe neuropathic pain in PDN was identified in 73.11% of participants. Age, diabetic duration, depression history, PHQ-9 score, GAD-7 score and FBG were risk factors for VAS pain scores. PAD was protective factor. The majority of pain relief therapies prescribed were in accordance with guidelines.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03520608, retrospectively registered, 2018-05-11.

Diabetes severity measured by treatment control status and number of anti-diabetic drugs affects presenteeism among workers with type 2 diabetes

BACKGROUND

The number of people with diabetes is increasing and resulting in major economic losses. Presenteeism accounts for the majority of economic losses, so measures against presenteeism are important. This study investigated the relationship between severity of type 2 diabetes and presenteeism.

METHODS

A cross-sectional study was conducted among workers over 40 years of age. Participants were classified as normal group or diabetic treatment group using their medical examination results and health insurance claims data. Diabetic treatment groups were described by degree of treatment control: Good (HbA1c < 7%), Intermediate (7% ≤ HbA1c < 8%), and Poor (8% ≤ HbA1c). Therapy type was also divided into monotherapy and combination therapy. Logistic regression analysis was performed to predict presenteeism loss using the Quantity and Quality method.

RESULTS

Data on 13,271 workers were analyzed. Presenteeism loss was significantly higher in all treatment control groups compared with the normal group, particularly for the intermediate and poor control groups. The monotherapy group did not differ from the normal group, but presenteeism loss was significantly higher in the combination therapy group than the normal group.

CONCLUSIONS

Presenteeism loss in workers with diabetes may be affected by diabetes severity, and even if treatment control were good, presenteeism loss could occur when the number of anti-diabetic drugs was high. Therefore, it is important to provide early intervention and continuous support as a preventive measure against not only diabetes and diabetes-related complications but also presenteeism.

Long-term complications of type 1 diabetes: what do we know and what do we need to understand?

Long-term complications of type 1 diabetes (T1D) include microvascular complications and macrovascular disease. Despite the important advances in the treatment of T1D of the last decades, these complications still represent the leading cause of morbidity and mortality in patients with T1D. Extensive evidence indicates that structural and functional alterations of the kidney, retina, nerves and large arteries occur already in the first years after the onset of diabetes. We performed a comprehensive review of the available evidence on screening, diagnosis, prevention and treatment of vascular complications of T1D. In particular, we focused on three major challenges related to long-term complications of T1D: 1) finding of new biomarkers and diagnostic methods able to identify early signs of complications; 2) identifying specific risk factors for the development of these complications; 3) identifying and implementing new therapeutic strategies able to prevent the development and progression of vascular complications.

The Impact of Diabetes Status on Presenteeism in Japan

OBJECTIVE

This study aimed to investigate the impact of diabetes status on presenteeism in companies in Japan.

METHODS

A cross-sectional study was conducted among workers aged 40 years or older. Using medical examination results and health insurance claims data, participants were classified as normal, borderline, or diabetic. The diabetic group was further classified as untreated or treated. The Quantity and Quality (QQ) method was used as an evaluation index of presenteeism. Logistic regression analysis was performed to predict presenteeism loss.

RESULTS

Data on 13,292 people were analyzed. Presenteeism loss was significantly higher in the diabetic group versus the normal group. The untreated group did not differ from the normal group, but presenteeism loss was significantly higher in the treated group.

CONCLUSIONS

Presenteeism loss may occur among diabetic workers in Japan and can be caused by diabetes treatment.

Efficacy and safety of mirogabalin treatment in patients with diabetic peripheral neuropathic pain: A systematic review and meta-analysis of randomised controlled trials

AIM

We aimed to perform a systematic review and meta-analysis to examine the efficacy and safety of mirogabalin in patients with diabetic peripheral neuropathic pain (DPNP).

METHODS

We searched four databases from inception to 1st July 2020. We included all randomised controlled trials (RCTs) which assessed the effectiveness and safety of mirogabalin in patients with DPNP. We evaluated the quality of the included RCTs using the Cochrane risk of bias assessment tool. We pooled dichotomous outcomes as risk ratios and continuous outcomes as mean differences with 95% confidence intervals, both under the random- or fixed-effects model.

