Longitudinal patient-oriented outcomes in neuropathy: Importance of early detection and falls

Obesity-related neuropathy: the new epidemic

PURPOSE OF REVIEW

To examine the evidence evaluating the association between obesity and neuropathy as well as potential interventions.

RECENT FINDINGS

Although diabetes has long been associated with neuropathy, additional metabolic syndrome components, including obesity, are increasingly linked to neuropathy development, regardless of glycemic status. Preclinical rodent models as well as clinical studies are shedding light on the mechanisms of obesity-related neuropathy as well as challenges associated with slowing progression. Dietary and surgical weight loss and exercise interventions are promising, but more data is needed.

SUMMARY

High-fat-diet rodent models have shown that obesity-related neuropathy is a product of excess glucose and lipid accumulation leading to inflammation and cell death. Clinical studies consistently demonstrate obesity is independently associated with neuropathy; therefore, likely a causal risk factor. Dietary weight loss improves neuropathy symptoms but not examination scores. Bariatric surgery and exercise are promising interventions, but larger, more rigorous studies are needed. Further research is also needed to determine the utility of weight loss medications and ideal timing for obesity interventions to prevent neuropathy.

Prevalence and Risk Factors of Distal Symmetric Polyneuropathy Among Predominantly Non-Hispanic Black, Low-Income Patients

BACKGROUND AND OBJECTIVES

Distal symmetric polyneuropathy (DSP) is a disabling, often painful condition associated with falls and reduced quality of life. Non-Hispanic Black people and people with low income are underrepresented in existing DSP studies; therefore, it is unknown whether data accurately reflect the prevalence, risk factors, and burden of disease in these populations.

METHODS

Patients older than 40 years presenting to an outpatient internal medicine clinic predominantly serving Medicaid patients in Flint, Michigan, were enrolled in a cross-sectional study. Demographics, clinical characteristics, including medication use, anthropomorphic measurements, fasting lipids, and hemoglobin A1c were collected. DSP was defined using the modified Toronto Clinical Neuropathy Score (mTCNS). Multivariable logistic regression was performed to model DSP and undiagnosed DSP as a function of potential risk factors age, metabolic syndrome, and race. DSP burden was measured using Peripheral Neuropathy Quality of Life Instrument-97.

RESULTS

Two hundred participants were enrolled, and 169 (85%) completed all data collection. The population was 55% female of mean age (SD) 58.2 years (10.4) and 69% non-Hispanic Black. Among the population, 50% had diabetes, 67% had metabolic syndrome, and 47% had a household income <$20,000. DSP was present in 73% of the population, of which 75% were previously undiagnosed. Neuropathic pain was documented in 57% of participants with DSP. DSP based on mTCNS criteria was associated with older age (odds ratio [OR] 1.1 [95% confidence interval (CI) 1.03-1.2]) and metabolic syndrome (OR 4.4 [1.1-18.1]). Non-Hispanic Black participants had lower odds of DSP (OR 0.1 [0.01-0.4]) than non-Hispanic White and Hispanic participants. DSP burden was high, including increased pain, health-related worry, and poorer quality of life (all p < 0.001).

DISCUSSION

DSP is extremely common and often underrecognized in this predominantly non-Hispanic Black, low-income population and leads to substantial disease burden. Metabolic syndrome is a highly prevalent, modifiable risk factor in this population that should be managed to lower DSP prevalence.

The effects of wearing textured versus smooth shoe insoles for 4-weeks in people with diabetic peripheral neuropathy: a randomised controlled trial

PURPOSE

To determine whether short-term wear of textured insoles alters balance, gait, foot sensation, physical activity, or patient-reported outcomes, in people with diabetic neuropathy.

MATERIALS AND METHODS

53 adults with diabetic neuropathy were randomised to wear textured or smooth insoles for 4-weeks. At baseline and post-intervention, balance (foam/firm surface; eyes open/closed) and walking were assessed whilst barefoot, wearing shoes only, and two insoles (textured/smooth). The primary outcome was center of pressure (CoP) total sway velocity. Secondary outcomes included other CoP measures, spatiotemporal gait measures, foot sensation, physical activity, and patient-reported outcomes (foot health, falls efficacy).

RESULTS

Wearing textured insoles led to improvements in CoP measures when standing on foam with eyes open, relative to smooth insoles (p ≤ 0.04). The intervention group demonstrated a 5% reduction in total sway velocity, indicative of greater balance. The intervention group also showed a 9-point improvement in self-perceived vigour (p = 0.03). Adjustments for multiple comparisons were not applied.

CONCLUSIONS

This study provides weak statistical evidence in favour of textured insoles. Wearing textured insoles may alter measures of balance, suggestive of greater stability, in people with diabetic neuropathy. Plantar stimulation, through textured insoles, may have the capacity to modulate the perception of foot pain, leading to improved well-being.IMPLICATIONS FOR REHABILITATIONShort-term wear of textured insoles can lead to improvements in centre of pressure sway measures when standing on a compliant supporting surface.Wearing textured insoles may have the capacity to help relieve foot pain leading to enhanced self-perceived vitality in people with diabetic peripheral neuropathy.

Dynapenic abdominal obesity and susceptibility to fall: a prospective analysis of the Osteoarthritis Initiative

Background

The prediction of the risk of falling remains a challenge in geriatric medicine and the identification of new potential reversible risk factors is a public health priority. In this study, we aim to investigate the association between DAO (dynapenic abdominal obesity) and incident falls in a large sample of people with knee OA (osteoarthritis) or at high risk for this condition, over 8 years of follow-up.

