Diabetic polyneuropathy and pain, prevalence, and patient characteristics: a cross-sectional questionnaire study of 5,514 patients with recently diagnosed type 2 diabetes

Panic attack symptoms in patients with diabetic peripheral neuropathy

Assessment of diabetic peripheral neuropathy (DPN) usually focuses on nerve damage resulting from hyperglycaemia. However, screening for common psychiatric disorders may improve the recognition of psychopathology in patients with DPN. This epidemiological cohort study aimed to evaluate the prevalence of panic attack symptoms in patients with DPN compared toa control group of healthy individuals without type 2 diabetes mellitusorDPN.Additionally, this study sought to compare the severity of these symptoms between the two groups.The study was conducted via a survey over three years in an accredited practice of physicians at the Medical University-Sofia. A total of267 participants were included, comprising 83 patients with DPN and 184healthy controls. Both groups completed the Prime-MD Patient Health Questionnaire. The results indicated significant differences between the two study groups(t[127.513] = 3.293; p < 0.01), and patients with DPN had a higher prevalence of panic attack symptoms than those in the control group.Furthermore, significant differences were observed in the severity of panic attack symptoms within the DPN group (t[(81] = 2.017, p < 0.05).Patients who had experienced DPN for more than one year reported more severe symptoms than those who had experienced it for less than oneyear. Our results indicate that the high prevalence of panic attack symptoms inpatients with DPN highlights the need for integrated screening for psychiatric disorders within the overall management plan for diabetes mellitus.

Understanding the Impact of Diabetic Peripheral Neuropathy and Neuropathic Pain on Quality of Life and Mental Health in 6,960 People With Diabetes

OBJECTIVE

Diabetic peripheral neuropathy (DPN) and neuropathic pain impacts quality of life (QoL) and mental health negatively. This cross-sectional survey study aimed to 1) elucidate the associations between painful and painless DPN and QoL, mental health, and socioeconomic factors, 2) assess the prevalence of sensory pain descriptors, and 3) evaluate the association between descriptors and the above factors.

RESEARCH DESIGN AND METHODS

Participants were grouped into people with (n = 1,601) and without (n = 5,359) DPN based on the Michigan Neuropathy Screening Instrument questionnaire. Participants with DPN were subsequently divided into people with (n = 1,085) and without (n = 516) concomitant neuropathic pain based on the modified Douleur Neuropathique en 4 Questions-interview.

RESULTS

The study showed diminished QoL (36-item Short Form Health Survey [SF-36]: 55.1 [interquartile range 36.7, 73.6], 82.2 [63.6, 90.9]) and poorer mental health (Hospital Anxiety and Depression Scale, subscale for anxiety [HADS-A]: 5.00 [2, 9], 2.00 [1, 5]; HADS-subscale for depression [HADS-D]: 4.00 [1, 8], 1.00 [0, 3]) in participants with DPN compared with participants without DPN. The addition of pain diminished QoL (SF-36: 50.7 [34.8, 69.8]) and mental health (HADS-A: 6 [3, 10], HADS-D: 4 [1, 8]) further. The most prevalent pain descriptor in participants with painful DPN were burning pain (73%), while the most prevalent sensory descriptor was pins-and-needles (93%). An interesting finding is the high prevalence of itch (44%). Weak associations with mental health and QoL were present for cold pain, electric pain, and itch.

CONCLUSIONS

An increased focus on differences in QoL, mental health, and pain phenotypes is of importance to move the field forward toward more interdisciplinary, personalized treatment.

The impact of pancreas transplantation on diabetic complications: A systematic review

BACKGROUND

Pancreas Transplantation (PT) provides optimal treatment for patients with severe complicated Type 1 Diabetes Mellitus (T1DM). Restoration of beta-cell mass allows return to euglycaemia and insulin independence. We aimed to examine its impact on the secondary complications associated with severe T1DM including diabetic eye disease, neuropathy and cardiovascular disease.

METHODS

A database search using MedLINE to identify publications to April 2023 was conducted. Searches were performed using MeSH terms 'Pancreas Transplantation' AND 'Diabetes Mellitus, Type 1' 'Diabetic Retinopathy' OR 'Heart Disease' OR 'Cardiovascular Diseases' OR 'Peripheral Vascular Disease' OR "Amputation' OR 'Neuropathy."

RESULTS

All articles were retrospective with 51.1 % (n = 23) case control studies and 48.9 % (n = 22) cohort studies. 82.2 % (n = 37) examined simultaneous pancreas and kidney (SPK) transplantation and 17.8 % (n = 8) analysed pancreas transplant alone (PTA). Heterogenous outcomes metrics were employed. 15 studies examined diabetic retinopathy (DR) with 53.3 % (n = 8) demonstrated improvements after PT, while the remainder (n = 7) exhibited stabilisation. 16 studies assessed neuropathy and 87.5 % (n = 14) demonstrated beneficial effects of PT on nerve conduction studies, vibration perception threshold or corneal confocal microscopy. There was a positive effect on cardiovascular disease by reduction in the incidence of cardiac events, improvement in metabolic profile and increased left ventricular ejection fraction. 14 studies examined cardiovascular disease (71.4 % (n = 10) improvement; 14.2 % (n = 2) stabilisation; 14.2 % (n = 2) progression).

CONCLUSION

SPK and PTA have beneficial effects in ameliorating or stabilising diabetes complications. Future work should seek to reduce heterogeneity of outcome metrics assessing T1DM complication profile to facilitate robust comparison of beta-cell replacement interventions.

Effect of high-dose N-acetyl cysteine on the clinical outcome of patients with diabetic peripheral neuropathy: a randomized controlled study

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a vastly common and bothersome disorder with a clinically challenging course of treatment affecting patients with diabetes. This study aimed to evaluate the efficacy and safety of high dose oral N-acetyl cysteine (NAC) as adjuvant therapy on clinical outcome of DPN.

METHODS

A prospective, randomized, parallel, open label, controlled clinical trial. Ninety eligible DPN patients were randomly assigned to either control group receiving standard of care or NAC group receiving standard of care treatment and NAC at a dose of 2400 mg/day for 12 weeks. Glutathione peroxidase (GPx), nuclear factor erythoid-2 related factor (NRF-2) and tumor necrosis factor (TNF) were measured at baseline and after 12 weeks to assess anti-oxidant and anti-inflammatory properties. Michigan neuropathy screening instrument (MNSI), Toronto clinical neuropathy score (TCNS), Diabetic neuropathy score (DNS), Diabetes-39 quality of life questionnaire (DQOL) and pain score were assessed at baseline and after 12 weeks.

RESULTS

NAC group showed a significant increase (p < 0.05) in NRF-2 by 25.3% and GPx by 100% and a decline of 21.45% in TNF-alpha levels versus controls that reported a decline in NRF-2 and GPx and an increase in TNF-alpha. HgbA1C and AST levels significantly decreased in NAC versus controls (7.2 ± 1 vs 8 ± 1.1, p = 0.028 and 29.1 vs 55.4, p = 0.012) respectively. NAC administration resulted in a significant decline in MNSA, TCNS, DNS and pain scores versus controls that showed increase in all scores. The QOL total score and the anxiety and energy and mobility domain scores significantly decreased in the NAC group versus controls, p < 0.001.

CONCLUSION

High dose NAC administered for 12 weeks modulated inflammation by reducing TNF-alpha and increasing GPx and NRF2 versus controls. NAC improved clinical outcomes of DPN reflected by a decline in neuropathy and pain scores and an improvement in QOL.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04766450.

Vitamin D receptor FokI polymorphism as a risk factor for painful diabetic neuropathy in type 2 diabetes mellitus patients

Painful diabetic neuropathy (PDN) is a common complication in patients with type 2 diabetes mellitus (T2DM) with disruption of vitamin D (VD) activity as one of the risk factors. Active VD exerts its biological functions through the vitamin D receptor (VDR), which polymorphisms in the VDR gene can impair. This study aims to establish VDR FokI and ApaI polymorphisms as risk factors for PDN. This case-control study used samples from T2DM patients with and without PDN. Neuropathic pain was diagnosed using the DN4 questionnaire, while FokI and ApaI polymorphisms were examined using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method. Other factors examined included gender, hypertension, current insulin use, obesity, HbA1c levels, and dyslipidemia. A total of 64 subjects were involved in the study. The FokI polymorphism (CT+TT genotype) was a significant risk factor for PDN (OR 4.20; 95% CI [1.47-11.94]; p = 0.012). The T allele in the FokI polymorphism significantly increased the risk of PDN by 2.8 times (OR 2.78; 95% CI [1.28-6.01], p = 0.014). The ApaI polymorphism was not significantly associated with PDN. Diabetes duration ≥4.5 years and uncontrolled diabetes were other significant risk factors for PDN. Multivariate analysis identified three significant variables: FokI polymorphism (OR 5.00; 95% CI [1.37-18.24], p = 0.015), insulin use (OR 4.95; 95% CI [1.37-17.87], p = 0.015), and uncontrolled diabetes (OR 3.47; 95% CI [1.03-11.69], p = 0.045). The VDR FokI polymorphism with the T allele is a significant genetic risk factor for PDN in T2DM patients. The VDR ApaI polymorphism was not a significant risk factor for PDN.

