Healthcare utilization and costs in diabetes relative to the clinical spectrum of painful diabetic peripheral neuropathy

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

Background/aim

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

Materials and methods

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

Results

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

Conclusion

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

10-kHz spinal cord stimulation treatment for painful diabetic neuropathy: results from post-hoc analysis of the SENZA-PPN study

Aim: Previous studies of 10 kHz spinal cord stimulation demonstrated its safety and efficacy for treatment of neuropathic pain of the trunk and/or limbs. This study analyzed data from a subset of subjects with painful diabetic neuropathy enrolled in a prospective, multicenter study of peripheral polyneuropathy with various etiologies. Materials & methods: Of the eight subjects that had permanent devices, seven attended the 12-month follow-up assessment. Results & conclusion: At 12 months, 6/7 subjects were treatment responders (≥50% pain relief) and had pain remission (visual analog scale ≤ 3.0 cm). Worsening of neurologic deficits was not reported in any subject. Instead, 5/7 subjects showed improvements in sensory testing and/or reflexes. These results support further investigation of 10 kHz spinal cord stimulation as a safe and effective treatment for intractable painful diabetic neuropathy.

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.

Relationship between diabetic polyneuropathy, serum visfatin, and oxidative stress biomarkers

BACKGROUND

Diabetic polyneuropathy is a very common complication of diabetes. Numerous studies are available in terms of pathogenesis. But examination methods with low reliability are still not standardized and generally time consuming. High-sensitive, easy-to-access methods are expected. Biochemical markers are one of the subjects of research. We aimed to discover a potential biomarker that can be used for this purpose in patients with diabetes who have not yet developed symptoms of neuropathy.

AIM

To determine the place and availability of visfatin and thiol-disulfide homeostasis in this disorder.

METHODS

A total of 392 patients with type 2 diabetes mellitus were included in the study. The polyneuropathy clinical signs were evaluated with the Subjective Peripheral Neuropathy Screen Questionnaire and Michigan Neuropathy Screening Instrument questionnaire and examination. The biochemical parameters, oxidative stress markers, visfatin, and thiol-disulfide homeostasis were analyzed and correlated with each other and clinical signs.

RESULTS

Subjective Peripheral Neuropathy Screen Questionnaire and Michigan Neuropathy Screening Instrument questionnaire with examination scores were correlated with each other and diabetes duration (P < 0.005). Neuropathy related symptoms were present in 20.7% of the patients, but neuropathy related findings were observed in 43.9% of the patients. Serum glucose, glycated hemoglobin, and visfatin were positively correlated with each other. Also, these parameters were positively correlated with the total oxidative stress index. Total and native thiol was positively correlated with total antioxidant status and negatively with oxidant status. Inversely thiol-disulfide positively correlated with higher glucose and oxidant status and negatively with total antioxidant status (P < 0.005). There was no correlation between visfatin and thiol-disulphide (P = 0.092, r = 0.086). However, a significant negative correlation was observed between visfatin and total with native thiol (P < 0.005, r = -0.338), (P < 0.005, r = -0.448).

CONCLUSION

Diagnosis of neuropathy is one of the issues studied in patients with diabetes. Visfatin and thiol-disulfide balance were analyzed for the first time in this study with inspiring results.

Risk Factors for Diabetic Peripheral Neuropathy and Cardiovascular Autonomic Neuropathy in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study

The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study demonstrated that intensive glucose control reduced the risk of developing diabetic peripheral neuropathy (DPN) and cardiovascular autonomic neuropathy (CAN). We evaluated multiple risk factors and phenotypes associated with DPN and CAN in this large, well-characterized cohort of participants with type 1 diabetes, followed for >23 years. DPN was defined by symptoms, signs, and nerve conduction study abnormalities in ≥2 nerves; CAN was assessed using standardized cardiovascular reflex tests. Generalized estimating equation models assessed the association of DPN and CAN with individual risk factors measured repeatedly. During DCCT/EDIC, 33% of participants developed DPN and 44% CAN. Higher mean HbA1c was the most significant risk factor for DPN, followed by older age, longer duration, greater height, macroalbuminuria, higher mean pulse rate, β-blocker use, and sustained albuminuria. The most significant risk factor for CAN was older age, followed by higher mean HbA1c, sustained albuminuria, longer duration of type 1 diabetes, higher mean pulse rate, higher mean systolic blood pressure, β-blocker use, estimated glomerular filtration rate <60 mL/min/1.73 m2, higher most recent pulse rate, and cigarette smoking. These findings identify risk factors and phenotypes of participants with diabetic neuropathy that can be used in the design of new interventional trials and for personalized approaches to neuropathy prevention.

(Cost-)effectiveness of lower extremity nerve decompression surgery in subjects with diabetes: the DeCompression (DECO) trial-study protocol for a randomised controlled trial

INTRODUCTION

The peripheral nerves of patients with diabetes are often pathologically swollen, which results in entrapment at places of anatomical narrowing. This results in nerve dysfunction. Surgical treatment of compression neuropathies in the lower extremities (lower extremity nerve decompression (LEND)) results in relief of symptoms and gain in peripheral nerve function, which may lead to less sensory loss (short term) and less associated detrimental effects including foot ulceration and amputations, and lower costs (long term). The aim of the DeCompression trial is to evaluate the effectiveness and (cost-)effectiveness of surgical decompression of compressed lower extremity nerves (LEND surgery) compared with patients treated with conventional (non-surgical) care.

METHODS AND ANALYSIS

A stratified randomised (1 to 1) controlled trial comparing LEND surgery (intervention) with conventional non-surgical care (control strategy) in subjects with diabetes with problems of neuropathy due to compression neuropathies in the lower extremity. Randomisation is stratified for participating hospital (n=11) and gender. Patients and controls have the same follow-up at 1.5, 3, 6, 9, 12, 18, 24 and 48 months. Participants (n=344) will be recruited in 12 months and enrolled in all affiliated hospitals in which they receive both the intervention or conventional non-surgical care and follow-up. Outcome assessors are blinded to group assignment.

PRIMARY OUTCOME

disease-specific quality of life (Norfolk Quality of Life Questionnaire-Diabetic Neuropathy).

SECONDARY OUTCOMES

health-related quality of life (EuroQoL 5-dimension 5-level (EQ-5D5L), 36-item Short Form (SF-36)), plantar sensation (Rotterdam Diabetic Foot Test Battery), incidence of ulcerations/amputations, resource use and productivity loss (Medical Cost Questionnaire, Productivity Cost Questionnaire) during follow-up. The incremental cost-effectiveness ratio will be estimated on the basis of the collected empirical data and a cost-utility model.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Medical Research Ethics Committee of Utrecht University Medical Center (reference: NL68312.041.19v5, protocol number: 19-335/M). Dissemination of results will be via journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NetherlandsTrial Registry NL7664.

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.

Challenges of neuropathic pain: focus on diabetic neuropathy

Neuropathic pain is a frequent condition caused by a lesion or disease of the central or peripheral somatosensory nervous system. A frequent cause of peripheral neuropathic pain is diabetic neuropathy. Its complex pathophysiology is not yet fully elucidated, which contributes to underassessment and undertreatment. A mechanism-based treatment of painful diabetic neuropathy is challenging but phenotype-based stratification might be a way to develop individualized therapeutic concepts. Our goal is to review current knowledge of the pathophysiology of peripheral neuropathic pain, particularly painful diabetic neuropathy. We discuss state-of-the-art clinical assessment, validity of diagnostic and screening tools, and recommendations for the management of diabetic neuropathic pain including approaches towards personalized pain management. We also propose a research agenda for translational research including patient stratification for clinical trials and improved preclinical models in relation to current knowledge of underlying mechanisms.