RESULTS

Three RCTs matched our inclusion criteria with a total of 1732 patients with DPNP: 1057, 534 and 141 patients received mirogabalin, placebo and pregabalin, respectively. The quality of included RCTs was marked as moderate-to-high. Mirogabalin treatment was significantly associated with a significant reduction in the average daily pain score (ADPS) compared with placebo over 7 weeks. Compared with pregabalin, mirogabalin was significantly associated with more decrease in ADPS only after 3, 4 and 5 weeks. The proportion of patients with ≥30% and ≥50% reduction in the ADPS was significantly higher in the mirogabalin vs placebo and pregabalin groups. Compared with placebo, mirogabalin was significantly associated with more adverse events of dizziness, increased weight, peripheral oedema and somnolence. The safety profile was comparable between mirogabalin and pregabalin.

CONCLUSIONS

Our systematic review and meta-analysis revealed that in patients with DPNP, mirogabalin treatment was superior to placebo and pregabalin in decreasing the ADPS over time. Besides, mirogabalin was largely safe and associated with some adverse events that could be managed conservatively.

Diabetes is associated with greater leg pain and worse patient-reported outcomes at 1 year after lumbar spine surgery

Although patients with diabetes reportedly have more back pain and worse patient-reported outcomes than those without diabetes after lumbar spine surgery, the impact of diabetes on postoperative recovery in pain or numbness in other regions is not well characterized. In this study, the authors aimed to elucidate the impact of diabetes on postoperative recovery in pain/numbness in four areas (back, buttock, leg, and sole) after lumbar spine surgery. The authors retrospectively reviewed 993 patients (152 with diabetes and 841 without) who underwent decompression and/or fixation within three levels of the lumbar spine at eight hospitals during April 2017–June 2018. Preoperative Numerical Rating Scale (NRS) scores in all four areas, Oswestry Disability Index (ODI), and Euro quality of life 5-dimension (EQ-5D) were comparable between the groups. The diabetic group showed worse ODI/EQ-5D and greater NRS scores for leg pain 1 year after surgery than the non-diabetic group. Although other postoperative NRS scores tended to be higher in the diabetic group, the between-group differences were not significant. Diabetic neuropathy caused by microvascular changes may induce irreversible nerve damage especially in leg area. Providers can use this information when counseling patients with diabetes about the expected outcomes of spine surgery.

Predicting the quality of life based on pain dimensions and psychiatric symptoms in patients with Painful diabetic neuropathy: a cross-sectional prevalence study in Iranian patients

Background

This study aimed to predict the quality of life (QOL) in patients with Painful Diabetic Neuropathy (PDN) based on pain severity, pain catastrophizing, pain acceptance, depression, anxiety, and sleep disturbance. Also, this study was aimed to assess the prevalence of psychiatric symptoms in Iranian patients with PDN.

Method

1120 patients (mean age, 53.6 ± 12.6 years) participated in the research. Data were collected by the Quality of life questionnaire (NeuroQoL); Beck Depression Inventory, Beck Anxiety Inventory, the visual analog scale for pain severity, Pain Catastrophizing Scale (PCS), Chronic Pain Acceptance Questionnaire (CPAQ) and Pittsburgh Sleep Quality Index (PSQI). Finally, the data were analyzed using SPSS-26 by multiple regression analysis.

Results

The results showed the regression models’ significance, and the dependent variables predicted 42% of total changes in the QOL. The most significant predicting factors were depression, pain catastrophizing, pain acceptance, pain severity, sleep disturbance, and anxiety in order. In patients with PDN, the prevalence of sleep disturbances, depression, and anxiety were 85.5%, 68.2%, and 62.1%, respectively. Also, comorbid depression and anxiety were found in 47% of patients.

Conclusion

Results demonstrated a significant relationship between pain-related and psychiatric dimensions with QOL. Thus, it is suggested to design more specific psychological-based rehabilitation interventions in which these variables are considered. They should focus on more significant variables (such as depression and pain catastrophizing) to reach better treatment outcomes. Furthermore, this research shows a high level of anxiety, depression, and sleep disturbance in Iranian patients with PDN. Thus, experts and clinicians are suggested to focus on reducing these psychiatric symptoms.