Blood metabolomic profile in patients with type 2 diabetes mellitus with diabetic peripheral neuropathic pain

AIMS

This study aimed to identify metabolic markers for diabetic peripheral neuropathic pain (DPNP) in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Blood metabolite levels in the amino acid, biogenic amine, sphingomyelin, phosphatidylcholine (PC), carnitines, and hexose classes were analyzed in nondiabetic control (n = 27), T2DM without DPNP (n = 58), and T2DM with DPNP (n = 29) using liquid chromatography tandem mass spectrometry. Variable importance projection (VIP) evaluation by partial least squares discriminant analysis was performed on clinical parameters and metabolites.

RESULTS

Sixteen variables with VIP > 1.0 (P < 0.05) were identified across all patient groups, and 5 variables were identified to discriminate between the two T2DM groups. DPNP patients showed elevated fasting blood glucose, glutamate, PC aa C36:1, lysoPC a C18:1, and lysoPC a C18:2, while low-density lipoprotein cholesterol, phenylalanine, and tryptophan were reduced. Glutamate, lysoPC a C18:1, and lysoPC a C18:2 discriminated T2DM with DPNP from those without DPNP with an AUC of 0.671. The AUC was improved to 0.765 when ratios of metabolite pairs were considered.

INTERPRETATION

Blood metabolites include glutamate, and phospholipid-related metabolites implicated in neuropathic pain may have the potential as biomarkers for DPNP. Further investigation is required to understand the mechanism of action of these altered metabolites in DPNP.

Photobiomodulation therapy in diabetes: Benefits for pain relief, quality of life, and wound healing

Globally, 537 million people suffer from diabetes mellitus (DM), a condition often associated with sensory disturbances, wound development, and chronic pain, which significantly affects the quality of life and imposes a substantial economic burden. This study evaluated the effects of photobiomodulation (PBM) therapy on nociceptive and sensory changes in diabetic patients to understand pain manifestations and explore PBM's molecular mechanisms on wound healing. Twenty patients with type 2 DM underwent clinical assessments, completed pain and quality of life questionnaires, and had their pain sensitivity evaluated using the quantitative sensory test (QST). A 5 mm skin biopsy was taken for fibroblast culture. PBM therapy, using 660 nm red light, was administered twice weekly for 7 weeks on lower limb wounds. Results indicated that DM patients faced significant sensory impairments, impacting their quality of life. PBM therapy improved pain scores, alleviated neuropathic pain, and enhanced sensory function, leading to better quality of life and reduced anxiety and depression. It also accelerated wound healing, enhancing mobility and autonomy. In vitro studies showed PBM therapy increased cell proliferation through the ERK signaling pathway and modulation of matrix metalloproteinases (MMP-1/8 and 2) and tissue inhibitors of metalloproteinases (TIMP).

The global and regional burden of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is length-dependent peripheral nerve damage arising as a complication of type 1 or type 2 diabetes in up to 50% of patients. DPN poses a substantial burden on patients, who can experience impaired gait and loss of balance, predisposing them to falls and fractures, and neuropathic pain, which is frequently difficult to treat and reduces quality of life. Advanced DPN can lead to diabetic foot ulcers and non-healing wounds that often necessitate lower-limb amputation. From a socioeconomic perspective, DPN increases both direct health-care costs and indirect costs from loss of productivity owing to neuropathy-related disability. In this Review, we highlight the importance of understanding country-specific and region-specific variations in DPN prevalence to inform public health policy and allocate resources appropriately. We also explore how identification of DPN risk factors can guide treatment and prevention strategies and aid the development of health-care infrastructure for populations at risk. We review evidence that metabolic factors beyond hyperglycaemia contribute to DPN development, necessitating a shift from pure glycaemic control to multi-targeted metabolic control, including weight loss and improvements in lipid profiles.

An Overview on Diabetic Neuropathy

The term "Diabetic neuropathy" refers to a collection of clinical and subclinical symptoms caused by problems with the peripheral nervous system. Diabetes, which affects approximately 381 million people worldwide, is the source of dysfunction due to the emergence of microvascular complications. It is anticipated that in the next ten years, Diabetic neuropathy will manifest in about 50% of patients who are currently diagnosed with diabetes. Clinical diagnosis can be established by getting a thorough patient history and exploring the symptoms to rule out alternative causes. Although distal symmetrical polyneuropathy, or just, is the most common and well-researched variant of the disorder, this review will concentrate on it. The multifactorial pathogenesis is linked to various inflammatory, vascular, metabolic, and neurodegenerative illnesses. The three fundamental molecular alterations that lead to the development of diabetic neuropathic pain are oxidative stress, endothelial dysfunction, and chronic inflammation. These three elements are crucial in the development of polyneuropathy because their combination might result in direct axonal damage and nerve ischemia. The purpose of this article was to provide a narrative review of diabetic neuropathy. We provide an overview of the most recent data on biomarkers, the pathogenesis of the illness, the most recent epidemiology of diabetic neuropathy, and the existing screening and diagnosis outcome measures used in both clinical and research contexts.

12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes-2025

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.

Pharmacological Effects of Paeonia lactiflora Focusing on Painful Diabetic Neuropathy

Painful diabetic neuropathy (PDN) is a highly prevalent complication in patients suffering from diabetes mellitus. Given the inadequate pain-relieving effect of current therapies for PDN, there is a high unmet medical need for specialized therapeutic options. In traditional Chinese medicine (TCM), various herbal formulations have been implemented for centuries to relieve pain, and one commonly used plant in this context is Paeonia lactiflora (P. lactiflora). Here, we summarize the chemical constituents of P. lactiflora including their pharmacological mechanisms-of-action and discuss potential benefits for the treatment of PDN. For this, in silico data, as well as preclinical and clinical studies, were critically reviewed and comprehensively compiled. Our findings reveal that P. lactiflora and its individual constituents exhibit a variety of pharmacological properties relevant for PDN, including antinociceptive, anti-inflammatory, antioxidant, and antiapoptotic activities. Through this multifaceted and complex combination of various pharmacological effects, relevant hallmarks of PDN are specifically addressed, suggesting that P. lactiflora may represent a promising source for novel therapeutic approaches for PDN.

Prevalence of painful and painless diabetic peripheral neuropathy in the Northern Danish Region: A population-based study

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, yet varying estimates of its prevalence exist. The present study aimed to estimate a questionnaire-centered prevalence of painful and painless DPN in the Northern Danish Region, examine its geographical distribution within the region, and investigate associations between DPN and potential risk factors.

METHODS

A questionnaire-based survey was sent to all persons living with diabetes in the Northern Danish Region using electronic mail. Persons with diabetes were identified using The National Health Insurance Service Registry. The survey included information on demographics, socioeconomics, municipality, diabetes type, duration, and treatment, as well as the validated questionnaires Michigan Neuropathy Screening Instrument-questionnaire (MNSIq) and the Douleur Neuropathique en 4 Questions (DN4)-interview. Possible DPN was defined as an MNSIq-score ≥ 4, while possible painful DPN was defined as pain in both feet and a DN4-interview score ≥ 3.

RESULTS

A total of 23,206 eligible people were identified as having diabetes and approximately 33 % answered all questionnaires. The prevalence of possible DPN was 23.3 % (95 % CI: 22.4-24.3 %), while the prevalence of possible painful DPN was 18.0 % (17.1-18.8 %). The prevalence of possible DPN ranged from 22.1 % to 35.0 % between municipalities, while the prevalence of possible painful DPN ranged from 15.6 % to 20.0 %. High body-mass index, long diabetes duration, insulin use, glucagon-like-peptide-1-analogue use, and low income were associated with increased risk of DPN.

CONCLUSION

The high prevalence of possible painless and painful DPN emphasizes the need for better prevention and careful screening even in high-income countries.

Virtual Reality to Improve Sleep Quality in Patients Suffering from Painful Diabetic Polyneuropathy: A Proof of Concept Study

Background/Objectives: Sleep disturbance is often observed in the context of chronic pain. We hypothesize that, by providing an immersive Virtual Reality (VR) experience with a serious game to chronic pain patients an hour before bedtime, attention can be diverted from the pain condition, consequently leading to improved sleep quality. The aim is to evaluate the efficacy of VR compared to usual care in reducing the number of awakenings during the night and increasing sleep efficiency in patients suffering from painful diabetic polyneuropathy (PDPN). Methods: Eight patients with PDPN were randomized to either two weeks of VR or two weeks of usual care, followed by a cross-over. The primary outcome measurements were sleep efficiency and number of awakenings during the night. As secondary outcomes, self-reported sleep quality, insomnia, pain catastrophizing, anxiety, depression, pain intensity, side effects and impression of change were evaluated. Results: Data of seven patients were analysed. Actigraphy data, self-reported sleep quality, insomnia, pain catastrophizing, anxiety, depression and pain intensity scores did not differ between usual care and VR. As for impression of change, more patients improved after VR compared to usual care (V = 21, p = 0.03). Conclusions: A 2-week period of pain neuroscience education through VR did not result in increased sleep efficiency or fewer awakenings compared to usual care in patients with PDPN. These pilot results indicate that patients subjectively experience an improvement, yet this is not substantiated by either self-reported or objective measurements.

