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

The efficacy of pregabalin for the treatment of neuropathic pain in Japanese subjects with moderate or severe baseline pain

Purpose

Although analyses of pooled clinical trial data have reported how international populations respond to pregabalin by baseline neuropathic pain (NeP) severity, no studies have evaluated this specifically in patients from Japan. Thus, this post hoc pooled analysis evaluated the efficacy of pregabalin in Japanese subjects for treating moderate or severe baseline NeP.

Patients and methods

Data were pooled from three placebo-controlled trials enrolling Japanese subjects with postherpetic neuralgia (PHN), diabetic peripheral neuropathy (DPN), and spinal cord injury (SCI). The efficacy of pregabalin was evaluated by baseline pain severity (moderate or severe NeP). The trials on PHN and DPN included a 1-week titration of pregabalin from 150 mg/day to 300 or 600 mg/day; the SCI trial included a 4-week dose optimization phase (150 mg/day, titrated up to 600 mg/day). Treatment durations were 13–16 weeks (excluding 1-week taper periods), and pregabalin was administered in two divided doses per day.

Results

Mean baseline pain scores and demographic characteristics were comparable between treatment cohorts. Pregabalin treatment significantly reduced pain scores from baseline to endpoint compared with placebo in subjects with both moderate (P<0.001) and severe (P<0.05) baseline pain. Significant improvements in mean sleep scores from baseline to endpoint were associated with pregabalin compared with placebo in subjects with both moderate and severe baseline pain (both P<0.0001). A greater proportion of subjects in both pain cohorts achieved a ≥30% reduction in pain from baseline with pregabalin vs placebo (P<0.05). Higher proportions of pregabalin-treated vs placebo-treated subjects shifted to a less severe pain category at endpoint. Consistent with the known safety profile of pregabalin, common adverse events included dizziness, somnolence, weight gain, and peripheral edema.

Conclusion

Pregabalin demonstrated efficacy for pain relief and sleep improvement with a consistent safety profile in Japanese subjects with either moderate or severe baseline pain severity.

ClinicalTrials.gov identifiers

NCT0039490130, NCT0055347522, NCT0040774524

Factors of occurrence and improvement methods of presenteeism attributed to diabetes: A systematic review

Objective

A systematic review was performed to study factors of occurrence and improvement methods of presenteeism attributed to diabetes.

Methods

We set 2 clinical questions; (a) how comorbidities and complications of diabetes induce presenteeism and (b) what interventions or conditions effectively improve presenteeism. Then, we conducted a comprehensive search with MEDLINE/PubMed and Scopus databases and extracted those that met the clinical questions.

Results

Eighteen papers studied occurrence of presenteeism by comorbidities and complications of diabetes. Most studies were cross‐sectional and had a low quality of evidence. However, the associations of hypoglycemia, diabetic neuropathy, and mood disorders with presenteeism were relatively well studied. The papers that discussed effective interventions or conditions for improving presenteeism were very limited.

Conclusions

Our review suggests that presenteeism attributed to diabetes is mainly caused by hypoglycemia, diabetic neuropathy, and mood disorders. There are very limited evidences, but available information suggests that improving glycemic control, adjusting treatment regimen by evaluating the impact on work, providing psychological support, and developing suitable work accommodations may effectively reduce presenteeism.

Characteristics of patients with neuropathic pain syndromes screened by the painDETECT questionnaire and diagnosed by physician exam

Background

The aim of this study was to identify the clinical characteristics, treatment usage, and health outcomes of US adults diagnosed with neuropathic pain (NeP) by experienced physicians.

Methods

Adults with scores exceeding the threshold for probable NeP (painDETECT ≥19) and diagnosed with NeP by a qualified physician completed a questionnaire that included comorbid conditions, pain symptoms and experiences, medication use, health status (3-level EuroQol 5 Dimensions (EQ-5D-3L]: health utilities index and visual analog scale), pain severity and interference with functioning (Brief Pain Inventory), and work and activity impairment (Work Productivity and Activity Impairment questionnaire). Descriptive analyses were performed for each NeP subtype.

Results

Participants (n=295) were predominantly female (64.4%), middle-aged (53.9%), and white (51.5%). Chronic low back pain was the most frequently diagnosed major NeP syndrome (n=166), followed by diabetic peripheral neuropathy (n=58), post-trauma neuropathy (n=47), post-surgical neuropathy (n=28), and central NeP (n=23). An additional 45 participants were diagnosed, but did not meet the criteria for the aforementioned subtypes. Participants could be diagnosed with multiple subtypes. Across each NeP subtype, patients reported high rates of comorbid disease, including arthritis (range: 39.1%–64.3%) and high blood pressure (range: 26.1%–69.0%), as well as symptomology that included numbness (range: 68.1%–91.4%) and changes in muscular strength (range: 24.1%–65.2%). The majority of patients reported back pain (range: 77.8%–95.7%) and arthritis/joint pain (range: 68.1%–78.6%). The most commonly reported types of NeP pain medication were non-steroidal anti-inflammatory drugs (range: 43.1%–70.2%), weak opioids (range: 22.2%–39.3%), and strong opioids (range: 8.7%–28.6%). All six NeP groups generally reported similar levels of dysfunction on all self-report measures. The most notable finding was that the EuroQol-5D-3L health utilities index scores for each of the six groups were lower than the US norms by a clinically important amount.

Conclusion

These exploratory findings indicate that patients with NeP across different etiologies are medically complex and experience impaired function across multiple domains.

Epidemiology of physician-diagnosed neuropathic pain in Brazil

OBJECTIVES

Estimate the prevalence of neuropathic pain (NeP) among chronic pain patients attending Brazilian hospitals and pain clinics in São Paulo, Ceara, and Bahia and explore clinical characteristics by subtypes: painful diabetic peripheral neuropathy (pDPN), central neuropathic pain (CNP), chronic low back pain with a neuropathic component (CLBP-NeP), postherpetic neuralgia (PHN), post-traumatic neuropathic pain (PTN), and post-surgical neuropathic pain (PSN).

METHODS

Physicians screened patients reporting chronic pain for ≥3 months (n=2,118) for probable NeP, using the Douleur Neuropathique 4 questionnaire and physician assessment, and reported their NeP subtype(s), symptoms, and medications. Identified NeP patients completed a questionnaire including treatment experiences, quality of life EuroQol 5 Dimensions [EQ-5D]), pain severity and interference (Brief Pain Inventory [BPI]), and Work Productivity and Activity Impairment scales. Descriptive analyses were performed by NeP subtype.

RESULTS

The prevalence of probable NeP was 14.5% (n=307). NeP patients were mostly female (80.5%), middle-aged (mean [M]=52.5, SD=13.9), and Pardo (44.3%). Of those diagnosed with an NeP subtype (n=209), the largest proportions were CLBP-NeP (36.8%), followed by pDPN (18.7%), CNP (17.7%), PTN (17.2%), PSN (13.4%), and PHN (3.3%). Across subtypes, the most widely reported symptoms were numbness (range: 62.2%-89.7%) and hyperalgesia (range: 32.1%-76.9%) and the most commonly prescribed pain analgesics were NSAID (range: 18.2%-57.1%), opioids (range: 0.0%-39.3%), and antiepileptics (range: 18.2%-57.1%). PTN and PSN patients reported the least favorable EQ-5D index scores (M=0.42, SD=0.19) and BPI-Pain Severity scores (M=7.0, SD=1.9), respectively. Those diagnosed with CNP had the least favorable BPI-Pain Interference scores (M=6.0, SD=2.7). Patients with PHN reported the least impairment based on EQ-5D index scores (M=0.60, SD=0.04). Those with pDPN had the most favorable BPI scores (BPI-Pain Severity: M=4.6, SD=2.3; BPI-Pain Interference: M=4.7, SD=2.7).