Prevalence of peripheral neuropathy and associated pain in patients with diabetes mellitus: Evidence from a cross-sectional study

Background

Diabetic peripheral neuropathy (DPN) is the most common and troublesome complication of diabetes mellitus. It affects almost half the population with diabetes and worsens quality of life of the patient. This study was aimed to determine the prevalence of peripheral neuropathy and associated pain in patients with diabetes mellitus.

Methods

This was a cross-sectional study conducted over a period of six months. Patient's ≥ 18 years with confirmed diagnosis of diabetes mellitus were included in the study. Patients with hypothyroidism, medical illness such as cancer, liver or renal disease, cervical or lumbar spondylosis, pregnant patients with diabetes and patients receiving any treatment that might influence nerve function (e.g., cytotoxic or antiepileptic agents) were excluded from the study. DPN was diagnosed using 10 g monofilament test. The S-LANSS questionnaire was used to assess the associated painful symptoms. Association was calculated using chi-square test. A p- value of ≤0.05 was considered statistically significant. All the statistical analysis was performed using SPSS v22.

Result

The overall prevalence of DPN was found to be 28.85% from which 88% patients were found to have painful symptoms. A significant association of DPN was observed with the duration of diabetes (p = 0.004), poor glycaemic control (p = 0.03) and other diabetic complications such as nephropathy (p = 0.002). No association of neuropathy was found with retinopathy and hypertension. Duration of diabetes (>15 years), and HbA1c (>9%) was found to be positively associated the painful DPN.

Conclusion

The current study found a high prevalence of DPN and it was found to be significantly associated with duration of diabetes, poor glycaemic control and nephropathy.

Trends in Pain Medication Initiation Among Patients With Newly Diagnosed Diabetic Peripheral Neuropathy, 2014-2018

This cohort study assesses trends in the rates of initiation of pain medication among patients with newly diagnosed diabetic peripheral neuropathy and the types of pain medication prescribed from 2014 to 2018.

11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2021

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc21-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc21-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Vitamin D deficiency is associated with painful diabetic neuropathy

BACKGROUND

The aetiology of painful diabetic neuropathy is unclear. We have evaluated vitamin D levels in diabetic patients with and without painful neuropathy.

METHODS

Forty-three patients with type 1 diabetes and painless (DPN) (n = 20) or painful (PDN) (n = 23) neuropathy and 14 non-diabetic healthy control subjects (C) underwent assessment of neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy, corneal confocal microscopy (CCM) and measurement of serum 25(OH)D.

RESULTS

There were no significant differences for age, BMI, HbA_1c , lipids, neurological deficits, QST, electrophysiology, intra-epidermal nerve fibre density (IENFD) and corneal nerve morphology between patients with DPN and PDN. Both positive (hyperalgesia and allodynia) and negative symptoms (paraesthesia and numbness) of diabetic neuropathy were greater in PDN compared with DPN (P = .009 and P = .02, respectively). Serum 25(OH)D levels were significantly lower in PDN (24.0 ± 14.1 ng/mL) compared with DPN (34.6 ± 15.0 ng/mL, P = .01) and controls (34.1 ± 8.6 ng/mL, P = .03). The odds ratio in favour of painful diabetic neuropathy was 9.8 [P = .003 (95% CI, 2.2-76.4)] for vitamin D deficiency (<20 ng/mL) and 4.4 [P = .03 (95% CI, 1.1-19.8)] for vitamin D insufficiency (<30 ng/mL).

CONCLUSIONS

This study suggests that vitamin D deficiency and insufficiency are associated with painful diabetic neuropathy.

Status of Analgesic Drugs and Quality of Life Results for Diabetic Peripheral Neuropathy in China

OBJECTIVE

The purpose of this study is to describe the current clinical situation of patients with painful diabetic peripheral neuropathy (DPN) and related anxiety, depression, and the quality of life of patients in mainland China, and to report the current status of the use of analgesics.