Acupuncture for the treatment of painful diabetic peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

A growing number of studies have investigated the efficacy of acupuncture in the treatment of painful diabetic peripheral neuropathy (PDPN), but the findings of these studies have generated conflicting results. This study therefore aimed to assess the efficacy of acupuncture for treating PDPN so as to offer more conclusive results.

METHODS

Seven databases were systematically searched for studies published up until December 1, 2023. All randomized controlled trials (RCTs) of acupuncture for PDPN with visual analog scale (VAS) for pain score were included. Study selection, data extraction, and evaluation were conducted independently by researchers. The Risk of Bias 2 (RoB2) tool was employed to assess the risk of bias. From this sample, the mean difference (MD), 95 % confidence intervals (CI), publication bias, and heterogeneity were then computed.

RESULTS

The manual acupuncture group exhibited a significant decrease in the VAS for pain score compared with the routine care group (p < 0.0001; MD = -1.45 [95 % CI, -1.97 to -0.93], I2 = 84 %). The real acupuncture group demonstrated a greater reduction in VAS scores than the sham acupuncture group (p = 0.004; MD = -0.97 [95 % CI, -1.63 to -0.31], I2 = 65 %). Additionally, the acupuncture group showed improvements in sensory nerve conduction velocity (SNCV, p < 0.0001; MD = 2.29 [95 % CI, 1.79 to 2.78], I2 = 14 %) as well as motor nerve conduction velocity (MNCV, p < 0.0001; MD = 2.87 [95 % CI, 2.46 to 3.27], I2 = 0). Different durations of acupuncture treatment, including 6-10 weeks and 3-4 weeks, demonstrated a significant reduction in VAS scores compared with the routine care group.

CONCLUSION

This meta-analysis provides preliminary evidence for the claim that acupuncture has the potential to alleviate PDPN symptoms and improve SNCV and MNCV. However, high-quality RCTs are needed to offer further evidence and thus better substantiate such a contention.

Analysis of risk factors for painful diabetic peripheral neuropathy and construction of a prediction model based on Lasso regression

Objective

To evaluate the prevalence and risk factors of painful diabetic peripheral neuropathy (PDPN) in patients with type 2 diabetic peripheral neuropathy (DPN) in Hunan Province, and establish and verify the prediction model.

Methods

This was a retrospective study involving 4908 patients, all patients were randomly divided into the training dataset(3436 cases)and the validation dataset (1472 cases) in a ratio of 7:3. Electroneurogram, clinical signs,and symptoms were used to evaluate neuropathy. Least absolute shrinkage and selection operator (LASSO) regression was used to select the optimal factors, and multifactorial logistic regression analysis was used to build a clinical prediction model. Calibration plots, decision curve analysis (DCA), and subject work characteristic curves (ROC) were used to assess the predictive effects.

Result

The prevalence of PDPN was 33.2%, and the multivariate logistic regression model showed that peripheral artery disease, duration of diabetes, smoking, and HBA1c were independent risk factors for PDPN in patients with type 2 diabetes. ROC analysis results showed that the AUC of the established prediction model was 0.872 in the training dataset and 0.843 in the validation dataset. The calibration curve and decision curve show that the model has good consistency and significant net benefit.

Conclusion

33.2% of DPN patients had PDPN in Hunan Province, China. Peripheral artery disease, duration of diabetes, smoking, and HBA1c are risk factors for PDPN in patients with type 2 diabetes. The prediction model is based on the above factors, which can well predict the probability of PDPN.

Nerve decompression for diabetic peripheral neuropathy with nerve entrapment: a narrative review

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes which primarily affects the sensory nervous system. Pain is the most common complaint that prompts patients to seek medical advice. With various presentations and intricate pathological mechanisms, diabetic peripheral neuropathic pain is currently the most crucial and challenging aspect of managing diabetic complications. As a heterogeneous disorder, there is no medication or treatment modality that is effective for all types of DPN and its associated neuropathic pain. Peripheral nerve decompression provides a new option for treating patients with diabetic peripheral neuropathic pain in the lower extremities. However, the clinical applicability of nerve decompression has been debated since it was first proposed. This review discusses the theoretical basis of nerve decompression, the clinical indications, and the progress of basic research based on the pathological mechanisms and nerve impairment patterns of diabetic peripheral neuropathic pain. The heterogeneity of DPN patients is summarized in terms of three aspects: complex pathophysiological mechanisms, multilevel nervous system involvement, and various nerve impairment properties. Identifying the presence of nerve entrapment among complex pathophysiological mechanisms is the key to successful outcomes. Tinel signs, focal pain, mechanical allodynia, and two-point discrimination were reported to be prognostic factors for good surgical outcomes, and their predictive ability might stem from their association with the early stage of entrapment neuropathy.

The Danish Centre for Strategic Research in Type 2 Diabetes (DD2) Project Cohort and Biobank from 2010 Through 2023-A Cohort Profile Update

Purpose

This paper provides an overview of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort and biobank, including baseline characteristics of participants enrolled up to 2023, and post-enrollment rates of cardiovascular disease outcomes and mortality.

Methods

Since 2010, the DD2 project has enrolled individuals with type 2 diabetes mellitus (T2DM) recently diagnosed by general practitioners and by hospital-based clinicians across Denmark. Data from questionnaires, clinical examinations, and biological samples are collected at enrollment. Additional baseline and longitudinal follow-up data are accessed via linkage to health registries.

Results

Between 2010 and 2023, the DD2 project enrolled 11,369 participants (41.3% women, median age 61.4 years). Median T2DM duration at enrollment was 1.3 years, and median BMI was 31.6 kg/m2 for women and 30.5 kg/m2 for men. 18.3% were smokers, 5.7% consumed more than 14/21 units of alcohol weekly (women/men), and 17.9% reported leisure-time physical inactivity. Original midwife records dating back >80 years revealed that 20.2% of cohort participants had birth weights <3000 g. Based on complete hospital contact history 10 years before enrollment, 20.7% of cohort participants had macrovascular complications, 17.0% had microvascular complications, and 21.7% had kidney disease based on eGFR or urine albumin-creatinine measurements. At enrollment, statins were used by 68.2%, antihypertensive drugs by 69.9%, and glucose-lowering drugs by 86.5% of individuals. Median HbA1c was 48 mmol/mol and median LDL cholesterol 2.2 mmol/L. Genome-wide genotyping and biomarker data have been analyzed for over 9000 individuals. During the current follow-up time from the enrollment date (median 7.9 years), incident cardiovascular disease rate has been 13.8 per 1000 person-years and the mortality rate has been 17.6 per 1000 person-years.

Conclusion

The DD2 cohort, with its detailed information and long-term follow up, can improve our understanding of the progression and prevention of complications among individuals with newly diagnosed T2DM.

Liquiritin ameliorates painful diabetic neuropathy in SD rats by inhibiting NLRP3-MMP-9-mediated reversal of aquaporin-4 polarity in the glymphatic system

Background

Despite advancements in diabetes treatment, the management of Painful Diabetic Neuropathy (PDN) remains challenging. Our previous research indicated a significant correlation between the expression and distribution of Aquaporin-4 (AQP4) in the spinal glymphatic system and PDN. However, the potential role and mechanism of liquiritin in PDN treatment remain uncertain.

Methods

This study established a rat model of PDN using a combination of low-dose Streptozotocin (STZ) and a high-fat, high-sugar diet. Rats were treated with liquiritin and MCC950 (an NLRP3 inhibitor). We monitored fasting blood glucose, body weight, and mechanical allodynia periodically. The glymphatic system's clearance function was evaluated using Magnetic Resonance Imaging (MRI), and changes in proteins including NLRP3, MMP-9, and AQP4 were detected through immunofluorescence and Western blot techniques.

Results

The rats with painful diabetic neuropathy (PDN) demonstrated several physiological changes, including heightened mechanical allodynia, compromised clearance function within the spinal glymphatic system, altered distribution of AQP4, increased count of activated astrocytes, elevated expression levels of NLRP3 and MMP-9, and decreased expression of AQP4. However, following treatment with liquiritin and MCC950, these rats exhibited notable improvements.

Conclusion

Liquiritin may promote the restoration of AQP4 polarity by inhibiting NLRP3 and MMP-9, thereby enhancing the clearance functions of the spinal cord glymphatic system in PDN rats, alleviating the progression of PDN.

Neuropathic Pain With and Without Diabetic Peripheral Neuropathy in Type 1 Diabetes

OBJECTIVE

Diabetic peripheral neuropathy (DPN) is common; however, the features and burden of neuropathic pain (NP) in type 1 diabetes (T1D) are poorly understood. We evaluated the incidence of first occurrence, annual prevalence, remission, and risk factors for NP during long-term follow-up of participants with T1D.

RESEARCH DESIGN AND METHODS

The Michigan Neuropathy Screening Instrument (MNSI) was administered annually (1994-2020) for 1,324 participants in the Epidemiology of Diabetes Interventions and Complications (EDIC) study. NP with clinical signs of DPN (NP DPN+) was defined according to self-reported NP plus an examination score >2, while NP without clinical signs of DPN (NP DPN-) was defined according to self-reported NP and an examination score ≤2.