CONCLUSION

Evaluation of chronic pain patients in Brazil yielded a 14.5% probable NeP prevalence. NSAIDs and opioids were commonly used, and there was a high incidence of NeP-related symptoms with varying levels of dysfunction across subtypes.

Prevalence, Patterns, and Factors Associated with Peripheral Neuropathies among Diabetic Patients at Tertiary Hospital in the Kilimanjaro Region: Descriptive Cross-Sectional Study from North-Eastern Tanzania

OBJECTIVE

Diabetic peripheral neuropathy (DPN) is a common microvascular complication of diabetes mellitus (DM) and may progress to diabetic foot, which frequently leads to amputation and/or disability and death. Data is scanty on the burden of diabetic peripheral neuropathy in Tanzania. The aim of this study was to assess the burden of peripheral neuropathy, its severity, and the associated factors.

METHODS

The study was a cross-sectional hospital-based study and was carried out from October 2017 to March 2018 among adolescent and adult patients attending Kilimanjaro Christian Medical Center (KCMC) diabetes clinic.

RESULTS

A total of 327 diabetic patients, females n=215 (65.7%) and males n=121 (34.3%), were included in the study. The mean age was 57.2 yrs. A total of 238 (72%) had type 2 and 89 (27.2%) had type1 DM. The prevalence of peripheral neuropathy was 72.2% of whom 55% were severe, 19% were moderate, and 26% were mild. The severity of neuropathy increased with the increase in age >40 years (p < 0.001) and increase in body mass index (p<0.001) and duration of diabetes; duration >7 years (p <0.006). The main associated factors were age >40 years, OR 2.8 (1.0-7.7), >60 years, OR 6.4 (2.3-18.2), obesity, OR 6.7 (0.9-27.7), and hypertension, OR 4.3 (2.2-8.2).

CONCLUSION

More than half of the patients included in this study were found to have neuropathy, nearly half of whom presented with the severe form. The main risk factors were increasing age, increasing duration of diabetes, obesity, and hypertension. Diabetic peripheral neuropathy is underdiagnosed in northern Tanzania where screening for neuropathy is not routinely done.

Surgical peripheral nerve decompression for the treatment of painful diabetic neuropathy of the foot - A level 1 pragmatic randomized controlled trial

AIMS

To assess the efficacy of surgical decompression of lower extremity nerves for the treatment of painful diabetic peripheral sensorimotor polyneuropathy (DPN).

METHODS

People with painful diabetic neuropathy were randomized single-blind to a lower extremity decompression surgery (n = 12) or observation (n = 10) for 1 year.

RESULTS

Pain was the primary outcome assessed with 2 measures. The McGill pain visual analogue scores over time changed within the groups (p for time < 0.0001), and changed differently over time within the groups (p for group × time = 0.0138). The NeuroQoL pain sensitivity analysis significantly changed from baseline to 12 months comparing intervention to control (p = 0.0079), and the joint effect of group and time on pain scores was statistically significant (p for group × time = 0.0009). At the study end-point of 12 months, intervention group participants had over 3 times the odds of rating their pain as "better" compared to "unchanged" or "worse" in the control group (p = 0.0177).

CONCLUSIONS

Surgical decompression of lower limb nerves was an effective treatment for decreasing pain in patients with DPN and superimposed nerve compressions.

Automated symptom and treatment side effect monitoring for improved quality of life among adults with diabetic peripheral neuropathy in primary care: a pragmatic, cluster, randomized, controlled trial

AIMS

To evaluate the effectiveness of automated symptom and side effect monitoring on quality of life among individuals with symptomatic diabetic peripheral neuropathy.

METHODS

We conducted a pragmatic, cluster randomized controlled trial (July 2014 to July 2016) within a large healthcare system. We randomized 1834 primary care physicians and prospectively recruited from their lists 1270 individuals with neuropathy who were newly prescribed medications for their symptoms. Intervention participants received automated telephone-based symptom and side effect monitoring with physician feedback over 6 months. The control group received usual care plus three non-interactive diabetes educational calls. Our primary outcomes were quality of life (EQ-5D) and select symptoms (e.g. pain) measured 4-8 weeks after starting medication and again 8 months after baseline. Process outcomes included receiving a clinically effective dose and communication between individuals with neuropathy and their primary care provider over 12 months. Interviewers collecting outcome data were blinded to intervention assignment.

RESULTS

Some 1252 participants completed the baseline measures [mean age (sd): 67 (11.7), 53% female, 57% white, 8% Asian, 13% black, 20% Hispanic]. In total, 1179 participants (93%) completed follow-up (619 control, 560 intervention). Quality of life scores (intervention: 0.658 ± 0.094; control: 0.653 ± 0.092) and symptom severity were similar at baseline. The intervention had no effect on primary [EQ-5D: -0.002 (95% CI -0.01, 0.01), P = 0.623; pain: 0.295 (-0.75, 1.34), P = 0.579; sleep disruption: 0.342 (-0.18, 0.86), P = 0.196; lower extremity functioning: -0.079 (-1.27, 1.11), P = 0.896; depression: -0.462 (-1.24, 0.32); P = 0.247] or process outcomes.

CONCLUSIONS

Automated telephone monitoring and feedback alone were not effective at improving quality of life or symptoms for people with symptomatic diabetic peripheral neuropathy.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02056431).

11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2019

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

Health-related quality of life among adults living with diabetic foot ulcers: a meta-analysis

PURPOSE

To undertake a systematic review of the literature to investigate the HRQOL among adults living with DFUs.

METHODS

A systematic search of the medical and nursing/health content databases including MEDLINE, CINAHL, and PsycINFO was conducted up to November 2018. The methodological quality of each study was assessed independently by all authors using the Joanna Briggs Institute checklist. Data analysis was conducted using the Comprehensive Meta-analysis software. All analyses were performed using random-effects models and heterogeneity was quantified.

RESULTS

A total of 12 studies were included in the review. Overall, the HRQOL of participants in the studies was poor on four of eight subscales in the SF-36: physical functioning (mean = 42.75, SE 1.5); role physical (mean = 20.61, SE 3.4); general health (mean = 39.52, SE 1.7); and vitality (mean = 45.73, SE 2.8). In addition, presence of pain, high levels of C-reactive protein (> 10 mg/L), ulcer size > 5 cm², Ankle Brachial Index < 0.9, high glycosylated haemoglobin and body mass index > 25 kg/m² were associated with poorer HRQOL in people with DFUs.

CONCLUSIONS

This review has provided evidence indicating that people with DFUs have a significantly lower HRQOL. Evidence-based interventions to improve the HRQOL in this group of people is needed.

Prediction of therapeutic response to pregabalin in subjects with neuropathic pain

OBJECTIVE

To evaluate four models based on potential predictors for achieving a response to pregabalin treatment for neuropathic pain (NeP).

METHODS

In total, 46 pain studies were screened, of which 27 NeP studies met the criteria for inclusion in this analysis. Data were pooled from these 27 placebo-controlled randomized trials to assess if baseline characteristics (including mean pain and pain-related sleep interference [PRSI] scores), early clinical response during weeks 1-3 of treatment (change from baseline in pain and PRSI scores), and presence of treatment-emergent adverse events (AEs) were predictive of therapeutic response. Therapeutic response was defined as a ≥30% reduction from baseline in either pain and/or PRSI scores at week 5 with supplemental analyses to predict pain outcomes at weeks 8 and 12. Predictors of Patient Global Impression of Change (PGIC) were also evaluated. Four models were assessed: Random Forest, Logistic Regression, Naïve Bayes, and Partial Least Squares.