METHODS

Between June 15, 2021, and October 15, 2021, a total of 401 participants participated in the study. Recruitment was carried out using a multi-level sampling method. Participants' demographics, medical history, analgesic use, Michigan Symptom Score (MNSI), Numerical Rating Scale (NRS) pain score, Patient Health Questionnaire 9 (PHQ-9) score, Generalized Anxiety Disorder 7 (GAD) -7) Score, quality of life score (SF-12) and diabetes treatment status were collected.

RESULTS

Among the participants, there were 236 male patients and female patients. Participants were 322 patients over 40 years old. Regarding the use of analgesics: 132 patients reported using analgesics, 221 patients reported not using analgesics, and 48 patients reported having used analgesics. The results of the scale showed that the scores of NRS, GAD-7, PHQ-9 and SF-12 were 5.12 ± 2.15, 6.33 ± 3.67, 8.46 ± 4.07 and 47.84 ± 19.92 for patients who used analgesics, Compared with patients who did not use analgesics (NRS: 1.99 ± 1.7, GAD-7: 1.81 ± 2.81, PHQ-9: 3.13 ± 4.10, SF-12: 78.34 ± 21.66) there are significant differences (p< 0.001). In addition, patients' NRS scores are also closely related to GAD-7, PHQ-9 and SF-12 scores.

CONCLUSION

The severity of symptoms, mental status and quality of life of patients who used analgesics were more severe than those of patients who did not use analgesics. Pregabalin is still the preferred analgesic for patients with painful DPN, and the use of opioids in my country is extremely low, which is consistent with current international guidelines. Age, diabetic duration, DPN duration, PHQ-9 score, GAD-7 score and SF-12 scores are closely related to NRS pain scores. In addition, there are still a considerable number of patients who have not used analgesics due to financial burdens and other reasons, suggesting that China still has insufficient pain management in DPN patients.

A Review on Mechanistic and Pharmacological Findings of Diabetic Peripheral Neuropathy including Pharmacotherapy

BACKGROUND

Chronic hyperglycemia and related complications involving peripheral nerves in diabetes are one of the most severe microvascular complications with an average prevalence of 50-60%. Diabetic neuropathy is among the vascular disorders of diabetes, the most debilitating and crippled, lethal condition impacting patients's quality of life.

METHODS

In the present review article, several hypotheses associated with the pathogenesis of Diabetic Peripheral Neuropathy (DPN) have been introduced, among them metabolic pathways associated with polyol pathway, oxidative stress, production of reactive oxygen species (ROS) amplified under chronic hyperglycemic conditions and activation of transcription factor Nuclear factor-κB (NF- κB). The review article also possesses pathogenetic and pharmacologic treatments along with others, including acupressure, lidocaine, and capsaicin for DPN.

CONCLUSION

It may be concluded that we can combat the pathogenesis of DPN with different suggested treatments.

Neuropathic damage in the diabetic eye: clinical implications

In recent years, emerging evidence support that the eye is target of diabetes neuropathy. There are two components of the eye that are mainly involved in the neurodegenerative process induced by diabetes: the retina and the cornea. The study of functional and structural changes in these components of the eye will provide useful information to identify subjects with diabetes at risk of diabetic peripheral neuropathy and dementia. In this review the state of the art regarding the evidence and clinical implications of this emerging concept will be provided. In addition, the relationship between retinal and corneal neurodegeneration with peripheral neuropathy and cognitive decline will be analyzed. Finally, the scientific gaps than need to be covered and will be critically examined.

Psychosocial Factors in Painful Diabetic Neuropathy: A Systematic Review of Treatment Trials and Survey Studies

OBJECTIVE

Diabetes mellitus is associated with a number of complications that can adversely impact patients' quality of life. A common and often painful complication is painful diabetic neuropathy. The aims of this study were to systematically review and summarize evidence from studies of psychological treatments and psychosocial factors related to painful diabetic neuropathy and assess the methodological quality of these studies.