Treatment of diabetic peripheral neuropathy: a review

OBJECTIVES

This review surveys current pharmacotherapies available for the treatment of diabetic peripheral neuropathy (DPN), emphasising their mechanisms of action.

METHODS

A comprehensive literature review focusing on the 'pharmacotherapy and treatment of diabetic peripheral neuropathy' was conducted. The Database of International Pharmaceutical Abstracts, EMBASE, PubMed, OVID, Scopus, Google and Google Scholar were searched, and reference lists of relevant articles were also included.

KEY FINDINGS

Diabetic peripheral neuropathy is often inadequately treated, and the role of improving glycaemic control specifically in type-2 diabetes remains unclear. It is crucial to explore the mechanisms of action and effectiveness of available therapies. Major international clinical guidelines for the management of DPN recommend several symptomatic treatments. First-line therapies include tricyclic antidepressants, serotonin-noradrenaline reuptake inhibitors, and anticonvulsants that act on calcium channels. Other therapies include opioids and topical agents such as capsaicin and lidocaine. The objectives of this paper are to review current guidelines for the pharmacological management of DPN and to discuss research relevant to the further development of pharmacological recommendations for the treatment of diabetic neuropathy.

SUMMARY

Diabetic neuropathy is a highly prevalent, disabling condition, the management of which is associated with significant costs. Evidence supports the use of specific anticonvulsants and antidepressants for pain management in patients with diabetic peripheral neuropathy. All current guidelines advise a personalised approach with a low-dose start that is tailored to the maximum response having the least side effects or adverse events.

New Perspective in Diabetic Neuropathy: From the Periphery to the Brain, a Call for Early Detection, and Precision Medicine

Diabetic peripheral neuropathy (DPN) is a common chronic complication of diabetes mellitus. It leads to distressing and expensive clinical sequelae such as foot ulceration, leg amputation, and neuropathic pain (painful-DPN). Unfortunately, DPN is often diagnosed late when irreversible nerve injury has occurred and its first presentation may be with a diabetic foot ulcer. Several novel diagnostic techniques are available which may supplement clinical assessment and aid the early detection of DPN. Moreover, treatments for DPN and painful-DPN are limited. Only tight glucose control in type 1 diabetes has robust evidence in reducing the risk of developing DPN. However, neither glucose control nor pathogenetic treatments are effective in painful-DPN and symptomatic treatments are often inadequate. It has recently been hypothesized that using various patient characteristics it may be possible to stratify individuals and assign them targeted therapies to produce better pain relief. We review the diagnostic techniques which may aid the early detection of DPN in the clinical and research environment, and recent advances in precision medicine techniques for the treatment of painful-DPN.

Metformin and Micronutrient Status in Type 2 Diabetes: Does Polypharmacy Involving Acid-Suppressing Medications Affect Vitamin B12 Levels?

Metformin is the first-choice drug in uncomplicated type 2 diabetes (T2DM) and is effective in improving glycaemic control. It is the most widely prescribed oral antidiabetic medicine and has a good safety profile. However, there is an abundance of evidence that metformin use is associated with decreased Vitamin B12 status, though the clinical implications of this in terms of increased risk of diabetic peripheral neuropathy are debated. There is growing evidence that other B vitamins, vitamin D and magnesium may also be impacted by metformin use in addition to alterations to the composition of the microbiome, depending on the dose and duration of therapy. Patients using metformin for prolonged periods may, therefore, need initial screening with intermittent follow-up, particularly since vitamin B₁₂ deficiency has similar symptoms to diabetic neuropathy which itself affects 40-50% of patients with T2DM at some stage. Among patients with T2DM, 40% are reported to experience symptomatic gastroesophageal reflux disease (GORD), of whom 70% use oral antidiabetic medications. The most common medications used to treat GORD are proton pump inhibitors (PPIs) and antagonists of histamine selective H₂ receptors (H₂RAs), both of which independently affect vitamin B₁₂ and magnesium status. Research indicates that co-prescribing metformin with either PPIs or H₂RAs can have further deleterious effects on vitamin B₁₂ status. Vitamin B12 deficiency related to metformin and polypharmacy is likely to contribute to the symptoms of diabetic neuropathy which may frequently be under-recognised. This review explores current knowledge surrounding these issues and suggests treatment strategies such as supplementation.

The Role of Physical Therapists in Fighting the Type 2 Diabetes Epidemic

BACKGROUND

In 2014, the total prevalence of diabetes was estimated to be 422 million people worldwide. Due to the aging population and continued increase in obesity rates, the prevalence is expected to rise to 592 million by 2035. Diabetes can lead to several complications, including cardiovascular disease, stroke, peripheral arterial disease, nephropathy, neuropathy, retinopathy, lower extremity amputation, and musculoskeletal impairments.

CLINICAL QUESTION

Up to 80% of patients referred for outpatient physical therapy have diabetes or are at risk for diabetes, providing an opportunity for physical therapists to intervene. Therefore, we asked, "What is the role of physical therapists in fighting the diabetes epidemic?"

KEY RESULTS

Physical therapists commonly prescribe physical activity for the treatment of diabetes and other chronic diseases, such as cardiovascular disease and osteoarthritis. Physical therapists may also screen for risk factors for diabetes and diabetes-related complications and modify traditional musculoskeletal exercise prescription accordingly. Physical therapists must advocate for regular physical activity as a key component of the treatment of chronic diseases in all patient interactions.

CLINICAL APPLICATION

This commentary (1) describes the diabetes epidemic and the health impact of diabetes and diabetes-related complications, (2) highlights the physical therapist's role as front-line provider, and (3) provides recommendations for physical therapists in screening for diabetes risk factors and diabetes-related complications and considerations for patient management. We focus on type 2 diabetes. J Orthop Sports Phys Ther 2020;50(1):5-16. Epub 28 Nov 2019. doi:10.2519/jospt.2020.9154.

Whole body vibration showed beneficial effect on pain, balance measures and quality of life in painful diabetic peripheral neuropathy: a randomized controlled trial

Purpose

The aim of the study was to determine the efficacy of whole body vibration (WBV) therapy on pain, neuropathy disability score, balance, proprioception and quality of life (QOL) in patients with painful diabetic peripheral neuropathy (PDPN).

Methods

Twenty-six (16 males and 10 females) patients with PDPN were selected on the basis of inclusion and exclusion criteria. Subjects were randomly allocated to an experimental group (n = 13, age = 60.69 ± 5.08) and a control group (n = 13, age = 59.54 ± 4.25). The experimental group was given WBV therapy for six weeks (3 days/week) in addition to standard medical care, dietary advice and lifestyle modifications. Control group was provided only standard medical care, dietary advice and lifestyle modifications. Outcome measures included numeric pain rating scale (NPRS), Leeds assessment of neuropathic symptoms and signs (LANSS), vibration perception threshold (VPT), neuropathy disability score (NDS), proprioception, single-leg stance test (SLST), timed up and go test (TUGT) and short form 36 questionnaire (SF-36).