RESULTS

The number of pregabalin-treated subjects in the training/test datasets, respectively, were 2818/1407 (30% pain analysis), 2812/1405 (30% sleep analysis), and 2693/1345 (PGIC analysis). All four models demonstrated consistent results, and the most important predictors of treatment outcomes at week 5 and pain outcomes at weeks 8 and 12 were the reduction in pain score and sleep score in the first 1-3 weeks. The presence or absence of the most common AEs in the first 1-3 weeks was not correlated with any treatment outcome.

CONCLUSIONS

Subjects with an early response to pregabalin are more likely to experience an end-of-treatment response.

Living with painful diabetic neuropathy: insights from focus groups into fears and coping strategies

OBJECTIVE

Painful diabetic neuropathy (PDN) is known to negatively affect quality of life. Being physically active is a crucial part of successful diabetes self-management, but regimen adherence is often low. Coping strategies and fears have shown to be related to less physical activity (PA). The aim of the present study was to obtain more in-depth information on psychological risk factors leading to less PA in persons with PDN.

DESIGN

Three semi-structured focus group interviews were conducted with a representative sample of persons with PDN (N = 12). Data were transcribed verbatim and analysed using a hybrid method of thematic analyses and a grounded theory approach.

MAIN OUTCOME MEASURES

Fears and coping strategies related to PA in persons with PDN.

RESULTS

Several specific fears were identified; fear of hypoglycaemia, fear of pain increase, fear of total exhaustion, fear of physical injury, fear of falling, fear of loss of identity, and fear of negative evaluation by others. To cope with these fears, avoidance, remaining active, cognitive distraction, and acceptance strategies were described.

CONCLUSION

In persons with PDN, diabetes-related fears and pain-related fears play a role in less engagement in PA, indicating the need for new methods for improving self-management in persons with PDN.

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.

The Role of Genetic Polymorphisms in Chronic Pain Patients

It is estimated that the total annual financial cost for pain management in the U.S. exceeds 100 billion dollars. However, when indirect costs are included, such as functional disability and reduction in working hours, the cost can reach more than 300 billion dollars. In chronic pain patients, the role of pharmacogenetics is determined by genetic effects on various pain types, as well as the genetic effect on drug safety and efficacy. In this review article, we discuss genetic polymorphisms present in different types of chronic pain, such as fibromyalgia, low back pain, migraine, painful peripheral diabetic neuropathy and trigeminal neuralgia. Furthermore, we discuss the role of CYP450 enzymes involved in metabolism of drugs, which have been used for treatment of chronic pain (amitriptyline, duloxetine, opioids, etc.). We also discuss how pharmacogenetics can be applied towards improving drug efficacy, shortening the time required to achieve therapeutic outcomes, reducing risks of side effects, and reducing medical costs and reliance upon polypharmacy.

Dose Titration of Pregabalin in Patients with Painful Diabetic Peripheral Neuropathy: Simulation Based on Observational Study Patients Enriched with Data from Randomized Studies

INTRODUCTION

Achieving a therapeutic response to pregabalin in patients with painful diabetic peripheral neuropathy (pDPN) requires adequate upward dose titration. Our goal was to identify relationships between titration and response to pregabalin in patients with pDPN.

METHODS

Data were integrated from nine randomized, placebo-controlled clinical trials as well as one 6-week open-label observational study conducted by 5808 physicians (2642 patients with pDPN) in standard outpatient settings in Germany. These studies evaluated pregabalin for treatment of pDPN. Using these data, we examined "what if" scenarios using a microsimulation platform that integrates data from randomized and observational sources as well as autoregressive-moving-average with exogenous inputs models that predict pain outcomes, taking into account weekly changes in pain, sleep interference, dose, and other patient characteristics that were unchanging.

RESULTS

Final pain levels were significantly different depending on dose changes (P < 0.0001), with greater proportions improving with upward titration regardless of baseline pain severity. Altogether, 78.5% of patients with pDPN had 0-1 dose change, and 15.2% had ≥ 2 dose changes. Simulation demonstrated that the 4.8% of inadequately titrated patients who did not improve/very much improve their pain levels would have benefited from ≥ 2 dose changes. Patient satisfaction with tolerability (range 90.3-96.2%) was similar, regardless of baseline pain severity, number of titrations, or extent of improvement, suggesting that tolerability did not influence treatment response patterns.

CONCLUSION

Upward dose titration reduced pain in patients with pDPN who actually received it. Simulation also predicted pain reduction in an inadequately titrated nonresponder subgroup of patients had they actually received adequate titration. The decision not to uptitrate must have been driven by factors other than tolerability.

FUNDING

Pfizer, Inc.

10. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2018

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

Overcoming barriers to diabetic polyneuropathy management in primary care

Diabetic polyneuropathy is a highly prevalent and costly complication of diabetes that is frequently underdiagnosed and undertreated in primary care settings. In this article, we discuss challenges in the management of diabetic polyneuropathy symptoms, including diagnostic complexity, the limited efficacy and high side effect rates associated with available treatments and the time constrained primary care visit. We call for the development of novel patient-centric, system-level strategies that engage patients between physician visits in order to facilitate timely communication of symptoms and treatment response and to promote patient-centered care.

Patient navigation to improve diabetes outpatient care at a safety-net hospital: a retrospective cohort study

BACKGROUND

Recent emphasis on value based care and population management, such as Accountable Care Organizations in the United States, promote patient navigation to improve the quality of care and reduce costs. Evidence supporting the efficacy of patient navigation for chronic disease care is limited. The objective of this study was to evaluate the effect of a patient navigation program on medical and administrative outcomes among patients with diabetes in an urban, safety-net hospital clinic setting.

METHODS

A retrospective cohort study with pre- and post-intervention periods was conducted. Eligible patients were those with A1C ≥ 8.5% and at least one appointment no-show in the previous 12 months. The intervention and reference groups were balanced on observed characteristics and baseline outcome levels using propensity score matching. The effect of patient navigation was isolated using the difference-in-differences approach. Primary outcomes were A1C, low-density lipoprotein cholesterol, triglycerides, random urine microalbumin, the number of scheduled appointments, clinic visits, emergency visits, and inpatient stays, and the percentage of arrivals, cancellations, and no-shows to scheduled appointments.

RESULTS

Of 797 eligible patients, 328 entered the navigation program. Matching reduced the sample size to 392 individuals (196 in each group). Patient navigation resulted in improved A1C (-1.1 percentage points; p < .001), more scheduled appointments (+ 5.3 per year; p < .001), more clinic visits (+6.4 per year; p < .001), more arrivals to scheduled appointments (+7.4 percentage points; p = .009) and fewer no-shows (-9.8 percentage points; p < .001).

CONCLUSIONS

Navigation was associated with improved glycemic control and better clinic engagement among patients with diabetes. Further research is important to identify what features of navigation in diabetes care are critical to achieving success and to understand navigators' role in other settings.

The prevalence of probable neuropathic pain in the US: results from a multimodal general-population health survey

Background

The prevalence of neuropathic pain (NeP) has been estimated within specific health conditions; however, there are no published data on its broad prevalence in the US. The current exploratory study addresses this gap using the validated PainDetect questionnaire as a screener for probable NeP in a general-population health survey conducted with a multimodal recruitment strategy to maximize demographic representativeness.