METHODS

Electronic databases, related reviews, and associated reference lists were searched. Summaries of participants' data relating to the efficacy of psychological treatments and/or to associations between psychosocial factors and outcomes in painful diabetic neuropathy were extracted from the included studies. The methodological quality of included studies was assessed using two standardized quality assessment tools.

RESULTS

From 2,921 potentially relevant titles identified, 27 studies were included in this systematic review. The evidence suggests that depression, anxiety, sleep, and quality of life are the most studied variables in relation to pain outcomes in painful diabetic neuropathy and are consistently associated with pain intensity. The magnitude of the associations ranged from small to large.

CONCLUSIONS

Research into psychosocial factors in painful diabetic neuropathy is unexpectedly limited. The available evidence is inconsistent and leaves a number of questions unanswered, particularly with respect to causal associations between variables. The evidence reviewed indicates that depression, anxiety, low quality of life, and poor sleep are associated with pain in painful diabetic neuropathy. The disproportionate lack of research into psychological treatments for painful diabetic neuropathy represents a significant opportunity for future research.

The efficacy of vitamin D supplementation on painful diabetic neuropathy: Protocol for a systematic review and meta-analysis

BACKGROUND

Painful diabetic neuropathy (PDN) is one of the main and severe complications of diabetic patients, which not only accelerates the occurrence of ulcers of diabetic foot and amputation of lower extremities but also severely affects the quality of life. It is common that vitamin D deficiency in diabetic patients and especially in these patients diagnosed with diabetic peripheral neuropathy. Previous studies have proved that there is an apparent vitamin D deficiency in PDN patients, and vitamin D supplementation can effectively improve patients' pain symptoms and neurologic function. However, the evidence of these studies is unconvincing. Therefore, our research objective is to explore the effectiveness and security of vitamin D supplements on PDN.

METHODS

We will include randomized controlled trials on vitamin D supplementation in the treatment of PDN. And we will retrieve 8 electronic databases concerning this theme. The English databases mainly retrieve PubMed, Web of Science, Embase, and the Cochrane Library, while CNKI, VIP, CBM, and Wanfang database will be used to retrieve the Chinese Literature. There is no definite time limit for retrieval literatures, and the languages will be limited to Chinese and English. Besides, some clinical registration tests and gray literatures are also researched by us. The primary outcomes of our study are the amelioration of pain symptoms and assessment of peripheral nerve function. And some changes of biochemical indicators including fasting blood glucose, 2 hours postprandial blood glucose, glycosylated hemoglobin, calcium, and serum vitamin D level from preintervention and postintervention, adverse events will be regarded as secondary outcomes. The Review Manager RevMan5.3 will be used for meta-analysis of studies are included.

RESULTS

In this systematic review and meta-analysis, higher quality data evidence on vitamin D supplementation for PDN will be provided.

CONCLUSION

Our study will eventually provide a proof of the efficacy and safety of vitamin D supplementation in patients with PDN, and to add a new option for the prevention and treatment of PDN patients.

INPLASY REGISTRATION NUMBER

INPLASY202050065.

Diabetic Polyneuropathy - Advances in Diagnosis and Intervention Strategies

Over half of people with diabetes mellitus develop diabetic polyneuropathy (DPN), which is a major cause of reduced quality of life due to disabling neuropathic pain, sensory loss, gait instability, fall-related injury, and foot ulceration and amputation. The latter represents a major health and economic burden, with lower limb amputation rates related to diabetes increasing in the UK. There is a need for early diagnosis of DPN so that early management strategies may be instigated, such as achieving tight glucose control and management of cardiovascular risk factors, in an attempt to slow its progression. To this end, a one-stop microvascular assessment involving a combined eye, foot and renal screening clinic has proven feasible in the UK. Unfortunately, there are currently no approved disease-modifying therapies for DPN. Some disease-modifying agents have demonstrated efficacy, but further large trials using appropriate clinical endpoints are required before these treatments can be routinely recommended. There has been emerging evidence highlighting a reduction in vitamin D levels in cases of painful DPN and the potential for vitamin D supplementation in deficient individuals to improve neuropathic pain; however, this needs to be proved in randomised clinical trials. The use of established agents for neuropathic pain in DPN is limited by poor efficacy and adverse effects, but patient stratification using methods such as pain phenotyping are being tested to determine whether this improves the outcomes of such agents in clinical studies. In addition, innovative approaches such as the topical 8% capsaicin patch, new methods of electrical stimulation and novel therapeutic targets such as NaV1.7 offer promise for the future. This article aims to discuss the challenges of diagnosing and managing DPN and to review current and emerging lifestyle interventions and therapeutic options.