Results

NPRS, LANSS, NDS, SLST and TUGT showed significant time effect (p ≤ 0.022) and time×group interaction (p ≤ 0.007), whereas group effect was found to be significant only in LANSS (p = 0.001). VPT showed significant group effect (p ≤ 0.045) and time×group interaction (p ≤ 0.007) at great toe, metatarsal head and total average score. SF-36 was found to be significant time effect (p ≤ 0.024) in all domains except limitations due to physical health (p = 0.461). SF-36 average score was found be significant for group effect (p = 0.002) and time×group interaction (p < 0.001).

Conclusion

WBV improves sensory sensations like pain and vibration perception, neuropathy disability score, balance measures and health-related QOL in PDPN.

Associations of serum low-density lipoprotein and systolic blood pressure levels with type 2 diabetic patients with and without peripheral neuropathy: systemic review, meta-analysis and meta-regression analysis of observational studies

BACKGROUND

Compositional abnormalities in lipoproteins and cardiovascular risk factors play an important role in the progression of diabetic peripheral neuropathy (DPN). This systematic review aimed to estimate the predicting value of low-density lipoprotein (LDL) and systolic blood pressure (SBP) level in type-2 diabetes mellitus (T2DM) patients with and without peripheral neuropathy. We also tried to determine whether LDL and SBP are associated with an increased collision risk of DPN.

METHODS

A systematic search was conducted for eligible publications which explored the LDL and SBP level in T2DM patients with and without peripheral neuropathy. The quality of the included studies was assessed by the QUADAS-2 tool. The standardized mean difference (SMD) with 95% CI of LDL and SBP level were pooled to assess the correlation between LDL and SBP level with DPN. We performed random effects meta-regression analyses to investigate factors associated with an increased collision risk of DPN.

RESULTS

There was a significant association between LDL and SBP with poor prognosis of DPN in those included studies (I₂ = 88.1% and I₂ = 84.9%, respectively, Both P < 0.001). European T2DM patients have higher serum level of LDL in compare with the European DPN patients (SMD = 0.16, 95% CI: - 0.06 - 0.38; P < 0.001). SBP level was associated with a 2.6-fold decrease in non-DPN patients of T2DM (SMD = - 2.63, 95% CI: - 4.00 - -1.27, P < 0.001). Old age European T2DM patients have significantly high risk for diabetes drivers. Furthermore, the results of the case-control study design model are more precise to show the accuracy of SBP in Asian T2DM patients.

CONCLUSION

Our finding supports the LDL and SBP status could be associated with increased risk of peripheral neuropathy in T2DM patients.

Hor CP, Fung WY, Ang HA, Lim SC, Kam LY, Sim SW, Lim LH, Choon WY, Wong JW, Ch'ng ASH, Beh KKM, Wee HC, Ong LM, Khan NAK, Sulaiman SAS, Shuaib IL, Bakar A, Yusof Y, Yusof YM, Abu Bakar F, Tang WS, Teh HL, Wahid NA, Saaidin S, Idris N, Yoon CK, Ong HN, Ganapathy JT, Loo CE, Samy MM, Zainal H, Dharan SCS, Ooi BY, Teoh PY, Tye YL, Yeoh CA, Low DW, Looi I, Yuen KH. Efficacy of Oral Mixed Tocotrienols in Diabetic Peripheral Neuropathy: A Randomized Clinical Trial

Importance

Management of painful diabetic peripheral neuropathy remains challenging. Most therapies provide symptomatic relief with varying degrees of efficacy. Tocotrienols have modulatory effects on the neuropathy pathway and may reduce neuropathic symptoms with their antioxidative and anti-inflammatory activities.

Objective

To evaluate the efficacy of oral mixed tocotrienols for patients with diabetic peripheral neuropathy.

Design, Setting, and Participants

The Vitamin E in Neuroprotection Study (VENUS) was a parallel, double-blind, placebo-controlled trial that recruited participants from January 30, 2011, to December 7, 2014, with 12 months of follow-up. This trial screened 14 289 patients with diabetes from 6 health clinics and ambulatory care units from 5 public hospitals in Malaysia. A total of 391 patients who reported neuropathic symptoms were further assessed with Total Symptom Score (TSS) and Neuropathy Impairment Score (NIS). Patients 20 years or older with a TSS of 3 or higher and an NIS of 2 or higher were recruited.

Interventions

Patients were randomized to receive 200 mg of mixed tocotrienols twice daily or matching placebo for 12 months. Patients with hyperhomocysteinemia (homocysteine level ≥2.03 mg/L) received oral folic acid, 5 mg once daily, and methylcobalamin, 500 μg thrice daily, in both groups.

Main Outcomes and Measures

The primary outcome was patient-reported neuropathy TSS (lancinating pain, burning pain, paresthesia, and asleep numbness) changes at 12 months. The secondary outcomes were NIS and sensory nerve conduction test result.

Results

Of 391 eligible patients, 300 were recruited (130 [43.3%] male; mean [SD] age, 57.6 [8.9] years; mean [SD] duration of diabetes, 11.4 [7.8] years) and 229 (76.3%) completed the trial. The TSS changes between the tocotrienols and placebo groups at 12 months (-0.30; 95% CI, -1.16 to 0.56; P = .49) were similar. No significant differences in NIS (0.60; 95% CI, -1.37 to 2.65; P = .53) and sensory nerve conduction test assessments were found between both groups. In post hoc subgroup analyses, tocotrienols reduced lancinating pain among patients with hemoglobin A1C levels greater than 8% (P = .03) and normohomocysteinemia (homocysteine level <2.03 mg/L; P = .008) at 1 year. Serious adverse events in both groups were similar, except more infections were observed in the tocotrienols group (6.7% vs 0.7%, P = .04). Results reported were of modified intention-to-treat analyses.

Conclusions and Relevance

Supplementation of oral mixed tocotrienols, 400 mg/d for 1 year, did not improve overall neuropathic symptoms. The preliminary observations on lancinating pain among subsets of patients require further exploration.

Trial Registration

National Medical Research Registry Identifier: NMRR-10-948-7327 and clinicaltrials.gov Identifier: NCT01973400.

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.