Materials and methods

Adult respondents were recruited from a combination of Internet panels, telephone lists, address lists, mall-based interviews, and store-receipt invitations using a random stratified-sampling framework, with strata defined by age, sex, and race/ethnicity. Older persons and minorities were oversampled to improve prevalence estimates. Results were weighted to match the total adult US population using US Census data. Demographic information was collected, and respondents who experienced physical pain in the past 12 months completed the PainDetect and provided additional pain history. A cutoff score of 19 or greater on the PainDetect was used to define probable NeP.

Results

A total of 24,925 respondents (average response rate 2.5%) provided demographic data (52.2% female, mean age 51.5 years); 15,751 respondents reported pain (63.7%), of which 2,548 (15.7%, 95% confidence interval 14.9%-16.5%) had probable NeP based on the PainDetect, which was 10% (95% confidence interval 9.5%-10.5%) of all respondents. Among those reporting pain, the prevalence of probable NeP among Blacks and Hispanics was consistently higher than Whites in each age- and sex group. The highest prevalence among those with pain was among male Hispanics 35-44 years (32.4%) and 45-54 years (24.2%) old. The most commonly used medications reported by those with probable NeP were nonsteroidal anti-inflammatory drugs (44.2%), followed by weak opioids (31.7%), antiepileptics (10.9%), and strong opioids (10.9%).

Conclusion

This is the first study to provide an estimate of the prevalence of probable NeP in the US, showing significant variation by age and ethnicity.

HIV Distal Neuropathic Pain Is Associated with Smaller Ventral Posterior Cingulate Cortex

Objective

. Despite modern antiretroviral therapy, HIV-associated neuropathy is one of the most prevalent, disabling and treatment-resistant complications of HIV disease. The presence and intensity of distal neuropathic pain is not fully explained by the degree of peripheral nerve damage. A better understanding of brain structure in HIV distal neuropathic pain may help explain why some patients with HIV neuropathy report pain while the majority does not. Previously, we reported that more intense distal neuropathic pain was associated with smaller total cerebral cortical gray matter volumes. The objective of this study was to determine which parts of the cortex are smaller.

Methods

. HIV positive individuals with and without distal neuropathic pain enrolled in the multisite (N = 233) CNS HIV Antiretroviral Treatment Effects (CHARTER) study underwent structural brain magnetic resonance imaging. Voxel-based morphometry was used to investigate regional brain volumes in these structural brain images.

Results

. Left ventral posterior cingulate cortex was smaller for HIV positive individuals with versus without distal neuropathic pain (peak P  = 0.017; peak t = 5.15; MNI coordinates x = -6, y = -54, z = 20). Regional brain volumes within cortical gray matter structures typically associated with pain processing were also smaller for HIV positive individuals having higher intensity ratings of distal neuropathic pain.

Conclusions

. The posterior cingulate is thought to be involved in inhibiting the perception of painful stimuli. Mechanistically a smaller posterior cingulate cortex structure may be related to reduced anti-nociception contributing to increased distal neuropathic pain.

Neuropathic pain: a narrative review of etiology, assessment, diagnosis, and treatment for primary care providers

BACKGROUND

Neuropathic pain (NeP) is a distinct type of chronic pain that is a direct result of damage to the nervous system itself. Studies have shown that training on the topic of chronic pain in medical schools is lacking and many practitioners are not confident in their ability to effectively manage patients with such pain.

AIMS

The purpose of this narrative review is to provide a brief high-level overview of NeP for primary healthcare providers that includes a discussion of mechanisms, prevalence, burden, assessment, and treatment. The information provided here should help primary care providers better understand this type of chronic pain.

An integrated perspective on diabetic, alcoholic, and drug-induced neuropathy, etiology, and treatment in the US

Neuropathic pain (NeuP) is a syndrome that results from damaged nerves and/or aberrant regeneration. Common etiologies of neuropathy include chronic illnesses and medication use. Chronic disorders, such as diabetes and alcoholism, can cause neuronal injury and consequently NeuP. Certain medications with antineoplastic effects also carry an exquisitely high risk for neuropathy. These culprits are a few of many that are fueling the NeuP epidemic, which currently affects 7%-10% of the population. It has been estimated that approximately 10% and 7% of US adults carry a diagnosis of diabetes and alcohol disorder, respectively. Despite its pervasiveness, many physicians are unfamiliar with adequate treatment of NeuP, partly due to the few reviews that are available that have integrated basic science and clinical practice. In light of the recent Centers for Disease Control and Prevention guidelines that advise against the routine use of μ-opioid receptor-selective opioids for chronic pain management, such a review is timely. Here, we provide a succinct overview of the etiology and treatment options of diabetic and alcohol- and drug-induced neuropathy, three different and prevalent neuropathies fusing the combined clinical and preclinical pharmacological expertise in NeuP of the authors. We discuss the anatomy of pain and pain transmission, with special attention to key ion channels, receptors, and neurotransmitters. An understanding of pain neurophysiology will lead to a better understanding of the rationale for the effectiveness of current treatment options, and may lead to better diagnostic tools to help distinguish types of neuropathy. We close with a discussion of ongoing research efforts to develop additional treatments for NeuP.

Improvement in Neuropathy Specific Quality of Life in Patients with Diabetes after Vitamin D Supplementation

OBJECTIVE

To assess the effect of vitamin D supplementation on neuropathy specific quality of life (NeuroQoL) in patients with painful diabetic neuropathy.

METHODS

This prospective, open label study was conducted between June 2012 and April 2013. Patients with symptomatic diabetic neuropathy were given a single dose of 600,000 IU intramuscular vitamin D, and NeuroQol was assessed at baseline and at five follow-up visits every 4 weeks.

RESULTS

Of 143 participants, 41.3% were vitamin D deficient (vitamin D < 20 ng/ml). Treatment with vitamin D resulted in a significant increase in 25(OH)D (P < 0.0001) and a significant improvement in the NeuroQoL subscale score for emotional distress (P = 0.04), with no significant change in the other NeuroQoL domains of painful symptoms and paresthesia, loss of temperature and touch sensation, unsteadiness, limitation in daily activities, and interpersonal problems. There was a significant reduction in patient perception about foot problems on QoL of "quite a lot" (P < 0.05) and "very much" (P < 0.0001) with a significant reduction in the baseline response of having a "poor" QoL from 5.2% to 0.7% (P < 0.0001) and an increase in the response of an "excellent QoL" from 1.5% to 7.4% (P < 0.0001).

CONCLUSION

Vitamin D is effective in improving quality of life in patients with painful diabetic neuropathy.

Diabetic peripheral neuropathic pain is a stronger predictor of depression than other diabetic complications and comorbidities

AIMS

To investigate the independent effect on depression of painless diabetic polyneuropathy, painful diabetic polyneuropathy, and general and diabetes-related comorbidities.

METHODS

In 181 patients, the presence of painless diabetic polyneuropathy, painful diabetic polyneuropathy, comorbidities and depression was assessed using the Michigan Neuropathy Screening Instrument Questionnaire, the Michigan Diabetic Neuropathy Score, nerve conduction studies, the Douleur Neuropathique en 4 Questions, the Charlson Comorbidity Index and the Beck Depression Inventory-II.