A systematic review on the efficacy of vitamin D supplementation on diabetic peripheral neuropathy

BACKGROUND & AIMS

Vitamin D deficiency is known to be prevalent in patients with diabetes and in particular in those having symptoms of diabetic peripheral neuropathy (DN). Thus, it is worthy to investigate whether a supplementation of vitamin D would improve pain among those having diabetes and DN.

METHODS

A systematic literature search was performed to identify studies that reported the impact of vitamin D supplementation on the signs and symptoms of DN. Random effect models were used to meta-analyze effect sizes. Quality assessment was also performed.

RESULTS

Four studies including 364 patients met the inclusion criteria. Meta-analytical results were as follows: Serum Vitamin D level change of 1.39 (95% CI = 1.220 to 1.573, p = 0.008), HbA1c change of 0.134 (95% CI = -0.153 to 0.418, p = 0.3), McGill Pain Questionnaire score of 1.14 (95% CI = 1.222 to 1.672, p < 0.0001), all in favor of the vitamin D supplementation group. Non-meta-analytical results of all individual studies showed significant amelioration of pain scores. One study reported no significant change in nerve conduction study. Pain improvement was not correlated to baseline or change in serum vitamin D level.

CONCLUSION

Vitamin D supplementation could be an added value in the treatment of painful peripheral diabetic neuropathy. Amelioration in pain might be related to the absolute value of vitamin D attained following supplementation. The findings of this review are promising and further research with large sample randomized trials is warranted.

Is it possible to substitute the monofilament test for the Ipswich Touch Test in screening for peripheral diabetic neuropathy?

BACKGROUND

This study aimed to assess the agreement and efficacy of the Ipswich Touch Test compared to the monofilament test in individuals with type 2 diabetes.

MATERIALS AND METHODS

A cross-sectional and analytical study was conducted. The inclusion criteria were patients with type II diabetes (n = 250) who did not present ulcers or amputation in either foot. The exclusion criteria were as follows: patients who presented sequelae of cerebrovascular disease or other neurological pathologies, as well as diagnoses of malignancy, alcohol abuse, liver cirrhosis, hepatitis B, AIDS, hypothyroidism, chronic kidney disease or lupus erythaematosus, as these clinical conditions could influence or bias the results (Won and Park in Endocrinol Metab 31:230-238, 2016). Sensitivity, specificity, predictive values, likelihood ratios, and Kappa index were calculated. Other factors assessed were glycated haemoglobin and body mass index.

RESULTS

Most of the participants were female (71.2%), and glycated haemoglobin (HbA1c) was greater than 7% in 54.4% of the patients. The mean age was 59.43 years, and the mean time since diagnosis was 12.38 years. The Kappa index was 0.819 (p < 0.001), and the Ipswich Touch Test had a sensitivity of 83.33%, a specificity of 97.66%, a positive predictive value of 85.71%, a negative predictive value of 97.21%, a positive likelihood ratio of 30.19%, and a negative likelihood ratio of 0.17%. The level of significance was 5% in this study.

CONCLUSION

The Ipswich Touch Test resented good agreement and efficacy compared to the gold standard-the 10 g monofilament test.

11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc20-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Mirogabalin for the treatment of diabetic peripheral neuropathic pain: A randomized, double-blind, placebo-controlled phase III study in Asian patients

AIMS/INTRODUCTION

This study evaluated the efficacy and safety of mirogabalin, a novel, potent, selective ligand of the α2 δ subunit of voltage-dependent Ca2+ channels, for the treatment of diabetic peripheral neuropathic pain (DPNP).