Ameliorative Effect of Berberine on Neonatally Induced Type 2 Diabetic Neuropathy via Modulation of BDNF, IGF-1, PPAR-γ, and AMPK Expressions

Neonatal-streptozotocin (n-STZ)-induced diabetes mimics most of the clinicopathological symptoms of type 2 diabetes mellitus (T2DM) peripheral neuropathy. Berberine, a plant alkaloid, is reported to have antidiabetic, antioxidant, anti-inflammatory, and neuroprotective potential. The aim of the present study was to investigate the potential of berberine against n-STZ-induced painful diabetic peripheral polyneuropathy by assessing various biochemical, electrophysiological, morphological, and ultrastructural studies. Type 2 diabetes mellitus was produced neonatal at the age of 2 days (10-12 g) by STZ (90 mg/kg intraperitoneal). After confirmation of neuropathy at 6 weeks, rats were treated with berberine (10, 20, and 40 mg/kg). Administration of n-STZ resulted in T2DM-induced neuropathic pain reflected by a significant alterations (P < .05) in hyperalgesia, allodynia, and motor as well as sensory nerve conduction velocities whereas berberine (20 and 40 mg/kg) treatment significantly attenuated (P < .05) these alterations. Berberine treatment significantly inhibited (P < .05) STZ-induced alterations in aldose reductase, glycated hemoglobin, serum insulin, hepatic cholesterol, and triglyceride levels. The elevated oxido-nitrosative stress and decreased Na-K-ATPase and pulse Ox levels were significantly attenuated (P < .05) by berberine. It also significantly downregulated (P < .05) neural tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 messenger RNA (mRNA), and protein expressions both. Streptozotocin-induced downregulated mRNA expressions of brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1), and peroxisome proliferator-activated receptors-γ (PPAR-γ) in sciatic nerve were significantly upregulated (P < .05) by berberine. Western blot analysis revealed that STZ-induced alterations in adenosine monophosphate protein kinase (AMPK; Thr-172) and protein phosphatase 2C-α protein expressions in dorsal root ganglia were inhibited by berberine. It also attenuated histological and ultrastructural alterations induced in sciatic nerve by STZ. In conclusion, berberine exerts its neuroprotective effect against n-STZ-induced diabetic peripheral neuropathy via modulation of pro-inflammatory cytokines (TNF α, IL-1β, and IL-6), oxido-nitrosative stress, BDNF, IGF-1, PPAR-γ, and AMPK expression to ameliorate impaired allodynia, hyperalgesia, and nerve conduction velocity during T2DM.

Painful diabetic peripheral neuropathy: Health care costs and complications from 2010 to 2015

Objective

To quantify health care resource utilization and risk of complications in painful diabetic peripheral neuropathy (pDPN).

Methods

Adult patients diagnosed with diabetes mellitus or diabetic peripheral neuropathy (DPN) were identified in MarketScan from January 2010 to December 2015. Subgroups (pDPN and nonpainful DPN) were based on the use of pain medications 6 months before a new indexed diagnosis and 1 year thereafter. Health care costs were collected for up to 5 years, and complications charted for those with at least 1 and 2 years of follow-up. Complication comparisons were made using χ² or Fisher exact tests, and a multivariable regression cost model was fit with log link function using generalized estimating equations.

Results

Among 360,559 patients with diabetes (62 ± 14 years; 54.3% female), 84,069 (23.3%) developed pDPN, 17,267 (4.8%) experienced nonpainful DPN, and the majority (259,223, 71.9%) were controls with diabetes without neuropathy. At baseline, costs associated with pDPN patients were 20% higher than diabetic controls (95% confidence interval [CI] [1.19, 1.21], p < 0.001), which increased to 31% in the 5th year (95% CI [1.27, 1.34], p < 0.001). Patients with pDPN had 200%, 356%, and 224% of the odds of using opioids, anticonvulsants, and antidepressants, respectively, compared with diabetic controls. The amputation risk in the pDPN subgroup was 16.24 times that of diabetic controls (95% CI [2.15, 122.72], p = 0.0003), and 87% more patients with pDPN experienced lower extremity infections (95% CI [1.43, 2.46], p < 0.0001) within a year. Within 2 years, 2.2% of patients with pDPN had falls and fall-related injuries compared with 1.1% of diabetic controls (p < 0.0001).

Conclusions

Our study characterizes a substantial pDPN cohort in the United States, demonstrating considerable morbidity and economic costs.

Painful and Painless Diabetic Neuropathies: What Is the Difference?

PURPOSE OF REVIEW

The prevalence of diabetes mellitus and its chronic complications are increasing to epidemic proportions. This will unfortunately result in massive increases in diabetic distal symmetrical polyneuropathy (DPN) and its troublesome sequelae, including disabling neuropathic pain (painful-DPN), which affects around 25% of patients with diabetes. Why these patients develop neuropathic pain, while others with a similar degree of neuropathy do not, is not clearly understood. This review will look at recent advances that may shed some light on the differences between painful and painless-DPN.

RECENT FINDINGS

Gender, clinical pain phenotyping, serum biomarkers, brain imaging, genetics, and skin biopsy findings have been reported to differentiate painful- from painless-DPN. Painful-DPN seems to be associated with female gender and small fiber dysfunction. Moreover, recent brain imaging studies have found neuropathic pain signatures within the central nervous system; however, whether this is the cause or effect of the pain is yet to be determined. Further research is urgently required to develop our understanding of the pathogenesis of pain in DPN in order to develop new and effective mechanistic treatments for painful-DPN.

Insights for Care: The Healthcare Utilisation and Cost Impact of Managing Type 2 Diabetes-Associated Microvascular Complications

INTRODUCTION

The increasing prevalence of type 2 diabetes (T2DM) in the UK imposes a significant burden on the National Health Service (NHS). Despite the availability of effective treatments, the loss of glycaemic control over time results in significant comorbidities, including nephropathy, neuropathy and retinopathy. The cost of treating these microvascular complications has not been well documented, and this study aimed to provide an accurate assessment of the healthcare resource utilisation (HCRU) associated with managing T2DM and its complications.

METHODS

This retrospective cohort study utilised electronic medical records from patients with T2DM from the Heart of England Foundation Trust (HEFT), which captures data from patients using secondary care services. Patients were diagnosed with microvascular complications based on ICD-10 or OPCS codes. HCRU over a 2-year period was based on NHS Tariffs for healthcare services for inpatient, accident and emergency, and dialysis clinic usage.

RESULTS

The study cohort comprised 26,629 patients with T2DM who used HEFT services during the study period, 22.6%, 20.8% and 3.1% of whom had comorbid nephropathy, retinopathy or neuropathy, respectively. While the prevalence of diabetes in the overall HEFT population was reported to be 7% in 2012, diabetes and its associated complications accounted for more than 30% of secondary care costs. Furthermore, while patients with diabetes represent only 17% of HEFT inpatients, they account for more than 20% of service usage. The economic burden of microvascular complications increased substantially with the severity of the condition, with the overall cost exceeding £70 million over the 2-year period.

CONCLUSION

This study of patients with T2DM in a typical secondary care provider in the UK showed that avoiding the progression of microvascular complications could provide substantial cost savings through targeted interventions that improve outcomes and lower resource use.

FUNDING

Merck Sharp & Dohme Limited.

A Cost-Effectiveness Model for Adjunctive Smoked Cannabis in the Treatment of Chronic Neuropathic Pain

Background: A recent meta-analysis affirmed the benefit of medicinal cannabis for chronic neuropathic pain, a disabling and difficult-to-treat condition. As medicinal cannabis use is becoming increasingly prevalent among Americans, an exploration of its economic feasibility is warranted. We present this cost-effectiveness analysis of adjunctive cannabis pharmacotherapy for chronic peripheral neuropathy.

Materials and Methods: A published Markov model comparing conventional therapies for painful diabetic neuropathy was modified to include arms for augmenting first-line, second-line (if first-line failed), or third-line (if first- and second-line failed) therapies with smoked cannabis. Microsimulation of 1,000,000 patients compared the cost (2017 U.S. dollars) and effectiveness (quality-adjusted life years [QALYs]) of usual care with and without adjunctive cannabis using a composite of third-party and out-of-pocket costs. Model efficacy inputs for cannabis were adapted from clinical trial data. Adverse event rates were derived from a prospective study of cannabis for chronic noncancer pain and applied to probability inputs for conventional therapies. Cannabis cost was derived from retail market pricing. Parameter uncertainty was addressed with one-way and probabilistic sensitivity analysis.