RESULTS

At EDIC year 1, median age for participants was 36 years (interquartile range 30, 41), diabetes duration 13 years (10, 18), and HbA1c 7.9% (7.2, 8.9). At year 26 (median diabetes duration 39 years), cumulative incidence of NP was 57%, regardless of concomitant clinical signs of DPN (36% NP DPN+ vs. 46% NP DPN-). NP prevalence was 20% at 26 years (11% NP DPN+ and 9% NP DPN-), suggesting frequent remission. Annualized remission rates were similar regardless of pain medication use. In addition to HbA1c, female sex was associated with NP DPN-.

CONCLUSIONS

NP incidence in T1D was high and frequently occurred in the absence of clinical signs of neuropathy, as assessed with the MNSI. Pain remission was not explained by pain medication use. Effective clinical strategies for identification and management are needed.

Development and Progression of Polyneuropathy Over 5 Years in Patients With Type 2 Diabetes

BACKGROUND AND OBJECTIVES

There is a need for knowledge regarding the natural course of diabetic polyneuropathy (DPN), a complication in type 2 diabetes (T2D). The aim of this study was to examine the development of DPN over time.

METHODS

Patients with newly diagnosed T2D, recruited from a national cohort, and controls without diabetes of similar age and sex, underwent sensory phenotyping in 2016-2018. The Toronto consensus criteria were used to classify patients into possible, probable, and confirmed DPN. For this 5-year, observational, follow-up, cohort study, all participants were invited to a reexamination combining bedside sensory examination, quantitative sensory testing (QST), nerve conduction studies (NCSs), and skin biopsies measuring intraepidermal nerve fiber density (IENFD) in order to compare phenotypic and diagnostic changes over time.

RESULTS

Of the baseline 389 patients and 97 controls, 184 patients (median [interquartile range] diabetes duration 5.9 [4.1-7.4] years, mean hemoglobin A1c [HbA1c] 51 ± 11 mmol/mol at baseline) and 43 controls completed follow-up (46.9%). Confirmed DPN was present in 35.8% and 50.3%, probable DPN in 27.2% and 14.6%, possible DPN in 17.2% and 16.6%, and no DPN in 15.2% and 17.9% at baseline and follow-up, respectively. The estimated prevalence (95% CI) of confirmed DPN was 33.5% (24.9-42.1) compared with 22.7% (17.5-28.0) at baseline. During the follow-up period, 43.9% of patients with probable DPN developed confirmed DPN. Progression of neuropathy occurred in 16.5% and 24.7% and regression in 5.9% and 18.6% of patients based on NCS and IENFD, respectively. Progression based on NCS and/or IENFD was associated with higher baseline waist circumference and triglycerides, and regression with lower baseline HbA1c. Patients with at least probable DPN at baseline but neither patients without DPN nor controls developed increased spread of hyposensitivity, more hyposensitivity on QST and lower NCS z-scores at follow-up, and worsening of nerve parameters at follow-up correlated with higher baseline triglycerides.

DISCUSSION

In patients with well-regulated T2D, the proportion of patients with confirmed DPN increased over 5 years driven by progression from probable DPN. A large proportion of patients progressed, and a smaller proportion regressed on nerve parameters. Higher triglycerides correlated with this progression and may constitute a risk factor.

Lipid Levels and Risk of Diabetic Polyneuropathy in 2 Danish Type 2 Diabetes Cohorts

BACKGROUND AND OBJECTIVES

Reduction of blood lipids may aid in preventing diabetic polyneuropathy (DPN), but evidence remains conflicting. We investigated the association between lipid parameters and DPN risk in individuals with type 2 diabetes mellitus (T2DM).

METHODS

We conducted a population-based cohort study of individuals with newly diagnosed T2DM and a cross-sectional study using a clinically recruited T2DM cohort. Triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and non-HDL cholesterol were measured in routine diabetes care. Each lipid parameter was categorized according to the latest cutoffs in clinical guidelines on dyslipidemia. DPN was assessed with validated hospital diagnosis codes in the population-based cohort and with the Michigan Neuropathy Screening Instrument questionnaire in the clinical cohort. We calculated hazard ratios (HRs) using Cox regression and prevalence ratios (PRs) using Poisson regression.

RESULTS

We included 61,853 individuals in the population-based cohort (median age 63 [quartiles 54-72] years) and 4,823 in the clinical cohort (median age 65 [quartiles 57-72] years). The incidence rate of hospital-diagnosed DPN in the population-based cohort was 3.6 per 1000 person-years during a median follow-up of 7.3 years. Achieving guideline targets for HDL, LDL, and non-HDL cholesterol showed no association with DPN risk. By contrast, adjusted HRs (95% CI) for DPN were 1.02 (0.89-1.18) for triglyceride levels between 150 and 204 mg/dL (1.7-2.3 mmol/L) and 1.28 (1.13-1.45) for levels >204 mg/dL (2.3 mmol/L). In the clinical cohort with a DPN prevalence of 18%, DPN associated strongly with triglycerides >204 mg/dL (2.3 mmol/L) with an adjusted PR (95% CI) of 1.40 (1.21-1.62). The prevalence of DPN was modestly elevated for individuals with HDL cholesterol <39 mg/dL (1.0/1.3 mmol/L) in men and <50 mg/dL (1.3 mmol/L) in women (PR 1.13 [0.99-1.28]) and for individuals with non-HDL cholesterol >131 mg/dL (3.4 mmol/L) (PR 1.27 [1.05-1.52]). In both cohorts, spline models showed an increasing risk of DPN starting from triglyceride levels >124 mg/dL (1.4 mmol/L). All results were similar among statin users.

DISCUSSION

High triglyceride levels are a strong DPN risk factor. Future intervention studies shall determine whether triglyceride reduction is more important for DPN prevention than reduction of other lipids.

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.

Serum Spexin Level Is Negatively Associated With Peripheral Neuropathy and Sensory Pain in Type 2 Diabetes

Background: Spexin is a novel peptide hormone and has shown antinociceptive effects in experimental mice. This study is aimed at evaluating the association of serum spexin level with diabetic peripheral neuropathy (DPN) and related pain in a Chinese population. Methods: We enrolled 167 type 2 diabetes mellitus (T2DM) including 56 patients without DPN (non-DPN), 67 painless DPN, and 44 painful DPN. Serum spexin was measured using ELISA. Logistic regression models were performed to analyze the independent effects of spexin on prevalence of DPN and painful DPN. In streptozotocin (STZ)-induced diabetic mice, mechanical pain threshold was measured using electronic von Frey aesthesiometer. Human peripheral blood mononuclear cells (PBMCs) were isolated and further stimulated with lipopolysaccharide without or with spexin. The gene expression was assayed by qPCR. Results: Compared with non-DPN, serum spexin level decreased in painless DPN and further decreased in painful DPN. The odds of DPN was associated with low spexin level in T2DM, which was similar by age, sex, BMI, and diabetes duration, but attenuated in smokers. The odds of having pain was associated with decreased spexin level in DPN, which was similar by age, sex, smoking status, and diabetes duration, but attenuated in normal weight. Furthermore, we observed that mechanical pain threshold increased in spexin-treated diabetic mice. We also found that lipopolysaccharide treatment increased the mRNA level of TNF-α, IL-6, and MCP-1 in human PBMCs, while spexin treatment prevented this increase. Conclusions: These results suggested that spexin might serve as a protective factor for diabetes against neuropathology and pain-related pathogenesis.

The Mas-related G protein-coupled receptor d (Mrgprd) mediates pain hypersensitivity in painful diabetic neuropathy

ABSTRACT

Painful diabetic neuropathy (PDN) is one of the most common and intractable complications of diabetes. Painful diabetic neuropathy is characterized by neuropathic pain accompanied by dorsal root ganglion (DRG) nociceptor hyperexcitability, axonal degeneration, and changes in cutaneous innervation. However, the complete molecular profile underlying the hyperexcitable cellular phenotype of DRG nociceptors in PDN has not been elucidated. This gap in our knowledge is a critical barrier to developing effective, mechanism-based, and disease-modifying therapeutic approaches that are urgently needed to relieve the symptoms of PDN. Using single-cell RNA sequencing of DRGs, we demonstrated an increased expression of the Mas-related G protein-coupled receptor d (Mrgprd) in a subpopulation of DRG neurons in the well-established high-fat diet (HFD) mouse model of PDN. Importantly, limiting Mrgprd signaling reversed mechanical allodynia in the HFD mouse model of PDN. Furthermore, in vivo calcium imaging allowed us to demonstrate that activation of Mrgprd-positive cutaneous afferents that persist in diabetic mice skin resulted in an increased intracellular calcium influx into DRG nociceptors that we assess in vivo as a readout of nociceptors hyperexcitability. Taken together, our data highlight a key role of Mrgprd-mediated DRG neuron excitability in the generation and maintenance of neuropathic pain in a mouse model of PDN. Hence, we propose Mrgprd as a promising and accessible target for developing effective therapeutics currently unavailable for treating neuropathic pain in PDN.