MATERIALS AND METHODS

During this double-blind, multisite, placebo-controlled phase III study, Asian patients aged ≥20 years with type 1 or 2 diabetes and DPNP were randomized 2:1:1:1 to a placebo, mirogabalin 15, 20 or 30 mg/day for up to 14 weeks, with a 1- to 2-week titration (NCT02318706). The primary endpoint was the change from baseline in average daily pain score (ADPS) at week 14, defined as a weekly average of daily pain (0 = no pain to 10 = worst possible pain, for the past 24 h).

RESULTS

Of 834 randomized patients, 330, 164, 165 and 165 received placebo, mirogabalin 15, 20 or 30 mg/day, respectively, and were included in analyses (modified intention-to-treat population, n = 824); 755 (90.5%) completed the study. At week 14, the least squares mean average daily pain score change from baseline was -1.31, -1.34, -1.47 and -1.81, respectively, showing statistical significance for mirogabalin 30 mg/day versus placebo (P = 0.0027). The treatment-emergent adverse events observed were mostly mild-to-moderate in all mirogabalin doses, and the most frequent treatment-emergent adverse events were nasopharyngitis, somnolence, dizziness, peripheral edema and weight increase.

CONCLUSIONS

Mirogabalin relieved DPNP in a dose-dependent manner; mirogabalin 30 mg/day showed statistically significant pain relief (vs placebo) in Asian DPNP patients. All doses of mirogabalin tested were well tolerated.

Anxiety, depression and sleep disorders in patients with diabetic neuropathic pain: a systematic review

Introduction: Diabetic neuropathic pain (DNP) is a disabling complication suffered by patients with diabetic neuropathy. DNP coexists with different conditions, especially mental and sleep disorders, which seem to impair the management and course of the disease. However, there is a lack of accurate results about their prevalence. Consequently, the authors analyze the prevalence of anxiety, depression and/or sleep disorders in DND patients.Areas covered: Among the 206 articles found in the search, 8 studies with data from 5 different countries fulfilled the inclusion criteria. The prevalence of anxiety reported ranged between 7.8%-60.4% and that of depression between 13.6%- 50.6%. The two conditions coexist in 26.4%-30.6% in DND patients. A higher prevalence was found when the information was obtained using scales than when it came from medical records. The prevalence of sleep disorders found ranged from 41.6%-43.8%. However, there is lack of information about and the results are often expressed using the mean scores of the scales.Expert opinion: Although the data in the literature vary, a high prevalence of anxiety, depression and sleep comorbidities exists among patients with DNP. These results reaffirm the need to perform systematic evaluations and to identity their presence using validated instruments to obtain more reliable results.

The effects of botulinum toxin type A injection on pain symptoms, quality of life, and sleep quality of patients with diabetic neuropathy: A randomized double-blind clinical trial

Background: Neuropathic pain is one of the most common problems in patients with diabetes mellitus (DM). In this study, the effect of botulinum toxin type A (BTX-A) on neuropathic pain, quality of sleep, and quality of life of diabetic patients with sensorimotor polyneuropathy was studied. Methods: This randomized placebo-controlled trial study was carried out in a double-blind (patient-researcher) method. The study was performed on 32 patients with type 2 DM. Neuropathy was confirmed by Douleur Neuropathique 4 (DN4) Questionnaire and nerve conduction study (NCS). The patients were randomly assigned to two intervention and control groups based on the random numbers table. After selecting the subjects, we used 36-Item Short Form Health Survey (SF-36), Neuropathic Pain Scale (NPS), Visual Analogue Scale (VAS), and Pittsburgh Sleep Quality Index (PSQI) questionnaires before and after 3 months of 100 units BTX-A injection (as intervention group) or same amount of chloride sodium (as control group) to the subjects' feet. The data were analyzed by SPSS software using independent two-sample t-test, chi-square test, and one-way repeated measures analysis of variance (ANOVA). Results: 12 male and 20 female patients participated in this study. There was a significant difference in the mean VAS, PSQI, physical dimension of the SF-36, and some NPS indices over time (12 weeks) (P < 0.001). Conclusion: The results of this study showed that BTX-A reduced neuropathic pain and improved the quality of life and sleep in people with diabetic neuropathy.