RESULTS

In all, 46 patients met the criteria of confirmed painless diabetic polyneuropathy and 25 of painful diabetic polyneuropathy. Beck Depression Inventory-II scores indicative of mild-moderate-severe depression were reached in 36 patients (19.7%). In a multiple logistic regression analysis (including age, sex, body mass index, being unemployed, duration, haemoglobin A1c, insulin treatment, systolic blood pressure, nephropathy, retinopathy, Charlson Comorbidity Index and painful diabetic polyneuropathy), female sex (odds ratio: 5.9, p = 0.005) and painful diabetic polyneuropathy (odds ratio: 4.6, p = 0.038) were the only independent predictors of depression. Multiple regression analysis, including Douleur Neuropathique en 4 Questions and Michigan Diabetic Neuropathy Score instead of painful diabetic polyneuropathy, showed that Douleur Neuropathique en 4 Questions, in addition to female sex, was a significant predictor of depressive symptoms severity (p =0.005).

CONCLUSION

Painful diabetic polyneuropathy is a greater determinant of depression than other diabetes-related complications and comorbidities. Painful symptoms enhance depression severity more than objective insensitivity.

Administration of Traditional Chinese Blood Circulation Activating Drugs for Microvascular Complications in Patients with Type 2 Diabetes Mellitus

Traditional Chinese medicine (TCM) is an important complementary strategy for treating diabetes mellitus (DM) in China. Traditional Chinese blood circulation activating drugs are intended to guide an overall approach to the prevention and treatment of microvascular complications of DM. The core mechanism is related to the protection of the vascular endothelium and the basement membrane. Here, we reviewed the scientific evidence underpinning the use of blood circulation activating drugs to prevent and treat DM-induced microvascular complications, including diabetic nephropathy (DN), diabetic peripheral neuropathy (DPN), and diabetic retinopathy (DR). Furthermore, we summarized the effects and mechanism of TCM on improving blood rheology, inhibiting aggregation of platelet, forming advanced glycation end products (AGEs), regulating oxidative stress, reducing blood fat, and improving lipid metabolism. The paper provides a new theoretical basis for the clinical practice of TCM in the prevention and treatment of DM and its microvascular complications.

Pain modulation from the brain during diabetic neuropathy: Uncovering the role of the rostroventromedial medulla

Diabetic neuropathy has a profound impact in the quality of life of patients who frequently complain of pain. The mechanisms underlying diabetic neuropathic pain (DNP) are no longer ascribed only to damage of peripheral nerves. The effects of diabetes at the central nervous system are currently considered causes of DPN. Management of DNP may be achieved by antidepressants that act on serotonin (5-HT) uptake, namely specific serotonin reuptake inhibitors. The rostroventromedial medulla (RVM) is a key pain control center involved in descending pain modulation at the spinal cord through local release of 5-HT and plays a peculiar role in the balance of bidirectional control (i.e. inhibitory and facilitatory) from the brain to the spinal cord. This review discusses recently uncovered neurobiological mechanisms that mediate nociceptive modulation from the RVM during diabetes installation. In early phases of the disease, facilitation of pain modulation from the RVM prevails through a triplet of mechanisms which include increase in serotonin expression at the RVM and consequent rise of serotonin levels at the spinal cord and upregulation of local facilitatory 5HT3 receptors, enhancement of spontaneous activity of facilitatory RVM neurons and up-regulation of the expression of transient receptor potential vanilloid type 1 (TRPV1) receptor. With the progression of diabetes the alterations in the RVM increase dramatically, with oxidative stress and neuronal death associated to microglia-mediated inflammation. In a manner similar to other central areas, like the thalamus, the RVM is likely to be a "pain generator/amplifier" during diabetes, accounting to increase DNP. Early interventions in DNP prevention using strategies that simultaneously tackle the exacerbation of 5-HT3 spinal receptors and of microglial RVM activity, namely those that increase the levels of anti-inflammatory cytokines, should be considered in the future of DNP treatment.

Pain Relief and Health-Related Quality-of-Life Improvement After Microsurgical Decompression of Entrapped Peripheral Nerves in Patients With Painful Diabetic Peripheral Neuropathy

Surgery had been shown to be effective for superimposed peripheral nerve entrapment syndrome in patients with diabetic peripheral neuropathy (DPN), with pain relief and sensation restored. Few studies, however, have reported the quality-of-life outcomes of surgery for the treatment of painful DPN (PDPN). The objective of the present study was to evaluate the effects of microsurgical decompression of multiple entrapped peripheral nerves on pain and health-related quality of life in patients with refractory PDPN of the lower limbs. Eleven patients with intractable PDPN of the lower limbs were recruited for the present study. All the patients underwent microsurgical decompression of the common peroneal nerve, deep peroneal nerve, and posterior tibial nerve. The pain intensity was assessed using the visual analog scale and health-related quality of life was measured using the short-form 36-item quality-of-life survey. Six (54.6%) patients experienced >50% pain relief (both daytime pain and nocturnal pain) at 2 weeks after the decompression procedure and 8 (72.7%) patients at 24 months postoperatively. Two (18.2%) patients experienced a >50% decrease in peak pain at the 2 weeks after the procedure and 8 (72.7%) patients at 24 months. Additionally, the scores from the short-form 36-item quality-of-life survey were significantly improved in the following 2 domains: bodily pain and general health at 2 weeks after the decompression procedure. Also, at 24 months postoperatively, 6 domains had significantly improved, including physical function, bodily pain, general health, social function, role emotional, and mental health. No significant side effects were recorded during the study. Microsurgical decompression of peripheral nerves is an effective and safe therapy for intractable PDPN with superimposed nerve compression.

Mapping painDETECT, a neuropathic pain screening tool, to the EuroQol (EQ-5D-3L)

PURPOSE

To map relationships between painDETECT, a neuropathic pain (NeP) screening tool, and EQ-5D-3L health status in a real-world setting.

METHODS

Patients with physician-confirmed NeP and painDETECT score classifications of nociceptive (n = 79), transitional (n = 141), and NeP (n = 386) completed the EuroQol (EQ-5D-3L), which evaluates Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression with three ordinal response levels ("no problem," "some problems," or "extreme problems/unable to do"), and has a health status thermometer (0 = worst health, 100 = perfect health). Multiple linear and logistic regressions were performed (adjusted for age, gender, race, ethnicity, time since NeP diagnosis, number of comorbidities, NeP conditions).

RESULTS

Unadjusted mean (±SD) EQ-5D-3L thermometer scores showed poorer health status across painDETECT classifications from nociceptive (67.3 ± 22.1) to transitional (62.3 ± 20.9) to NeP (53.7 ± 21.8), as did utility scores, 0.695 ± 0.206, 0.615 ± 0.216, and 0.506 ± 0.216. In general, the highest odds of health problems were observed for NeP and the lowest for nociceptive, e.g., the NeP group was 6.2 (95 % confidence interval 3.4-11.4) times as likely to have a more severe problem of Usual Activities compared with the nociceptive group. Relative to nociceptive and transitional, NeP had lower adjusted mean thermometer scores, by 12.1 (P < 0.0001) and 7.8 (P = 0.0004) points, respectively, and lower mean utility scores by 0.157 (P < 0.0001) and 0.092 points (P < 0.0001).

CONCLUSIONS

This study, the first to map relationships between painDETECT and the EQ-5D-3L in a real-world setting, indicates that the patient burden with respect to pain classification can be characterized and quantified by decrements in health status overall and in specific domains. These data support the psychometric soundness of painDETECT, enhancing its use in pain management.