Vitamin D deficiency increases the risk of diabetic peripheral neuropathy in elderly type 2 diabetes mellitus patients by predominantly increasing large-fiber lesions

AIMS

This study explores the link between Vitamin D deficiency (VDD) and diabetic peripheral neuropathy (DPN) in elderly type 2 diabetes mellitus (T2DM) patients.

METHODS

Involving 257 elderly T2DM patients, the study utilized propensity score matching to balance age, sex, and diabetes duration. VDD was defined as serum 25-hydroxyvitamin D [25(OH)D] levels below 20 ng/ml. Large nerve fiber lesions were evaluated by electromyogram, while small nerve fiber lesions were assessed by measuring skin conductance.

RESULTS

DPN patients had notably lower serum 25(OH)D levels than non-DPN patients [15.05 vs. 18.4 ng/ml, P = 0.018]. VDD was identified as an independent risk factor for DPN (odds ratio = 2.488, P = 0.008) in multivariate logistic regression analysis. Spearman's correlation showed negative correlations between serum 25(OH)D levels and specific nerve latencies, and positive correlations with specific nerve velocities and amplitudes. The VDD group exhibited longer median sensory nerve latencies and motor evoked potential latencies compared to the vitamin D-sufficient group. Further, VDD is associated with the prolongation of the median motor nerve latency (odds ratio = 1.362, P = 0.038).

CONCLUSIONS

VDD is independently associated with a higher risk of DPN. VDD may promote the development of DPN by affecting large nerve fibers.

Pramipexole protects against diabetic neuropathy: Effect on oxidative stress, TLR4/IRAK-1/TRAF-6/NF-κB and downstream inflammatory mediators

BACKGROUND

Diabetic neuropathy (DN) is a serious microvascular complication and a major cause of morbidity and mortality in diabetes mellitus. It is characterized by neurodegeneration of terminal sensory nerve fibers with subsequent pain, loss of sensation, and paresthesia, thus compromising the quality of life of diabetic patients. It is considered the leading cause of non-traumatic amputations worldwide, reflecting the insufficiency of current therapies. Pramipexole (PPX) is a dopamine receptor agonist used for the treatment of Parkinson's disease. The current study aims to investigate the potential neuroprotective effect of PPX in an experimental model of DN.

METHODS

Sprague Dawley rats were randomly assigned into five groups: normal control, Normal + PPX (1 mg/kg) group, STZ control, STZ + PPX (0.25 and 1 mg/kg/day for eight weeks). The neuroprotective effect of PPX in rats was evaluated in terms of sciatic nerve histological alterations, oxidative stress, and protein expression of TLR4/MyD88/IRAK-1/TRAF-6/NF-κB axis and downstream inflammatory mediators.

RESULTS

PPX administration ameliorated histopathological signs of neuronal inflammation and apoptosis. Additionally, PPX attenuated STZ-induced sciatic nerve oxidative stress and downregulated neural tissue expression of TLR4, MyD88, IRAK-1, TRAF-6, NF-κB and downstream mediators (TNF-α, IL-1β and ICAM-1).

CONCLUSION

Collectively, the current study sheds light on PPX as a potential protective medication to alleviate neuropathy progression in diabetic patients. PPX neuroprotective effect can be attributed to modulating TLR4/ MyD88/IRAK-1/TRAF-6/ NF-κB axis signaling in nerve tissues with subsequent attenuation of oxidative stress and inflammation.

Clinical observation of perioperative negative emotional changes in patients with percutaneous balloon compression for primary trigeminal neuralgia: A prospective cohort study

OBJECTIVE

To investigate the prevalence of negative emotions in trigeminal neuralgia (TN) patients, to identify risk factors associated with anxiety and depression, and further to explore the impact of percutaneous balloon compression (PBC) on anxiety and depression in TN patients during the perioperative period.

METHODS

400 patients with primary TN treated with PBC at our institution from November 2021 to April 2023 were included. We analyzed visual analogue scale (VAS) and the Hospital Anxiety and Depression Scale (HADS) scores. The patients' clinical data and short-term clinical outcomes were gathered and subjected to statistical analysis.

RESULTS

This study included a total of 400 patients diagnosed with primary TN. Patients who had high pain intensity (OR 1.20, 95 % CI 1.02-1.41; p = 0.025) or a history of multiple previous TN procedures (OR 1.49, 95 % CI 1.03-2.16; p = 0.036), were more prone to anxiety. Patients who were female (OR 1.59, 95 % CI 1.03-2.44; p = 0.036), had high pain intensity (OR 1.28, 95 % CI 1.08-1.52; p = 0.004) or had a history of multiple previous TN procedures (OR 1.48, 95 % CI 1.11-1.98; p = 0.008), were more likely to have depression. Significant improvements in anxiety and depressive symptoms were observed in patients who experienced pain relief after PBC (p < 0.001).

CONCLUSIONS

Female gender, high pain intensity, and a history of multiple prior TN procedures are associated risk factors for anxiety and depression in TN patients. PBC can provide patients with a high pain relief rate and significantly improve their anxiety and depression symptoms during the perioperative period.

Perineural injections of incobotulinumtoxin-A for diabetic neuropathic pain of the lower extremities: protocol for a phase II, single-centre, double-blind, randomised, placebo-controlled trial (the PINBOT study)

INTRODUCTION

Diabetic neuropathic pain (DNP) is a debilitating complication affecting 15-20% of people with diabetes and is a predictor of depression, poor sleep and decreased quality of life. Current pharmacological treatments are often insufficient and have significant side-effects. Subcutaneous or intradermal botulinumtoxin-A (BonT-A) is an effective and safe treatment for neuropathic pain but is limited by the need to cover the entire affected area with injections. For large cutaneous areas, infiltration of the sensory nerve supply with BonT-A could provide similar effects, with a single injection. We aim to investigate the safety, efficacy, and effects on quality of life, physical activity, depressive symptoms and activities of daily living of perineural injections of BonT-A in patients with DNP of both lower extremities.

METHODS

This study is a double-blind, randomised, placebo-controlled clinical trial. 80 participants with moderate to severe DNP of both legs will be randomised 1:1 to receive injections of either 100 units incobotulinumtoxin-A or a saline placebo around each distal sciatic nerve for two cycles of 12 weeks. Average daily pain scores will be recorded once a day from 1 week prior to the first treatment and through the entire study period. Primary outcomes are differences between groups in daily and weekly mean pain scores. Secondary outcomes are levels of physical activity, depression scores, health-related quality of life, activities of daily living, sensory profiles and motor function, recorded at baseline, 4, 12, 16 and 24 weeks. The use of rescue medication and adverse events will be recorded throughout the study period.

ETHICS AND DISSEMINATION

The study is approved by the Danish Committee on Health Research Ethics and the Danish Medicines Agency. EU-Clinical Trial Information System (EU: 2022-500727-68-01), clinicaltrials.gov (ID: NCT05623111). Results will be published in peer-reviewed journals in open-access formats and data made available in anonymised form.

TRIAL REGISTRATION NUMBER

NCT05623111.

Evaluating the effect of acupuncture on symptoms of diabetic peripheral neuropathy (DPN) among individuals with diabetic neuropathy: A single-blind, randomized trial study

Purpose

This study aimed to investigate the impact of acupuncture on Diabetic peripheral neuropathy (DPN) symptoms among individuals with diabetic neuropathy.

Methods

In a single-blind, randomized trial conducted between 2019 and 2020, 60 patients diagnosed with diabetic neuropathy were enrolled. These participants were randomly assigned to either the intervention or control group. The intervention group received real acupuncture alongside routine treatment once a week for seven sessions, each lasting 20 min. Meanwhile, the control group received sham acupuncture as an adjunct to their routine treatment, following the same schedule. To evaluate treatment efficacy, the study assessed primary outcomes, such as pain intensity measured using the Visual Analogue Scale (VAS). Secondary outcomes included evaluating fatigue severity and diabetic peripheral neuropathy (DPN) side effects, measured using the multidimensional fatigue inventory (MFI-20) and a standard questionnaire after each session.

Results

No statistically significant differences in pain and fatigue scores were observed between the two groups throughout all visits, even after adjusting for baseline characteristics, age, sex, type of diabetes, discopathy, and carpal tunnel syndrome parameters (P > 0.05). The findings did not provide strong evidence supporting a significant effect of real acupuncture compared to sham acupuncture on pain and fatigue values (P = 0.267 and 0.634, respectively). However, the 95% confidence interval for pain scores (-0.35, 1.28) was inconclusive, encompassing effect sizes favoring sham acupuncture.

Conclusion

Findings suggest that using acupuncture as an adjunctive therapy alongside routine treatment may not lead to a significant reduction in the symptoms of peripheral neuropathy and fatigue severity among individuals with diabetic neuropathy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01314-1.

Structural changes in Schwann cells and nerve fibres in type 1 diabetes: relationship with diabetic polyneuropathy

AIMS/HYPOTHESIS

Our aim was to investigate structural changes of cutaneous Schwann cells (SCs), including nociceptive Schwann cells (nSCs) and axons, in individuals with diabetic polyneuropathy. We also aimed to investigate the relationship between these changes and peripheral neuropathic symptoms in type 1 diabetes.