Results: Adding cannabis to first-line therapy was incrementally less effective and costlier than adding cannabis to second-line and third-line therapies. Third-line adjunctive cannabis was subject to extended dominance, that is, the second-line strategy was more effective with a more favorable incremental cost-effectiveness ratio of $48,594 per QALY gained, and therefore, third-line adjunctive cannabis was not as cost-effective. At a modest willingness-to-pay threshold of $100,000/QALY gained, second-line adjunctive cannabis was the strategy most likely to be cost-effective.

Conclusion: As recently proposed willingness-to-pay thresholds for the United States health marketplace range from $110,000 to $300,000 per QALY, cannabis appears cost-effective when augmenting second-line treatment for painful neuropathy. Further research is warranted to explore the long-term benefit of smoked cannabis and standardization of its dosing for chronic neuropathic pain.

AAPT Diagnostic Criteria for Peripheral Neuropathic Pain: Focal and Segmental Disorders

Peripheral neuropathic pain is among the most prevalent types of neuropathic pain. No comprehensive peripheral neuropathic pain classification system that incorporates contemporary clinical, diagnostic, biological, and psychological information exists. To address this need, this article covers the taxonomy for 4 focal or segmental peripheral neuropathic pain disorders, as part of the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership and the American Pain Society (APS) collaborative to develop a standardized, evidence-based taxonomy initiative: the ACTTION-APS Pain Taxonomy (AAPT). The disorders-postherpetic neuralgia, persistent posttraumatic neuropathic pain, complex regional pain disorder, and trigeminal neuralgia-were selected because of their clinical and clinical research relevance. The multidimensional features of the taxonomy are suitable for clinical trials and can also facilitate hypothesis-driven case-control and cohort epidemiologic studies. PERSPECTIVE: The AAPT peripheral neuropathic pain taxonomy subdivides the peripheral neuropathic pain disorders into those that are generalized and symmetric and those that are focal or segmental and asymmetric. In this article, we cover the focal and segmental disorders: postherpetic neuralgia, persistent posttraumatic neuropathic pain, complex regional pain disorder, and trigeminal neuralgia. The taxonomy is evidence-based and multidimensional, with the following dimensions: 1) core diagnostic criteria; 2) common features; 3) common medical and psychiatric comorbidities; 4) neurobiological, psychosocial, and functional consequences; and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors.

Altered pain processing in people with type I and II diabetes: a protocol for a systematic review and meta-analysis of pain threshold and pain modulation mechanisms

BACKGROUND

Peripheral neuropathies are a common complication in patients with diabetes. Changes in nerve function and central pain processing can be quantified by assessing pain thresholds and pain modulation mechanisms.

AIM

To summarise the literature which compares pain thresholds and pain modulation mechanisms in people with diabetes without neuropathies, with non-painful diabetic neuropathies and with painful diabetic neuropathies, and in people without diabetes.

METHODS

A systematic review and meta-analysis will be conducted. Terms related to diabetes, pain thresholds and pain modulation mechanisms will be combined in a structured search in MEDLINE, CINAHL, EMBASE, the Cochrane Library, SPORTDiscus, Web of Science and PEDro. Publications on adults (18 years and older) with diabetes and at least one pain threshold measure following thermal, mechanical or electrical stimuli and/or at least one pain modulation mechanisms (temporal summation or conditioned pain modulation) with a comparison group will be considered. There will be no restriction regarding language or year of publication. One investigator will screen records based on title and abstract (ESS). Two independent investigators (ESS and MC) will select full-text papers and assess risk of bias using a modified Downs and Black checklist. Potential disagreements will be resolved with a third investigator (LB). One investigator (ESS) will extract all data and a second investigator (MS) will extract data for 20% of the papers to verify accuracy of the process. A sensitivity analysis for publication bias will be conducted.

DISCUSSION

This systematic review and meta-analysis will summarise the evidence on pain threshold profiles and pain modulation mechanisms in people with diabetes without and with neuropathies (both painful and non-painful). This will provide more insight in the clinical presentation and progression of diabetic neuropathies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018088173.

Phenotypic Characterization of Paclitaxel-Induced Peripheral Neuropathy in Cancer Survivors

CONTEXT

Although paclitaxel is one of the most commonly used drugs to treat breast, ovarian, and lung cancers, little is known about the impact of paclitaxel-induced peripheral neuropathy (PIPN) on cancer survivors.

OBJECTIVES

The purposes of this study were to evaluate for differences in demographic and clinical characteristics as well as measures of sensation, balance, upper extremity function, perceived stress, symptom burden, and quality of life (QOL) between survivors who received paclitaxel and did (n = 153) and did not (n = 58) develop PIPN.

METHODS

Pain characteristics associated with PIPN are described in detail. Both subjective and objective measures were used to evaluate the impact of PIPN.

RESULTS

Survivors with PIPN were significantly older, had a higher body mass index, and a worse comorbidity profile. The duration of PIPN was almost four years, and pain scores were in the moderate range. Compared with survivors without PIPN, survivors with PIPN had a higher number of upper and lower extremity sites that had lost light touch, cold, and pain sensations. Survivors with PIPN had worse upper extremity function, more problems with balance, a higher symptom burden, and higher levels of perceived stress. In addition, survivors with PIPN had worse QOL scores particularly in the domain of physical functioning.

CONCLUSION

The findings from this large descriptive study are the first to document the impact of PIPN on survivors' symptom burden, functional status, and QOL.

A new look at painful diabetic neuropathy

The prevalence of diabetes mellitus and its chronic complications continue to increase alarmingly. Consequently, the massive expenditure on diabetic distal symmetrical polyneuropathy (DSPN) and its sequelae, will also likely rise. Up to 50% of patients with diabetes develop DSPN, and about 20% develop neuropathic pain (painful-DSPN). Painful-DSPN can cast a huge burden on sufferers' lives with increased rates of unemployment, mental health disorders and physical co-morbidities. Unfortunately, due to limited understanding of the mechanisms leading to painful-DSPN, current treatments remain inadequate. Recent studies examining the pathophysiology of painful-DSPN have identified maladaptive alterations at the level of both the peripheral and central nervous systems. Additionally, genetic studies have suggested that patients with variants of voltage gated sodium channels may be more at risk of developing neuropathic pain in the presence of a disease trigger such as diabetes. We review the recent advances in genetics, skin biopsy immunohistochemistry and neuro-imaging, which have the potential to further our understanding of the condition, and identify targets for new mechanism based therapies.