Characterizing individual painDETECT symptoms by average pain severity

Background

painDETECT is a screening measure for neuropathic pain. The nine-item version consists of seven sensory items (burning, tingling/prickling, light touching, sudden pain attacks/electric shock-type pain, cold/heat, numbness, and slight pressure), a pain course pattern item, and a pain radiation item. The seven-item version consists only of the sensory items. Total scores of both versions discriminate average pain-severity levels (mild, moderate, and severe), but their ability to discriminate individual item severity has not been evaluated.

Methods

Data were from a cross-sectional, observational study of six neuropathic pain conditions (N=624). Average pain severity was evaluated using the Brief Pain Inventory-Short Form, with severity levels defined using established cut points for distinguishing mild, moderate, and severe pain. The Wilcoxon rank sum test was followed by ridit analysis to represent the probability that a randomly selected subject from one average pain-severity level had a more favorable outcome on the specific painDETECT item relative to a randomly selected subject from a comparator severity level.

Results

A probability >50% for a better outcome (less severe pain) was significantly observed for each pain symptom item. The lowest probability was 56.3% (on numbness for mild vs moderate pain) and highest probability was 76.4% (on cold/heat for mild vs severe pain). The pain radiation item was significant (P<0.05) and consistent with pain symptoms, as well as with total scores for both painDETECT versions; only the pain course item did not differ.

Conclusion

painDETECT differentiates severity such that the ability to discriminate average pain also distinguishes individual pain item severity in an interpretable manner. Pain-severity levels can serve as proxies to determine treatment effects, thus indicating probabilities for more favorable outcomes on pain symptoms.

Efficacy and Safety of Pregabalin in the Treatment of Patients With Painful Diabetic Peripheral Neuropathy and Pain on Walking

OBJECTIVES

This randomized, double-blind, placebo-controlled, multicenter, 2-period crossover study (two 6-week treatment periods separated by a 2-week washout period) evaluated the efficacy and safety of pregabalin (150 to 300 mg/d) for treatment of pain and pain on walking in patients with painful diabetic peripheral neuropathy (DPN) who experienced pain while walking.

METHODS

Co-primary efficacy endpoints were: (1) mean pain score (last 7 daily pain diary scores, 0 to 10 numeric rating scale at end of each treatment period) and (2) DPN pain on walking (0 to 10 numeric rating scale immediately after walking 50 feet [15.2 m] on flat surface). Secondary endpoints included other pain parameters, patient-reported sleep, health-related quality of life, and safety measures.

RESULTS

Two hundred three patients were treated (pregabalin, n=198; placebo, n=186), with no statistically significant treatment difference for pregabalin versus placebo in the co-primary efficacy endpoints, mean DPN pain (P=0.0656) and mean DPN pain on walking (P=0.412). A carryover effect was observed. Analysis of co-primary endpoints for period 1 showed significant treatment difference for DPN pain (P=0.034) and DPN pain on walking (P=0.001). Treatment with pregabalin resulted in significant improvements versus placebo on prespecified patient global impression of change (end of period 1; P=0.002), and sleep interference rating scale (end of period 2; P=0.011). Adverse events were more frequent with pregabalin than with placebo and caused discontinuation in 13 (6.6%) pregabalin patients versus 5 (2.7%) placebo patients.

DISCUSSION

Failure to meet the co-primary objectives may be related to carryover effect from period 1 to period 2, lower pregabalin dose (150 to 300 mg/d), and/or placebo response in painful DPN.

The Diabetes Telephone Study: Design and challenges of a pragmatic cluster randomized trial to improve diabetic peripheral neuropathy treatment

BACKGROUND

Challenges to effective pharmacologic management of symptomatic diabetic peripheral neuropathy include the limited effectiveness of available medicines, frequent side effects, and the need for ongoing symptom assessment and treatment titration for maximal effectiveness. We present here the rationale and implementation challenges of the Diabetes Telephone Study, a randomized trial designed to improve medication treatment, titration, and quality of life among patients with symptomatic diabetic peripheral neuropathy.

METHODS

We implemented a pragmatic cluster randomized controlled trial to test the effectiveness of an automated interactive voice response tool designed to provide physicians with real-time patient-reported data about responses to newly prescribed diabetic peripheral neuropathy medicines. A total of 1834 primary care physicians treating patients in the diabetes registry at Kaiser Permanente Northern California were randomized into the intervention or control arm. In September 2014, we began identification and recruitment of patients assigned to physicians in the intervention group who receive three brief interactive calls every 2 months after a medication is prescribed to alleviate diabetic peripheral neuropathy symptoms. These calls provide patients with the opportunity to report on symptoms, side effects, self-titration of medication dose and overall satisfaction with treatment. We plan to compare changes in self-reported quality of life between the intervention group and patients in the control group who receive three non-interactive automated educational phone calls.

RESULTS

Successful implementation of this clinical trial required robust stakeholder engagement to help tailor the intervention and to address pragmatic concerns such as provider time constraints. As of 27 October 2015, we had screened 2078 patients, 1447 of whom were eligible for participation. We consented and enrolled 1206 or 83% of those eligible. Among those enrolled, 53% are women and the mean age is 67 (standard deviation = 12) years. The racial ethnic make-up is 56% White, 8% Asian, 13% Black or African American, and 19% Hispanic or Latino.

CONCLUSION

Innovative strategies are needed to guide improvements in healthcare delivery for patients with symptomatic diabetic peripheral neuropathy. This trial aims to assess whether real-time collection and clinical feedback of patient treatment experiences can reduce patient symptom burden. Implementation of a clinical trial closely involving clinical care required researchers to partner with clinicians. If successful, this intervention provides a critical information feedback loop that would optimize diabetic peripheral neuropathy medication titration through widely available interactive voice response technology.

Contributions of Comorbid Diabetes to Sleep Characteristics, Daytime Symptoms, and Physical Function Among Patients With Stable Heart Failure

BACKGROUND

Diabetes mellitus (DM) and heart failure (HF) are often comorbid. Sleep disturbances, poor physical functioning, and high levels of daytime symptoms are prevalent and contribute to poor quality of life in both populations. However, little is known about the independent and additive effects of comorbid DM on sleep, physical function, and daytime symptoms among patients with HF.

OBJECTIVE

The aim of this study was to investigate the extent to which comorbid DM confers independent and additive effects on sleep disturbance, physical functioning, and symptoms among patients with stable HF.

METHODS

This secondary analysis was conducted on a sample of 173 stable class II to IV HF patients. Self-report and polysomnography were used to measure sleep quality, objective sleep characteristics, and sleep-disordered breathing. Physical function measures included wrist actigraphy, the 6-minute walk test (6MWT), and the Medical Outcomes Study 36-item Short Form physical component summary score. Fatigue, sleepiness, and depression were also measured. Univariate analyses and hierarchical regression models were computed.

RESULTS

The sample included 173 (n = 119/68% HF and n = 54/32% HF plus DM) patients (mean [SD] age, 60.4 [16.1] years). In analyses adjusted for age, gender, body mass index, and New York Heart Association classification, the HF patients with DM had longer sleep latency and spent a greater percentage of time awake after sleep onset than the HF patients who did not have DM (all P < 0.05). There were no statistically significant differences in Respiratory Disturbance Index or self-reported sleep quality. Sleep duration was low in both groups. The patients with DM had shorter 6MWT distance, lower ratio of daytime to nighttime activity, as well as lower general health and self-reported physical function. Hierarchical regression models revealed that age and DM were the only significant correlates of the sleep variables, whereas age, gender, New York Heart Association class, and DM were all associated with 6MWT distance.

CONCLUSIONS

Comorbid DM contributes independent and additive effects on sleep disturbances and poor physical functioning in patients with stable HF.