METHODS

Skin biopsies (3 mm) taken from carefully phenotyped participants with type 1 diabetes without polyneuropathy (T1D, n=25), type 1 diabetes with painless diabetic polyneuropathy (T1DPN, n=30) and type 1 diabetes with painful diabetic polyneuropathy (P-T1DPN, n=27), and from healthy control individuals (n=25) were immunostained with relevant antibodies to visualise SCs and nerve fibres. Stereological methods were used to quantify the expression of cutaneous SCs and nerve fibres.

RESULTS

There was a difference in the number density of nSCs not abutting to nerve fibres between the groups (p=0.004) but not in the number density of nSCs abutting to nerve fibres, nor in solitary or total subepidermal SC soma number density. The overall dermal SC expression (measured by dermal SC area fraction and subepidermal SC process density) and peripheral nerve fibre expression (measured by intraepidermal nerve fibre density, dermal nerve fibre area fraction and subepidermal nerve fibre density) differed between the groups (all p<0.05): significant differences were seen in participants with T1DPN and P-T1DPN compared with those without diabetic polyneuropathy (healthy control and T1D groups) (all p<0.05). No difference was found between participants in the T1DPN and P-T1DPN group, nor between participants in the T1D and healthy control group (all p>0.05). Correlational analysis showed that cutaneous SC processes and nerve fibres were highly associated, and they were weakly negatively correlated with different neuropathy measures.

CONCLUSIONS/INTERPRETATION

Cutaneous SC processes and nerves, but not SC soma, are degenerated and interdependent in individuals with diabetic polyneuropathy. However, an increase in structurally damaged nSCs was seen in individuals with diabetic polyneuropathy. Furthermore, dermal SC processes and nerve fibres correlate weakly with clinical measures of neuropathy and may play a partial role in the pathophysiology of diabetic polyneuropathy in type 1 diabetes.

Post hoc analysis of the SONAR trial indicates that the endothelin receptor antagonist atrasentan is associated with less pain in patients with type 2 diabetes and chronic kidney disease

Pain is prevalent among patients with diabetes and chronic kidney disease (CKD). The management of chronic pain in these patients is limited by nephrotoxicity of commonly used drugs including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. Since previous studies implicated endothelin-1 in pain nociception, our post hoc analysis of the SONAR trial assessed the association between the endothelin receptor antagonist atrasentan and pain and prescription of analgesics. SONAR was a randomized, double-blind, placebo-controlled clinical trial that recruited participants with type 2 diabetes and CKD (estimated glomerular filtration rate 25-75 ml/min/1.73 m2; urinary albumin-to-creatinine ratio 300-5000 mg/g). Participants were randomized to receive atrasentan or placebo (1834 each arm). The main outcome was pain-related adverse events (AEs) reported by investigators. We applied Cox regression to assess the effect of atrasentan compared to placebo on the risk of the first reported pain-related AE and, secondly, first prescription of analgesics. We used the Anderson-Gill method to assess effects on all (first and subsequent) pain-related AEs. During 2.2-year median follow-up, 1183 pain-related AEs occurred. Rates for the first pain-related event were 138.2 and 170.2 per 1000 person-years in the atrasentan and placebo group respectively (hazard ratio 0.82 [95% confidence interval 0.72-0.93]). Atrasentan also reduced the rate of all (first and subsequent) pain-related AEs (rate ratio 0.80 [0.70-0.91]). These findings were similar after accounting for competing risk of death (sub-hazard ratio 0.81 [0.71-0.92]). Patients treated with atrasentan initiated fewer analgesics including NSAIDs and opioids compared to placebo during follow-up (hazard ratio = 0.72 [0.60-0.88]). Thus, atrasentan was associated with reduced pain-related events and pain-related use of analgesics in carefully selected patients with type 2 diabetes and CKD.

Quality of life of persons with painful diabetic neuropathy: How can we improve it?

Painful diabetic neuropathy (PDN) is difficult to treat, with pharmacological treatments providing only partial pain relief that is limited by medication side effects. This necessitates a holistic approach to pain control,with pharmacological treatments supplemented by the management of psychosocial aspects of pain experience. Pain catastrophising and psychological flexibility are among the psychological constructs impacting persons' adaptation to PDN. While the former increases disability and reduces quality of life (QoL), the latter leads to less functional impairment and depression. Specific fears, and in particular, fear of falling, are significantly associated with pain-related disability and reduced QoL. The role of secondary parameters ofpain experience, including sleep and mood disturbancesas the potential guides to the selection of pharmacological treatmentsis yet to be established. Over the past decade there has been a steady increase in studies testing psychological interventions, including cognitive behavioural therapy and its several modifications, to manage pain in DN sufferers.Thesepilot and feasibility studies demonstrated the potential beneficial effects on pain severity and pain interference, depression and QoL in adults with PDN.Adequately powered trials are needed to confirm the effectiveness of these interventions in terms of pain experience and their impact on QoL.

The prevalence of anxiety in adult endocrinology outpatients: A systematic review and meta-analysis

INTRODUCTION

Anxiety disorders and anxiety symptoms are common mental disorders in the medically unwell and have significant impacts on patients' quality of life and engagement with psychiatric and medical services. Several systematic reviews have examined the prevalence of anxiety in specific endocrinology settings with estimates varying significantly from study to study. No meta-analysis has examined anxiety rates across the endocrinology outpatient setting. The aim of this meta-analysis is to provide endocrinologists with a precise estimate of the prevalence of anxiety - and impacting factors - in their outpatient clinics.

METHOD

PubMed, Embase, Cochrane and PsycINFO databases and Google Scholar were searched to identify studies that assessed anxiety prevalence in endocrinology outpatients published up to 23 January 2023. This was part of a larger systematic review search of anxiety prevalence in common medical outpatient clinics. Data characteristics were extracted independently by two investigators. Studies of patients 16 years and older and representative of the clinic were included. The point prevalence of anxiety or anxiety symptoms was measured using validated self-report questionnaires or structured interviews. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. Pooled estimates were analysed under the random-effects model and subgroup analyses on relevant variables were conducted under a mixed-effects model. Heterogeneity was assessed using the I2 statistic.

RESULTS

Fifty-nine studies with a total of 25,176 participants across 37 countries were included in this study. The overall pooled prevalence of anxiety or anxiety symptoms was 25·1% (95%CI 21·4-29·2; 6372/25,176; n = 59). Subgroup analyses revealed no difference in prevalence between outpatients with diabetes mellitus compared to other grouped endocrine disorders. Generalized Anxiety Disorder (GAD) was the most frequent clinical diagnosis 11·7% (95%CI 8·1-16·7; I2=87·93%; 443/4604; n = 17), while panic disorder was significantly higher in the non-diabetes group 9·5% (95%CI 5·9-14·9; I2=57·28%; 56/588; n = 8), compared to the diabetes group 5·2% (95%CI 3·7-7·3; I2=32·18%; 184/3669; n = 6). Estimates of prevalence were higher when assessed with a self-report scale 32·4% (95%CI 25·6-40·0; I2=96·06%; 1565/4675; n = 21) compared to diagnostic interview 17·6% (95%CI 12·2-24·7; I2=94·39%; 636/5168; n = 21). Outpatients in developing countries had higher rates of anxiety than those in developed countries. Female diabetes patients reported higher rates of anxiety compared to males.

CONCLUSION

Our study provides evidence that anxiety occurs frequently amongst endocrinology outpatients and at a higher rate than is estimated in the general population. Given the impact anxiety has on patient outcomes, it is important that effective management strategies be developed to support endocrinologists in identifying and treating these conditions in their outpatient clinics.

The pathogenesis of painful diabetic neuropathy and clinical presentation

Diabetic neuropathy is a common complication of diabetes that affects up to 50% of patients during the course of the disease; 20-30% of the patients also develop neuropathic pain. The mechanisms underlying neuropathy are not known in detail, but both metabolic and vascular factors may contribute to the development of neuropathy. The development of the most common type of neuropathy is insidious, often starting distally in the toes and feet and gradually ascending up the leg and later also involving fingers and hands. The symptoms are mainly sensory with either sensory loss or positive symptoms with different types of paresthesia or painful sensations. In more advanced cases motor dysfunction may occur, causing gait disturbances and falls. The diagnosis of neuropathy is based on history and a careful examination, which includes a sensory examination of both large and small sensory nerve fiber function, as well as an examination of motor function and deep tendon reflexes of the lower limbs. Attention needs to be paid to the feet including examination of the skin, joints, and vascular supply. Nerve conduction studies are rarely needed to make a diagnosis of neuropathy. In patients with clear motor deficit or with an asymmetrical presentation, additional electrophysiological examination may be necessary. Early detection of diabetic neuropathy is important to avoid further irreversible injury to the peripheral nerves.