Zusanli (ST36) Acupoint Injection for Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Controlled Trials

Background: Acupuncture point (acupoint) injection is a common practice in China. Some trials showed that Chinese herbal extracts and/or conventional medication are injected at the Zusanli (ST36) acupoint for the treatment of diabetic peripheral neuropathy (DPN). The study aimed to assess the effectiveness and safety of acupoint injection for DPN at the ST36 by systematically evaluating the evidence published to date. Methods: Six databases were searched for randomized controlled trials (RCTs) of ST36 injection for DPN with primary outcome of pain, global symptom improvement, and quality of life. Methodological quality was assessed by the Cochrane risk of bias (ROB) tool. Data were analyzed using RevMan 5.3. Results: Fourteen RCTs involving 1,071 participants with DPN were included. All RCTs were assessed as unclear or high ROB. Few RCTs adequately reported methodology-related items and needling details according to Consolidated Standards of Reporting Trials (CONSORT) and Standards for Reporting Interventions in Controlled Trials of Acupuncture (STRICTA) statement. Medications injected at ST36 included conventional medications (11 RCTs) and Chinese herbal extracts (3 RCTs). The authors of this study did not perform any meta-analysis due to the heterogeneity of medications used for injections. Two individual RCTs favored ST36 injection in relieving pain compared with intramuscular injection of the same medication. For global symptom measured by Toronto clinical scoring system, one RCT showed that ST36 injection of Fufang Danggui was more effective than intramuscular injection of vitamin B₁₂, two RCTs demonstrated that ST36 injection of mecobalamin or Danhong with cointervention was superior, while one RCT showed no significant differences between ST36 injection and intramuscular injection of mecobalamin. For improving nerve conduction velocity (NCV), three of four individual RCTs showed that ST36 injection was better than intramuscular or intravenous injection of the same medication, two RCTs favored ST36 injection with cointervention, and one RCT favored ST36 injection without cointervention. Four RCTs reported monitoring adverse events, all of which showed no significant difference between groups. Conclusions: Limited evidence suggests that ST36 injection appears to be safe, and potentially effective in reducing pain score and improving NCV compared with intramuscular injection of the same medication. However, poor methodological and reporting quality reduced confidence in the findings. Rigorously designed and well-reported RCTs evaluating the effectiveness of ST36 injection for DPN are warranted.

Glial-derived neurotrophic factor is essential for blood-nerve barrier functional recovery in an experimental murine model of traumatic peripheral neuropathy

There is emerging evidence that glial-derived neurotrophic factor (GDNF) is a potent inducer of restrictive barrier function in tight junction-forming microvascular endothelium and epithelium, including the human blood-nerve barrier (BNB) in vitro. We sought to determine the role of GDNF in restoring BNB function in vivo by evaluating sciatic nerve horseradish peroxidase (HRP) permeability in tamoxifen-inducible GDNF conditional knockout (CKO) adult mice following non-transecting crush injury via electron microscopy, with appropriate wildtype (WT) and heterozygous (HET) littermate controls. A total of 24 age-, genotype- and sex-matched mice >12 weeks of age were injected with 30 mg/kg HRP via tail vein injection 7 or 14 days following unilateral sciatic nerve crush, and both sciatic nerves were harvested 30 minutes later for morphometric assessment by light and electron microscopy. The number and percentage of HRP-permeable endoneurial microvessels were ascertained to determine the effect of GDNF in restoring barrier function in vivo. Following sciatic nerve crush, there was significant upregulation in GDNF protein expression in WT and HET mice that was abrogated in CKO mice. GDNF significantly restored sciatic nerve BNB HRP impermeability to near normal levels by day 7, with complete restoration seen by day 14 in WT and HET mice. A significant recovery lag was observed in CKO mice. This effect was independent on VE-Cadherin or claudin-5 expression on endoneurial microvessels. These results imply an important role of GDNF in restoring restrictive BNB function in vivo, suggesting a potential strategy to re-establish the restrictive endoneurial microenvironment following traumatic peripheral neuropathies.

An Assessment of Clinically Important Differences on the Worst Pain Severity Item of the Modified Brief Pain Inventory in Patients with Diabetic Peripheral Neuropathic Pain

Objectives

Using patient global impression of change (PGIC) as an anchor, an approximately 30% reduction on an 11-point numeric pain intensity rating scale (PI-NRS) is considered a clinically important difference (CID) in pain. Our objective was to define the CID for another pain measure, the worst pain severity (WPS) item of the modified Brief Pain Inventory (m-BPI).

Methods

In this post hoc analysis of a double-blind, placebo-controlled, phase 2 study, 452 randomized patients with diabetic peripheral neuropathic pain (DPNP) were followed over 5 weeks, with m-BPI data collected weekly and PGIC at treatment conclusion. Receiver operating characteristic (ROC) curves (via logistic regression) were used to determine the changes in the m-BPI-WPS score that best predicted ordinal clinical improvement thresholds (i.e., "minimally improved" or better) on the PGIC.

Results

Similar to the PI-NRS, a change of -3 (raw) or -33.3% from the baseline on the m-BPI-WPS optimized prediction for the "much improved" or better PGIC threshold and represents a CID. There was a high correspondence between observed and predicted PGIC categories at each PGIC threshold (ROC AUCs were 0.78-0.82).

Conclusions

Worst pain on the m-BPI may be used to assess clinically important improvements in DPNP studies. Findings require validation in larger studies.

Text Messaging to Improve Disease Management in Patients With Painful Diabetic Peripheral Neuropathy

Purpose The purpose of the study was to determine the impact of educational text messages on diabetes self-management activities and outcomes in patients with painful diabetic peripheral neuropathy (pDPN). Methods Patients with pDPN identified from a large integrated health system who agreed to participate were randomized to 6 months of usual care (UC) or UC plus twice-daily diabetes self-management text messages (UC+TxtM). Outcomes included the Pain Numerical Rating Scale, Summary of Diabetes Self-Care Activities (SDSCA), questions on diabetes health beliefs, and glycated hemoglobin (A1C). Changes from baseline were evaluated at 6 months and compared between groups. Results Demographic characteristics were balanced between groups (N = 62; 53% female, mean age = 63 years, 94% type 2 diabetes), as were baseline measures. After 6 months, pain decreased with UC+TxtM from 6.3 to 5.5 and with UC from 6.5 to 6.0, with no difference between groups. UC+TxtM but not UC was associated with significant improvements from baseline on all SDSCA subscales. On diabetes health beliefs, UC+TxtM patients reported significantly increased benefits and reduced barriers and susceptibility relative to UC at 6 months. A1C declined in both groups, but neither change was significant relative to baseline. Conclusions Patients with pDPN who receive twice-daily text messages regarding diabetes management reported reduced pain relative to baseline, although this change was not significant compared with usual care. In addition, text messaging was associated with increased self-management activities and improved diabetes health beliefs and total self-care. These results warrant further investigation.

Association between a MIR499A polymorphism and diabetic neuropathy in type 2 diabetes

AIMS

Diabetic polyneuropathy (DPN) and cardiovascular autonomic neuropathy (CAN) affect a large percentage of diabetic people and impact severely on quality of life. As it seems that miRNAs and their variations might play a role in these complications, we investigated whether the rs3746444 SNP in the MIR499A gene could be associated with susceptibility to DPN and/or CAN.

METHODS

We analyzed 150 participants with type 2 diabetes. DNA was extracted from peripheral blood samples and genotyping was performed by TaqMan genotyping assay. Cardiovascular tests, MNSI-Q and MDNS for neuropathic symptoms and signs, VPT, and thermal thresholds were used for CAN and DPN assessment. We performed a genotype-phenotype correlation analysis.