The efficacy of pregabalin in patients with moderate and severe pain due to diabetic peripheral neuropathy

Objective To compare the therapeutic response to pregabalin in patients with moderate or severe painful diabetic peripheral neuropathy (pDPN). Research design and methods Data were pooled from 11 placebo-controlled trials to evaluate the efficacy of pregabalin flexible or fixed dose (150, 300 or 600 mg/day) in pDPN patients with mean baseline pain scores of ≥4 to <7 (moderate) or ≥7 to ≤10 (severe). Last observation carried forward imputation was used. Study number/ClinicalTrials.gov identifier 1008-014/-, 1008-029/-, 1008-040/-, 1008-131/-, 1008-149/-, 1008-000-155/-, A0081030/NCT00156078, A0081060/NCT00159679, A0081071/NCT00143156, A0081081/NCT00301223, A0081163/NCT00553475. Main outcome measures Pregabalin-mediated change in pain, pain-related sleep interference (PRSI) and patient global impression of change (PGIC) were compared versus placebo and between moderate and severe pain cohorts. Adverse events (AEs) were reported. Results At baseline, 1816 patients had moderate pain (pregabalin, n = 1189) and 1119 patients had severe pain (pregabalin, n = 720). Pregabalin significantly reduced pain scores at endpoint compared with placebo when patients of all pain levels were combined (all doses; p < 0.05). In the moderate and severe pain cohorts, pregabalin treatment (300, 600 mg/day or flexible) significantly reduced mean pain scores at endpoint compared with placebo (p < 0.01). Pain reduction was greatest in patients with severe baseline pain compared with moderate baseline pain (pregabalin 300, 600 mg/day or flexible; p < 0.0001). Pregabalin improved PRSI and PGIC in the moderate and severe cohorts compared with placebo. The greatest improvement in PRSI also occurred in the severe cohort. Treatment-emergent AEs, most commonly dizziness, somnolence and peripheral edema, occurred more frequently in patients treated with pregabalin compared with placebo. Conclusions Pregabalin was effective in pDPN patients with both moderate and severe baseline pain. Patients with severe pain exhibited greater improvements in pain and PRSI than patients with moderate pain. Pain severity may, in part, predict therapeutic response to pregabalin.

Communication Barriers and the Clinical Recognition of Diabetic Peripheral Neuropathy in a Diverse Cohort of Adults: The DISTANCE Study

The purpose of this study was to explore communication barriers as independent predictors and potential mediators of variation in clinical recognition of diabetic peripheral neuropathy (DPN). In this cross-sectional analysis, we estimated the likelihood of having a DPN diagnosis among 4,436 patients with DPN symptoms. We controlled for symptom frequency, demographic and clinical characteristics, and visit frequency using a modified Poisson regression model. We then evaluated 4 communication barriers as independent predictors of clinical documentation and as possible mediators of racial/ethnic differences: difficulty speaking English, not talking to one's doctor about pain, limited health literacy, and reports of suboptimal patient-provider communication. Difficulty speaking English and not talking with one's doctor about pain were independently associated with not having a diagnosis, though limited health literacy and suboptimal patient-provider communication were not. Limited English proficiency partially attenuated, but did not fully explain, racial/ethnic differences in clinical documentation among Chinese, Latino, and Filipino patients. Providers should be encouraged to talk with their patients about DPN symptoms, and health systems should consider enhancing strategies to improve timely clinical recognition of DPN among patients who have difficult speaking English. More work is needed to understand persistent racial/ethnic differences in diagnosis.

The Need for Improved Management of Painful Diabetic Neuropathy in Primary Care

The provision of care for patients with type II diabetes in primary care must involve assessing patients for peripheral neuropathy of the feet. Objectives. This paper will demonstrate that painful diabetic neuropathy (PDN) is poorly assessed for and treated in primary care. Methods. A critical analysis of research will be conducted to identify the prevalence and impact of PDN among individuals with type II diabetes. Results. Research evidence and best practice guidelines are widely available in supporting primary care practitioners to better assess for and treat PDN. However, the lack of knowledge, awareness, and implementation of such research and guidelines prevents patients with PDN from receiving appropriate care. Discussion. Much international research exists on the prevalence and impact of PDN in primary care; however, Canadian research is lacking. Furthermore, the quantity and quality of research on treatment modalities for PDN are inadequate. Finally, current research and guidelines on PDN management are inadequately implemented in the clinical setting. Conclusion. The undertreatment of PDN has significant implications on the individual, family, and society. Healthcare practitioners must be more aware of and better implement current research and guidelines into practice to resolve this clinical issue.

Vitamin D for the treatment of painful diabetic neuropathy

OBJECTIVE

To assess the effect of high-dose vitamin D in patients with painful diabetic neuropathy.

METHODS

A single intramuscular dose of 600 000 IU vitamin D was administered, and the effects on metabolic parameters and neuropathic pain assessed over 20 weeks.

RESULTS

143 participants with predominantly type 2 diabetes, aged 52.31±11.48 years, with a Douleur Neuropathique 4 (DN4) score (3.0±1.8), total McGill pain score (21.2±14.9), and Short Form McGill Pain Questionnaire (SFMPQ) score (2.1±0.9), were enrolled. The baseline 25-hydroxyvitamin D (25(OH)D) level was 31.7±23.3 ng/mL and 58 (40.5%) patients showed evidence of vitamin D deficiency (25(OH)D<20 ng/mL). Intramuscular administration of vitamin D resulted in a significant increase in 25(OH)D (46.2±10.2 ng/mL, p<0.0001) and a reduction in positive symptoms on the DN4 (p<0.0001), total pain score (p<0.0001), and SFMPQ (p<0.0001).

CONCLUSIONS

Treatment with a single intramuscular dose of 600 000 IU of vitamin D in patients with painful diabetic neuropathy is associated with a significant decrease in the symptoms of painful diabetic neuropathy.

TRIAL REGISTRATION NUMBER

BIDE-12/2014.

Nutritional management of patients with diabetic peripheral neuropathy with L-methylfolate-methylcobalamin-pyridoxal-5-phosphate: results of a real-world patient experience trial

OBJECTIVE

Current therapies for diabetic peripheral neuropathy with pain mask the painful symptoms while the underlying pathology continues to progress. This study assessed changes in symptoms and quality of life in patients taking a novel prescription medical food, L-methylfolate-methylcobalamin-pyridoxal-5-phosphate (LMF-MC-PP, Metanx ), intended to address the underlying metabolic needs of patients with diabetic peripheral neuropathy.

RESEARCH DESIGN AND METHODS

Between November 2010 and April 2012, patients rated their experiences before and after using LMF-MC-PP through an automated telephone system that included symptomatic items from the Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire and questions related to quality of life and medication satisfaction.

RESULTS

A total of 544 patients participated in the study. Patients reported a mean reduction of 35% in NTSS-6 scores from after 12 weeks on LMF-MC-PP. Mean (standard deviation) score was reduced by 1.5 (1.8) at 12 weeks from a baseline of 4.3 (1.5) (p < 0.05). Patients achieved significant reductions in self-reported disruptions in work/school activities, social life, and family life, respectively. Overall pain rating decreased by 32% (p < 0.05). Patients previously treated with medications reported a 52% improvement in medication satisfaction (p < 0.05).

CONCLUSIONS

In a real-world clinical setting, patients with diabetic peripheral neuropathy treated with LMF-MC-PP achieved significant improvements in total symptom score (NTSS-6) and in quality of life and functioning, together with greater medication satisfaction. A limitation of this study was the use of a survey instrument to collect data on patient outcomes.