BTD: A TRPC5 activator ameliorates mechanical allodynia in diabetic peripheral neuropathic rats by modulating TRPC5-CAMKII-ERK pathway

Mechanical allodynia is a serious complication of painful diabetic neuropathy (PDN) with limited treatment options. The transient receptor potential canonical 5 (TRPC5) channel is a promising target in pain; however, its role in painful diabetic neuropathy has not yet been elucidated. In this study, we have investigated the role of TRPC5 channels using BTD [N-{3-(adamantan-2-yloxy)-propyl}-3-(6-methyl-1,1-dioxo-2H-1λ6,2,4-benzothiadiazin-3-yl)-propanamide)],a potent TRPC5 activator and HC070, as TRPC5 channel inhibitor in rat model of PDN. In this study, streptozotocin was used to induce diabetes in male Sprague-Dawley rats. The alterations in mechanical and thermal pain thresholds, nerve functional deficits in diabetic animals were assessed by various behavioral and functional parameters.TRPC5 involvement was investigated by treating neuropathic rats with BTD, TRPC5 channel activator (1 and 3 mg/kg, i.p. for 14 days) and HC070, a TRPC5 channel inhibitor (1 and 3 mg/kg). BTD and HC070 effects in pain reduction were assessed by western blotting, estimating oxidative stress and inflammatory markers in the lumbar spinal cord. BTD treatment (3 mg/kg, i.p.) once daily for 14 days ameliorated mechanical allodynia but not thermal hyposensation or nerve functional deficit in diabetic neuropathic rats. BTD treatment down-regulated TRPC5 expression by increasing the activity of protein kinase C. It also subsequently down-regulated the downstream pain markers (CAMKII, ERK) in the spinal cord. Additionally, a decrease in inflammatory cytokines (TNF-α, IL-6) also demonstrated BTD's potent anti-inflammatory properties in reducing mechanical allodynia. On the other hand, HC070 did not exert any beneficial effects on behavioural and nerve functional parameters. The study concludes that BTD ameliorated mechanical allodynia in a rat model of painful diabetic neuropathy not only through modulation of the TRPC5-CAMKII-ERK pathway but also through its anti-inflammatory and anti-apoptotic properties. Overall, BTD is a promising therapeutic molecule in the treatment of mechanical allodynia in painful diabetic neuropathy.

Prevalence and risk factors of diabetic peripheral neuropathy: A population-based cross-sectional study in China

AIMS

To assess the prevalence of diabetic peripheral neuropathy (DPN) and its risk factors in the type 2 diabetes mellitus (T2DM) population.

METHODS

This cross-sectional study enroled patients with T2DM between July and December 2017 from 24 provinces in China. Diabetic peripheral neuropathy and its severity were assessed by the Toronto clinical scoring system, neuropathy symptoms score (NSS) and neuropathy disability score. The prevalence of DPN and its risk factors were analysed.

RESULTS

A total of 14,908 patients with T2DM were enroled. The prevalence of DPN was 67.6%. Among 10,084 patients with DPN, 4808 (47.7%), 3325 (33.0%), and 1951 (19.3%) had mild, moderate, and severe DPN, respectively. The prevalence of DPN in females was higher than in males (69.0% vs. 66.6%, P = 0.002). The prevalence of DPN increased with age and course of diabetes and decreased with body mass index (BMI) and education level (all P for trend <0.05). The comorbidities and complications in patients with DPN were higher than in those without DPN, including hypertension, myocardial infarction, diabetic retinopathy, and diabetic nephropathy (all P < 0.001). Age, hypertension, duration of diabetes, diabetic retinopathy, diabetic nephropathy, glycated haemoglobin, high-density lipoprotein cholesterol, and lower estimated glomerular filtration rate were positively associated with DPN, while BMI, education level, fasting C-peptide, and uric acid were negatively associated with DPN.

CONCLUSIONS

Among patients with T2DM in China, the prevalence of DPN is high, especially in the elderly, low-income, and undereducated patients.

Analysis of Japanese nationwide health datasets: association between lifestyle habits and prevalence of neuropathic pain and fibromyalgia with reference to dementia-related diseases and Parkinson's disease

OBJECTIVES

Chronic pain is defined as pain that persists or recurs for more than 3 months. This study focuses on neuropathic pain (NP) and fibromyalgia (FM) which are chronic pain states, and aims to identify lifestyle habits associated with their prevalence. Other neurological disorders are also analyzed as references.

METHODS

Association between the variable referring to disease prevalence (number of claims for reimbursement of marker drugs) and the variable for lifestyle habits/health examination results (collected from insured individuals aged 40-74 years) was determined by analyzing Japanese nationwide datasets, which were collected in 2018 and aggregated by prefecture. Pregabalin, donepezil, and levodopa were used as marker drugs for the chronic pain states, dementia-related diseases (Alzheimer's disease and Lewy body dementia) and Parkinson's disease (PD), respectively. Pearson's correlation analysis and multiple linear regression analysis were conducted.

RESULTS

Variables showing correlation coefficient (|r|)>0.5 were put into the multiple linear regression. Exercise habits (ꞵ=-0.3182), smoking habits (0.3218), daily drinking (0.2683), and alanine aminotransferase>51 U/L (0.2309) were finally incorporated in the equation for pregabalin (R 2=0.7268). Walking speed (-0.4543) and daily drinking (0.5077) were incorporated in the equation for donepezil (R 2=0.5718).

CONCLUSIONS

The prevalence of chronic pain states is associated with lifestyle habits, just like the dementia-related diseases. Exercise in daily life is negatively associated with the prevalence of the chronic pain states, although excessive alcohol drinking, smoking, and high serum ALT are positively associated with it. The prevalence of PD seems less associated with lifestyle habits.

Diabetic Neuropathies

OBJECTIVE

This article provides an up-to-date review of the diagnosis and management of the most common neuropathies that occur in patients with diabetes.

LATEST DEVELOPMENTS

The prevalence of diabetes continues to grow worldwide and, as a result, the burden of diabetic neuropathies is also increasing. Most diabetic neuropathies are caused by hyperglycemic effects on small and large fiber nerves, and glycemic control in individuals with type 1 diabetes reduces neuropathy prevalence. However, among people with type 2 diabetes, additional factors, particularly metabolic syndrome components, play a role and should be addressed. Although length-dependent distal symmetric polyneuropathy is the most common form of neuropathy, autonomic syndromes, particularly cardiovascular autonomic neuropathy, are associated with increased mortality, whereas lumbosacral radiculoplexus neuropathy and treatment-induced neuropathy cause substantial morbidity. Recent evidence-based guidelines have updated the recommended treatment options to manage pain associated with distal symmetric polyneuropathy of diabetes.

ESSENTIAL POINTS

Identifying and appropriately diagnosing the neuropathies of diabetes is key to preventing progression. Until better disease-modifying therapies are identified, management remains focused on diabetes and metabolic risk factor control and pain management.

Gut microbiota modulate distal symmetric polyneuropathy in patients with diabetes

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

Structural Changes of Cutaneous Immune Cells in Patients With Type 1 Diabetes and Their Relationship With Diabetic Polyneuropathy

BACKGROUND AND OBJECTIVES

Diabetic polyneuropathy (DPN) is a complication of diabetes characterized by pain or lack of peripheral sensation, but the underlying mechanisms are not yet fully understood. Recent evidence showed increased cutaneous macrophage infiltration in patients with type 2 diabetes and painful DPN, and this study aimed to understand whether the same applies to type 1 diabetes.

METHODS

The study included 104 participants: 26 healthy controls and 78 participants with type 1 diabetes (participants without DPN [n = 24], participants with painless DPN [n = 29], and participants with painful DPN [n = 25]). Two immune cells, dermal IBA1+ macrophages and epidermal Langerhans cells (LCs, CD207+), were visualized and quantified using immunohistological labeling and stereological counting methods on skin biopsies from the participants. The IBA1+ macrophage infiltration, LC number density, LC soma cross-sectional area, and LC processes were measured in this study.

RESULTS

Significant difference in IBA1+ macrophage expression was seen between the groups (p = 0.003), with lower expression of IBA1 in participants with DPN. No differences in LC morphologies (LC number density, soma cross-sectional area, and process level) were found between the groups (all p > 0.05). In addition, IBA1+ macrophages, but not LCs, correlated with intraepidermal nerve fiber density, Michigan neuropathy symptom inventory, (questionnaire and total score), severity of neuropathy as assessed by the Toronto clinical neuropathy score, and vibration detection threshold in the whole study cohort.

DISCUSSION

This study showed expressional differences of cutaneous IBA1+ macrophages but not LC in participants with type 1 diabetes-induced DPN compared with those in controls. The study suggests that a reduction in macrophages may play a role in the development and progression of autoimmune-induced diabetic neuropathy.

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

BACKGROUND AND AIMS

Cardiovascular autonomic neuropathy (CAN) in patients with diabetes is associated with poor prognosis. We aimed to assess signs of CAN and autonomic symptoms and to investigate the impact of sensorimotor neuropathy on CAN by examining type 2 diabetes patients with (DPN [distal sensorimotor polyneuropathy]) and without distal sensorimotor polyneuropathy (noDPN) and healthy controls (HC). Secondarily, we aimed to describe the characteristics of patients with CAN.

METHODS

A population of 374 subjects from a previously described cohort of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) were included. Subjects were examined with the Vagus™ device for the diagnosis of CAN, where two or more abnormal cardiovascular autonomic reflex tests indicate definite CAN. Autonomic symptoms were assessed with Composite Autonomic Symptom Score 31 (COMPASS 31) questionnaire. DPN was defined according to the Toronto consensus panel definition.