RESULTS

We observed that the GG genotype was associated with a higher risk of developing CAN (P=0.002 and OR=16.08, P=0.0005 and OR=35.02, for early and confirmed CAN, respectively) and DPN (P=0.037 and OR=6.56), after correction for BMI, sex, age, HbA1c and disease duration. Moreover, the GG genotype was associated with worse values of MDNS (P=0.017), VPT (P=0.01), thermal thresholds (P=0.01), and CAN score (P<0.001). A logistic multivariate analysis confirmed that MIR499A GG genotype, disease duration and HbA1c contributed to early CAN (R²=0.26), while the same variables and age contributed to DPN (R²=0.21). With a multiple linear regression, we observed that GG genotype (P=0.001) and disease duration (P=0.035) were the main variables contributing to the CAN score (R²=0.35).

CONCLUSIONS

We described for the first time that the MIR499A genetic variation could be involved in diabetic neuropathies susceptibility. In particular, patients carrying the rs3746444 GG genotype had a higher risk of CAN development, together with a more severe form of CAN.

Perspectives on the impact of painful diabetic peripheral neuropathy in a multicultural population

Background

Since few studies have characterized painful diabetic peripheral neuropathy (pDPN) symptoms in multicultural populations, this study fielded a survey to better understand pDPN and its impact in African-American, Caucasian, and Hispanic populations.

Methods

Kelton fielded a survey by phone or Internet, in English or Spanish, among adults with pDPN symptoms in the United States between August and October 2015; African-Americans and Hispanics were oversampled to achieve at least 500 subjects for each group. Patients were required to have been diagnosed with pDPN or score ≥ 3 on ID Pain validated screening tool. The survey elicited information on pDPN symptoms and interactions with healthcare providers (HCPs), and included the Brief Pain Inventory and pain-specific Work Productivity and Assessment Questionnaire (WPAI:SHP).

Results

Respondents included 823 Caucasians, 525 African-Americans, and 537 Hispanics; approximately half of African-Americans and Hispanics were <40 years of age, vs 12% of Caucasians. Pain was less likely to be rated moderate or severe by African-Americans (65%) and Hispanics (49%) relative to Caucasians (87%; p < 0.05). African-Americans and Hispanics were less likely than Caucasians to report experiencing specific pDPN sensory symptoms. Significantly fewer African-Americans and Hispanics reported receiving a pDPN diagnosis relative to Caucasians (p < 0.05), and higher proportions of African-Americans and Hispanics reported difficulty communicating with their HCP (p < 0.05). WPAI:SHP activity impairment was lower in Hispanics (43%) relative to African-Americans (53%) and Caucasian (56%; p < 0.05).

Conclusions

Multicultural patients reported differences in pDPN symptoms and pain relative to Caucasians, and fewer received a pDPN diagnosis. While further evaluation is needed to understand these differences, these data suggest a need to broaden pDPN educational initiatives to improve patient-HCP dialogue and encourage discussion of pDPN symptoms and their impact in a multicultural setting.

Electronic supplementary material

The online version of this article (10.1186/s40842-017-0051-2) contains supplementary material, which is available to authorized users.

Using Random Forest Models to Identify Correlates of a Diabetic Peripheral Neuropathy Diagnosis from Electronic Health Record Data

Objective

To identify variables correlated with a diagnosis of diabetic peripheral neuropathy (DPN) using random forest modeling applied to electronic health records.

Design

Retrospective analysis.

Setting

Humedica de-identified electronic health records database.

Subjects

Subjects ≥ 18 years old with type 2 diabetes from January 1, 2008-September 30, 2013 having continuous data for 1 year pre- and postindex with DPN (n = 35,050) and without DPN (n = 288,328) were identified.

Methods

Demographic, clinical, and health care resource utilization variables (e.g., inpatient and outpatient encounters, medications, and procedures) were input into a random forest model to identify the most important correlates of a DPN diagnosis. Random forest modeling is a computationally extensive, robust data mining technique that accommodates large sets of variables to identify associated factors using an ensemble of classifications trees. Accuracy of the model was evaluated using receiver operating characteristic curves (ROC).

Results

The final random forest model consisted of the following variables (importance) associated with a DPN diagnosis: Charlson Comorbidity Index score (100%), age (37.1%), number of pre-index procedures and services (29.7%), number of pre-index outpatient prescriptions (24.2%), number of pre-index outpatient visits (18.3%), number of pre-index laboratory visits (16.9%), number of pre-index outpatient office visits (12.1%), number of inpatient prescriptions (5.9%), and number of pain-related medication prescriptions (4.4%). ROC analysis confirmed model performance, with an area under the curve of 0.824 and accuracy of 89.6% (95% confidence interval 89.4%, 89.8%).

Conclusions

Random forest modeling can determine likelihood of a DPN diagnosis. Further validation of the random forest model may help facilitate earlier diagnosis and enhance management strategies.

Effect of Renal Function on Dosing of Non-Vitamin K Antagonist Direct Oral Anticoagulants Among Patients With Nonvalvular Atrial Fibrillation

BACKGROUND

Non-vitamin K antagonist direct oral anticoagulants (DOACs) are fixed-dose regimens indicated for stroke prevention in nonvalvular atrial fibrillation (NVAF) patients. Dose adjustment is necessary among patients with renal insufficiency to optimize efficacy and safety.

OBJECTIVE

To assess DOAC dosing appropriateness and its effect on clinical outcomes in NVAF patients.

METHODS

Adult NVAF patients with ≥1 DOAC pharmacy claim (January 1, 2013, to December 31, 2014), continuous enrollment for ≥12 months post-index DOAC claim, and documented creatinine clearance within 3 months preindex date in the Optum/Humedica SmartFile database were eligible. DOAC dosage was classified as inappropriate or appropriate by level of renal function, age, and body weight per US prescription information. Cox proportional models were used to assess the risks of bleeding and stroke associated with inappropriate DOAC dosage.

RESULTS

Of the 388 eligible patients, 69 (17.8%) were inappropriately dosed, and rivaroxaban had the highest inappropriate dosing rate. Most inappropriately dosed patients were underdosed. Inappropriately dosed patients were more likely to be older, female, and have a body weight of ≤60 kg; they also had higher mean CHA₂DS₂-VASc and Charlson comorbidity index scores (all P < 0.05). Overtreated patients had a higher risk of bleeding (hazard ratio [HR] = 5.4; P = 0.006) than undertreated patients (HR = 3.1; P = 0.025) relative to appropriately dosed patients. However, no significant difference in stroke risk was observed, most likely because very few stroke events were observed in the study.

CONCLUSIONS

Inappropriate dosing occurred among patients with normal and insufficient renal function. The consideration of clinical factors beyond renal function is necessary to reduce bleeding risk associated with DOAC therapy.

Chemotherapy-Induced Neuropathy in Cancer Survivors

CONTEXT

Evidence suggests that chemotherapy-induced neuropathy (CIN) is a significant problem for cancer survivors. However, a detailed phenotypic characterization of CIN in cancer survivors is not available.

OBJECTIVES

To evaluate between-group differences in demographic and clinical characteristics, as well as in measures of sensation, function, and postural control, in a sample of cancer survivors who received a platinum and/or a taxane-based CTX regimen and did (n = 426) and did not (n = 197) develop CIN.