Are there different predictors of analgesic response between antidepressants and anticonvulsants in painful diabetic neuropathy?

BACKGROUND

To investigate baseline demographics and disease characteristics as predictors of the analgesic effect of duloxetine and pregabalin on diabetic peripheral neuropathic pain (DPNP).

METHODS

Based on data from the COMBO-DN study, a multinational clinical trial in DPNP, the potential impact of baseline characteristics on pain relief after 8-week monotherapy with 60 mg/day duloxetine or 300 mg/day pregabalin was assessed using analyses of covariance. Subgroups of interest were characterized regarding their baseline characteristics and efficacy outcomes.

RESULTS

A total of 804 patients were evaluated at baseline. A significant interaction with treatment was observed in the mood symptom subgroups with a larger pain reduction in duloxetine-treated patients having no mood symptoms [Hospital Anxiety and Depression Scale (HADS) depression or anxiety subscale score <11; -2.33 (duloxetine); -1.52 (pregabalin); p = 0.024]. There were no significant interactions between treatment for subgroups by age (<65 or ≥65 years), gender, baseline pain severity [Brief Pain Inventory Modified Short Form (BPI-MSF) average pain <6 or ≥6], diabetic neuropathy duration (≤2 or >2 years), baseline haemoglobin A1c (HbA1c) (<8% or ≥8%), presence of comorbidities and concomitant medication use.

CONCLUSIONS

Our analyses suggest that the efficacy of duloxetine and pregabalin for initial 8-week treatment in DPNP was consistent across examined subgroups based on demographics and disease characteristics at baseline except for the presence of mood symptoms. Duloxetine treatment appeared to be particularly beneficial in DPNP patients having no mood symptoms.

Burden of HIV-Related Neuropathic Pain in the United States

BACKGROUND

HIV-related neuropathic pain (HIV-NeP) is common; however, the burden of HIV-NeP is not well-understood.

METHODS

The cross-sectional study aimed to characterize the HIV-NeP burden. A total of 103 patients with HIV-NeP recruited during routine office visits completed a questionnaire to assess patient-reported outcomes, including pain severity, health status, sleep, mood, and lost productivity. Physicians completed a 6-month retrospective chart review.

RESULTS

The sample was predominantly male and not employed for pay. A majority (75.7%) of patients experienced moderate or severe pain. Pain interference, general health, physical health, and depression were worse among patients with more severe pain (all Ps < .006). Most (87.4%) patients were prescribed at least 1 medication for NeP. HIV-related neuropathic pain was associated with 36.1% work impairment. Adjusted annualized costs increased with increasing pain severity (P < .0001).

CONCLUSION

The impact of HIV-NeP on health status, physical function, and depression increases with severity, resulting in substantial clinical and economic burden.

Peripheral Neuropathy: A Practical Approach to Diagnosis and Symptom Management

Peripheral neuropathy is one of the most prevalent neurologic conditions encountered by physicians of all specialties. Physicians are faced with 3 distinct challenges in caring for patients with peripheral neuropathy: (1) how to efficiently and effectively screen (in less than 2 minutes) an asymptomatic patient for peripheral neuropathy when they have a disorder in which peripheral neuropathy is highly prevalent (eg, diabetes mellitus), (2) how to clinically stratify patients presenting with symptoms of neuropathy to determine who would benefit from specialty consultation and what testing is appropriate for those who do not need consultation, and (3) how to treat the symptoms of painful peripheral neuropathy. In this concise review, we address these 3 common clinical scenarios. Easily defined clinical patterns of involvement are used to identify patients in need of neurologic consultation, the yield of laboratory and other diagnostic testing is reviewed for the evaluation of length-dependent, sensorimotor peripheral neuropathies (the most common form of neuropathy), and an algorithmic approach with dosing recommendations is provided for the treatment of neuropathic pain associated with peripheral neuropathy.

Botulinum Toxin Type A for the Treatment of Neuropathic Pain in Neuro-Rehabilitation

Pain is a natural protective mechanism and has a warning function signaling imminent or actual tissue damage. Neuropathic pain (NP) results from a dysfunction and derangement in the transmission and signal processing along the nervous system and it is a recognized disease in itself. The prevalence of NP is estimated to be between 6.9% and 10% in the general population. This condition can complicate the recovery from stroke, multiple sclerosis, spinal cord lesions, and several neuropathies promoting persistent disability and poor quality of life. Subjects suffering from NP describe it as burning, itching, lancing, and numbness, but hyperalgesia and allodynia represent the most bothersome symptoms. The management of NP is a clinical challenge and several non-pharmacological and pharmacological interventions have been proposed with variable benefits. Botulinum toxin (BTX) as an adjunct to other interventions can be a useful therapeutic tool for the treatment of disabled people. Although BTX-A is predominantly used to reduce spasticity in a neuro-rehabilitation setting, it has been used in several painful conditions including disorders characterized by NP. The underlying pharmacological mechanisms that operate in reducing pain are still unclear and include blocking nociceptor transduction, the reduction of neurogenic inflammation by inhibiting neural substances and neurotransmitters, and the prevention of peripheral and central sensitization. Some neurological disorders requiring rehabilitative intervention can show neuropathic pain resistant to common analgesic treatment. This paper addresses the effect of BTX-A in treating NP that complicates frequent disorders of the central and peripheral nervous system such as spinal cord injury, post-stroke shoulder pain, and painful diabetic neuropathy, which are commonly managed in a rehabilitation setting. Furthermore, BTX-A has an effect in relief pain that may characterize less common neurological disorders including post-traumatic neuralgia, phantom limb, and complex regional pain syndrome with focal dystonia. The use of BTX-A could represent a novel therapeutic strategy in caring for neuropathic pain whenever common pharmacological tools have been ineffective. However, large and well-designed clinical trials are needed to recommend BTX-A use in the relief of neuropathic pain.

Pharmacological treatment of diabetic peripheral neuropathy

Pain modulation is a key treatment goal for diabetic peripheral neuropathy patients. Guidelines have recommended antidepressant, anticonvulsant, analgesic, and topical medications-both approved and off-label-to reduce pain in this population.

Pathways in the diagnosis and management of diabetic polyneuropathy

Distal symmetric polyneuropathy (DSPN), the most common form of diabetic neuropathy, has a complex pathophysiology and can be a major source of physical and psychologic disability. The management of DSPN can be frustrating for both patient and physician. This article provides a general overview of typical patient pathways in DSPN, and highlights variations in diagnosis, management, and referral patterns among different providers. DSPN is managed in several settings by primary care physicians (PCPs), specialists, and nurse practitioners. The initial clinical management of the patient is often dependent on the presenting complaint, the referral pattern of the provider, level of comfort of the PCP in managing diabetic complications, and geographic access to specialists. The primary treatment of DSPN focuses mainly on glycemic control and adjustment of modifiable risk factors, but other causes of neuropathy should also be investigated. Several pharmacologic agents are recommended by treatment guidelines, and as DSPN typically exists with comorbid conditions, a multimodal therapeutic approach should be considered. Barriers to effective management include failure to recognize DSPN, and misdiagnosis. Patient education also remains important. Referral patterns vary widely according to geographic location, access to services, provider preferences, and comfort in managing complex aspects of the disease. The variability in patient pathways affects patient education, satisfaction, and outcomes. Standardized screening tools, a multidisciplinary team approach, and treatment algorithms for diabetic neuropathy should improve future care. To improve patient outcomes, DSPN needs to be diagnosed sooner and interventions made before significant nerve damage occurs.