RESULTS

Definite CAN was present in 22% with DPN, 7% without DPN and 3% of HC, and 91% of patients with definite CAN had DPN. Patients with DPN and definite CAN reported higher COMPASS 31 scores compared to patients with noDPN (20.0 vs. 8.3, p < 0.001) and no CAN (22.1 vs. 12.3, p = 0.01). CAN was associated with HbA1c and age in a multivariate logistic regression analysis but was not associated with IEFND or triglycerides.

INTERPRETATION

One in five patients with DPN have CAN and specific CAN characteristics may help identify patients at risk for developing this severe diabetic complication. Autonomic symptoms were strongly associated with having both DPN and CAN, but too unspecific for diagnosing CAN.

Efficacy of Pregabalin and Duloxetine in Patients with Painful Diabetic Peripheral Neuropathy (PDPN): A Multi-Centre Phase IV Clinical Trial-BLOSSOM

INTRODUCTION

Our trial (ClinicalTrials.gov Identifier: NCT04246619) evaluates the efficacy of two generic medications, pregabalin and duloxetine, for treating pain in PDPN patients.

METHODS

The patients were randomised either into the pregabalin (99) or the duloxetine (102) arm. Pain was evaluated using the DN-4 questionnaire, and visual analogue scales (VASs, 0-100 mm) were used to measure the average pain intensity (API), worst pain intensity (WPI) in the last 24 h and current pain intensity (CPI).

RESULTS

The proportion of patients with a clinically significant improvement in the API at Week 12 was 88.3% [CI 81.7%, 94.8%] in the pregabalin arm and 86.9% [CI 76.7%, 97.1%] in the duloxetine arm. After 12 weeks, the CPI, API, and WPI decreased by -35.3 [-40.5, -30.0], -37.0 [-41.4, -32.6], and -41.6 [-46.6, -36.5] in the pregabalin arm, and by -35.0 [-39.2, -30.7], -36.9 [-41.5, -32.3], and -40.0 [-44.8, -35.2] in the duloxetine arm (all in mm, all p < 0.001).

CONCLUSION

Our results demonstrate that pregabalin and duloxetine are effective medications for treating pain in PDPN in more than 86% of all randomised patients.

Painful Diabetic Peripheral Neuropathy - A Survey of Patient Experiences

Purpose

An online survey was conducted in the USA to obtain information about the knowledge and experiences of patients with painful diabetic peripheral neuropathy (pDPN).

Patients and Methods

506 adults with diabetes and pDPN affecting the feet for ≥6 months, for which pain medication had been prescribed for ≥6 months, completed an online survey questionnaire in March 2021.

Results

79% of respondents had type 2 diabetes, 60% were male, 82% were Caucasian and 87% had comorbidities. Pain was significant to severe in 49% of respondents, and 66% had disability due to nerve pain. Anticonvulsants, over-the-counter pills and supplements were the most commonly used medications. Topical creams/patches were prescribed in 23% of respondents. 70% had tried multiple medications for their pain. 61% of respondents had to see ≥2 doctors before receiving a correct diagnosis of pDPN. 85% of respondents felt that the doctor understood their pain and its impact on their life. 70% had no difficulty finding the information they wanted. 34% felt insufficiently informed about their condition. A medical professional was the primary, and most trusted, source of information. Frustration, worry, anxiety and uncertainty were the most commonly reported emotions. Respondents were generally eager to find new medications for pain relief and desperate for a cure. Lifestyle changes because of nerve pain were most commonly associated with physical disabilities and sleep disturbance. Better treatments and freedom from pain were the overriding perspectives when considering the future.

Conclusion

Patients with pDPN are generally well informed about their pain and trust their doctor but remain unsatisfied with their current treatment and struggle to find a lasting solution for their pain. Early identification and diagnosis of pain in diabetics, and education about treatments, is important to minimize the impact of pain on quality of life and emotional well-being.

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.

Assessing Corneal Confocal Microscopy and Other Small Fiber Measures in Diabetic Polyneuropathy

BACKGROUND AND OBJECTIVES

Damage to small nerve fibers is common in diabetic polyneuropathy (DPN), and the diagnosis of DPN relies on subjective symptoms and signs in a combination with objective confirmatory tests, typically electrophysiology or intraepidermal nerve fiber density (IENFD) from skin biopsy. Corneal confocal microscopy (CCM) has been introduced as a tool to detect DPN. However, it is unclear if CCM can reliably be used to diagnose DPN and how the technique compares with other commonly used measures of small fiber damage, such as IENFD, cold detection threshold (CDT), and warm detection threshold (WDT). Therefore, we assessed and compared the use of CCM, IENFD, CDT, and WDT in the diagnosis of DPN in patients with type 2 diabetes.

METHODS

In this cohort study, the participants underwent detailed neurologic examination, electrophysiology, quantification of IENFD, CCM, and quantitative sensory testing. Definition of DPN was made in accordance with the Toronto criteria for diabetic neuropathy (without relying on IENFD and thermal thresholds).

RESULTS

A total of 214 patients with at least probable DPN, 63 patients without DPN, and 97 controls without diabetes were included. Patients with DPN had lower CCM measures (corneal nerve fiber length [CNFL], nerve fiber density, and branch density), IENFD, CDT, and WDT compared with patients without DPN (p ≤ 0.001, <0.001, 0.002, p < 0.001, p = 0.003, and <0.005, respectively), whereas there was no difference between controls and patients with diabetes without DPN. All 3 CCM measures showed a very low diagnostic sensitivity with CNFL showing the highest (14.4% [95% CI 9.8-18.4]) and a specificity of 95.7% (88.0-99.1). In comparison, the sensitivity of abnormal CDT and/or WDT was 30.5% (24.4-37.0) with a specificity of 84.9% (74.6-92.2). The sensitivity of abnormal IENFD was highest among all measures with a value of 51.1% (43.7-58.5) and a specificity of 90% (79.5-96.2). CCM measures did not correlate with IENFD, CDT/WDT, or neuropathy severity in the group of patients with DPN.

DISCUSSION

CCM measures showed the lowest sensitivity compared with other small fiber measures in the diagnosis of DPN. This indicates that CCM is not a sensitive method to detect DPN in recently diagnosed type 2 diabetes.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that CCM measures aid in the detection of DPN in recently diagnosed type 2 diabetics but with a low sensitivity when compared with other small fiber measures.

Excitatory and inhibitory neuronal signaling in inflammatory and diabetic neuropathic pain

Pain, although unpleasant, is an essential warning mechanism against injury and damage of the organism. An intricate network of specialised sensors and transmission systems contributes to reception, transmission and central sensitization of pain. Here, we briefly introduce some of the main aspects of pain signal transmission, including nociceptors and nociceptive signals, mechanisms of inflammatory and neuropathic pain, and the situation of diabetes-associated neuropathic pain. The role of glia-astrocytes, microglia, satellite glia cells-and their specific channels, transporters and signaling pathways is described. A focus is on the contribution of inhibitory synaptic signaling to nociception and a possible role of glycine receptors in glucose-mediated analgesia and treatment-induced diabetic neuropathy. Inhibitory receptors such as GABA_A- and glycine receptors are important contributors to nociceptive signaling; their contribution to altered pain sensation in diabetes may be of clinical relevance, and they could be promising therapeutic targets towards the development of novel analgesics.

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.

Training and External Validation of a Predict Nomogram for Type 2 Diabetic Peripheral Neuropathy

Background: Diabetic peripheral neuropathy (DPN) is a critical clinical disease with high disability and mortality rates. Early identification and treatment of DPN is critical. Our aim was to train and externally validate a prediction nomogram for early prediction of DPN. Methods: 3012 patients with T2DM were retrospectively studied. These patients were hospitalized between 1 January 2017 and 31 December 2020 in the First Affiliated Hospital of Xinjiang Medical University in Xinjiang, China. A total of 901 patients with T2DM from the Suzhou BenQ Hospital in Jiangsu, China who were hospitalized between 1 January 2019 and 31 December 2020 were considered for external validation. The least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression were performed to identify independent predictors and establish a nomogram to predict the occurrence of DPN. The performance of the nomogram was evaluated using a receiver operating characteristic curve (ROC), a calibration curve, and a decision curve analysis (DCA). Findings: Age, 25-hydroxyvitamin D3 [25(OH)D3], Duration of T2DM, high-density lipoprotein (HDL), hemoglobin A1c (HbA1c), and fasting blood glucose (FBG) were used to establish a nomogram model for predicting the risk of DPN. In the training and validation cohorts, the areas under the curve of the nomogram constructed from the above six factors were 0.8256 (95% CI: 0.8104–0.8408) and 0.8608 (95% CI: 0.8376–0.8840), respectively. The nomogram demonstrated excellent performance in the calibration curve and DCA. Interpretation: This study has developed and externally validated a nomogram model which exhibits good predictive ability in assessing DPN risk among the type 2 diabetes population. It provided clinicians with an accurate and effective tool for the early prediction and timely management of DPN.

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.