METHODS

Survivors completed self-report questionnaires and underwent objective testing (i.e., light touch, pain sensation, cold sensation, vibration, muscle strength, grip strength, Purdue Pegboard test, Timed Get Up and Go test, Fullerton Advanced Balance test). Parametric and nonparametric statistics were used to compare between-group differences in study outcomes.

RESULTS

Of the 426 survivors with CIN, 4.9% had CIN only in their upper extremities, 27.0% only in their lower extremities, and 68.1% in both their upper and lower extremities. Demographic and clinical characteristics associated with CIN included the following: older age, lower annual income, higher body mass index, a higher level of comorbidity, being born prematurely, receipt of a higher cumulative dose of chemotherapy, and a poorer functional status. Survivors with CIN had worse outcomes for all of the following objective measures: light touch, pain, temperature, vibration, upper and lower extremity function, and balance.

CONCLUSIONS

This study is the first to provide a detailed phenotypic characterization of CIN in cancer survivors who received a platinum and/or a taxane compound. These data can serve as a benchmark for future studies of CIN in cancer survivors.

Perceptions of Painful Diabetic Peripheral Neuropathy in South-East Asia: Results from Patient and Physician Surveys

There are no data on physician-patient communication in painful diabetic peripheral neuropathy (pDPN) in the Asia-Pacific region. The objective of this study was to examine patient and physician perceptions of pDPN and clinical practice behaviors in five countries in South-East Asia. Primary care physicians and practitioners, endocrinologists, diabetologists, and patients with pDPN completed separate surveys on pDPN diagnosis, impact, management, and physician-patient interactions in Hong Kong, Malaysia, the Philippines, Taiwan, and Thailand. Data were obtained from 100 physicians and 100 patients in each country. The majority of physicians (range across countries, 30-85%) were primary care physicians and practitioners. Patients were mostly aged 18-55 years and had been diagnosed with diabetes for >5 years. Physicians believed pDPN had a greater impact on quality of life than did patients (ranges 83-92% and 39-72%, respectively), but patients believed pDPN had a greater impact on items such as sleep, anxiety, depression, and work than physicians. Physicians considered the diagnosis and treatment of pDPN a low priority, which may be reflected in the generally low incidence of screening (range 12-65%) and a lack of awareness of pDPN. Barriers to treatment included patients' lack of awareness of pDPN. Both physicians and patients agreed that pain scales and local language descriptions were the most useful tools in helping to describe patients' pain. Most patients were monitored upon diagnosis of pDPN (range 55-97%), but patients reported a shorter duration of monitoring compared with physicians. Both physicians and patients agreed that it was patients who initiated conversations on pDPN. Physicians most commonly referred to guidelines from the American Diabetes Association or local guidelines for the management of pDPN. This study highlights important differences between physician and patient perceptions of pDPN, which may impact on its diagnosis and treatment. For a chronic and debilitating complication like pDPN, the physician-patient dialogue is central to maximizing patient outcomes. Strategies, including education of both groups, need to be developed to improve communication.

FUNDING

Pfizer.

Might genetics play a role in understanding and treating diabetic polyneuropathy?

Despite the high prevalence and impact on quality of life, costs, and survival, there are still unresolved issues regarding diabetic polyneuropathy (DPN): the lack of definite knowledge of its pathogenesis; the limited preventive action of glycaemic control in type 2 diabetes; and the unavailability of evidence-based effective disease-modifying treatment. How can genetics provide the tools to address these gaps? Ziegler et al for the GDS Group explore the novel hypothesis that genetic variability in transketolase (TKT) might contribute to susceptibility to DPN in patients with newly diagnosed type 1 and type 2 diabetes (well characterised for DPN). Transketolase diverts excess glycolytic metabolites from the hexosamine, protein kinase C, and advanced glycation endproduct pathways to the pentose phosphate pathway, with a protective effect against hyperglycaemia-induced damage. Moreover, thiamine and its derivative benfotiamine are among the few disease-modifying agents still under consideration as DPN treatment. The authors find significant associations of single-nucleotide polymorphisms of the TKT gene with the Total Symptom Score and thermal thresholds, in particular in male participants with type 2 diabetes. Moreover, they measure plasma methylglyoxal (a glycating agent, whose availability is hindered by TKT) without however finding a relation with TKT single-nucleotide polymorphisms. The link found between TKT genetic variability and nerve function measures is considered here in the context of DPN genetic studies and of experimental and clinical findings regarding thiamine and benfotiamine. The conclusion is that available data supports the decision to maintain focus on both the search for DPN genetic biomarkers and the therapeutic attempts to target thiamine, TKT, and methylglyoxal.

Diabetic peripheral neuropathy may not be as its name suggests: evidence from magnetic resonance imaging

Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include distressing painful neuropathic symptoms and insensitivity to trauma that result in foot ulcerations and amputations. Several recent studies have implicated poor glycemic control, duration of diabetes, hyperlipidemia (particularly hypertryglyceridaemia), elevated albumin excretion rates, and obesity as risk factors for the development of DPN. However, similar data are not available for painful DPN. Moreover, although there is now strong evidence for the importance of peripheral nerve microvascular disease in the pathogenesis of DPN, peripheral structural biomarkers of painful DPN are lacking. However, there is now emerging evidence for the involvement of the central nervous system in both painful and painless DPN afforded by magnetic resonance imaging. This review will focus on this emerging evidence for central changes in DPN, hitherto considered a peripheral nerve disease only.

Alleviation of pain in painful diabetic neuropathy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a disabling pain condition. Its pathomechanism remains unknown, but a sensitization and neuronal hyperexcitabilty have been suggested. Only symptomatic pharmacological pain management treatment is currently available.

AREAS COVERED

The origin of PDN is enigmatic, and the evidence-based therapeutic guidelines therefore consist only of antidepressants and antiepileptics as first-line recommended drugs. This article relates to a MEDLINE/PubMed systematic search (2005-2015).

EXPERT OPINION

The results of the meta-analysis from the aspect of the efficacy of amitriptyline, duloxetine, venlafaxine, gabapentin and pregabalin are favorable, but the placebo response rate is relatively high in patients with neuropathic pain. For personalization of the medication of PDN patients, the optimum dosing, the genotyping of the metabolizing enzymes and optimum biomarkers are needed. As concerns the future perspectives, specific sodium channel subtype inhibitors acting on peripheral nociceptive neurons or modified T-type voltage-gated calcium channel blockers may be promising targets for pharmaceutical innovations. Another attractive strategy for the treatment is based on the effects of monoclonal antibodies against nerve growth factor, sodium channels, specific receptor and cytokines. Botulinum toxin A, capsaicin patch and spinal cord stimulation therapies are the nearest future therapeutic options for the treatment of PDN patients.

Updates in diabetic peripheral neuropathy

Diabetes has become one of the largest global health-care problems of the 21 ^st century. According to the Centers for Disease Control and Prevention, the population prevalence of diabetes in the US is approaching 10% and is increasing by 5% each year. Diabetic neuropathy is the most common complication associated with diabetes mellitus. Diabetes causes a broad spectrum of neuropathic complications, including acute and chronic forms affecting each level of the peripheral nerve, from the root to the distal axon. This review will focus on the most common form, distal symmetric diabetic polyneuropathy. There has been an evolution in our understanding of the pathophysiology and the management of diabetic polyneuropathy over the past decade. We highlight these new perspectives and provide updates from the past decade of research.