Methods

DAO was defined using a waist circumference more than 102 cm in men and 88 cm in women and a concomitant presence of dynapenia, defined as a time over 15 s in the five times chair stands time. Falls, during follow-up, were recorded using self-reported information in the previous year. A logistic binary regression analysis was run, adjusted for potential confounders at the baseline, reporting the data as odds ratios (ORs) with their 95% confidence intervals (CIs).

Results

Overall, 3,844 subjects were included, majority of whom had abdominal obesity. Across the 8 years of follow-up, 2,695 participants fell vs. 1,149 not reporting any fall. Taking those without DAO as reference, the presence of only dynapenia was not associated with risk of falls (OR = 1.18;95%CI: 0.73-1.91; p = 0.50), whilst the presence of abdominal obesity (OR = 1.30; 95%CI: 1.09-1.56; p = 0.004) and DAO (OR = 1.31; 95%CI:1.01-1.73; p = 0.04) were significantly associated with a higher risk of incident falls.

Conclusion

DAO significantly increased risk of falls as well as the presence of abdominal obesity.

Effect of strength training on functional outcomes and strength in patients with polyneuropathy: A scoping review

Introduction: Polyneuropathy (PNP) is a chronic progressive disease that over time can lead to damage of sensory, motor and/or autonomic peripheral nerves. Symptoms vary from predominantly sensory to severe sensorimotor affection both proximally and distally. This can result in considerable functional impairments that affect activities of daily living. In other neurological patients, strength training has shown to improve strength and functional outcomes. Since medical treatment only exists for very few percentages of the underlying causes it is obvious to consider if strength training could be a potential treatment for functional impairments. To date little is known on the effect of strength training in patients with PNP.

Aim: The aim of this scoping review was to summarize research on strength training and outcomes on physical function in patients with PNP.

Methods: We systematically searched five data bases; Pubmed, Embase, Cinahl, Cochrane library and Web of science. Studies on strength training (load ≥70% of 1RM) in patients with PNP were included. The search was carried out in November 2022.

Results: 362 articles were screened by title and abstract, 101 articles were full text screened. Eight studies were included. Patients with Charcot-Marie-Tooth (CMT), chronic inflammatory polyneuropathy (CIDP) and diabetic polyneuropathy (DPN) were represented in the studies (five RCTs, two case-series, and one cross-over trial). The methodological quality ranged from fair-poor in seven studies, one study reached good quality. Results from the studies indicated that strength training in CMT, CIDP and DPN may improve strength. However, various outcomes were used to evaluate strength training, so direct comparisons were difficult.

Discussion: In this scoping review we summarized research on strength training and outcomes evaluated in interventions in patients with PNP. Eight studies were included, they indicated that strength training may be beneficial for patients with PNP. However, due to low methodological strength of most studies a recommendation for patients with PNP cannot be made. Thus, the low number of studies with relatively low quality, where various functional outcomes were used, underscores the importance of future studies to evaluate the effect of strength training on relevant functional outcomes and strength in patients with PNP.

Diabetes Distal Peripheral Neuropathy: Subtypes and Diagnostic and Screening Technologies

Diabetes distal symmetrical peripheral neuropathy (DSPN) is the most prevalent form of neuropathy in industrialized countries, substantially increasing risk for morbidity and pre-mature mortality. DSPN may manifest with small-fiber disease, large-fiber disease, or a combination of both. This review summarizes: (1) DSPN subtypes (small- and large-fiber disease) with attention to clinical signs and patient symptoms; and (2) technological diagnosis and screening for large- and small-fiber disease with inclusion of a comprehensive literature review of published studies from 2015-present (N = 66). Review findings, informed by the most up-to-date research, advance critical understanding of DSPN large- and small-fiber screening technologies, including those designed for point-of-care use in primary care and endocrinology practices.

COVID-19 and the hidden threat of diabetic microvascular complications

The coronavirus disease 2019 (COVID-19) pandemic affected at least 200 million individuals worldwide and resulted in nearly 5 million deaths as of October 2021. According to the latest data from the International Diabetes Federation (IDF) in 2021, the diabetes pandemic has affected 537 million people and is associated with 6.7 million deaths. Given the high prevalence of both diabetes and COVID-19 and common pathological outcomes, a bidirectional relationship could have a catastrophic outcome. The increased risk of COVID-19 in those with obesity and diabetes and higher morbidity and mortality has received considerable attention. However, little attention has been given to the relationship between COVID-19 and microvascular complications. Indeed, microvascular complications are associated with an increased risk of cardiovascular disease (CVD) and mortality in diabetes. This review assesses the evidence for an association between diabetic microvascular complications (neuropathy, nephropathy, and retinopathy) and COVID-19. It draws parallels between the pathological changes occurring in the microvasculature in both diseases and assesses whether microvascular disease is a prognostic factor for COVID-19 outcomes in diabetes.

Physiological Changes and Pathological Pain Associated with Sedentary Lifestyle-Induced Body Systems Fat Accumulation and Their Modulation by Physical Exercise

A sedentary lifestyle is associated with overweight/obesity, which involves excessive fat body accumulation, triggering structural and functional changes in tissues, organs, and body systems. Research shows that this fat accumulation is responsible for several comorbidities, including cardiovascular, gastrointestinal, and metabolic dysfunctions, as well as pathological pain behaviors. These health concerns are related to the crosstalk between adipose tissue and body systems, leading to pathophysiological changes to the latter. To deal with these health issues, it has been suggested that physical exercise may reverse part of these obesity-related pathologies by modulating the cross talk between the adipose tissue and body systems. In this context, this review was carried out to provide knowledge about (i) the structural and functional changes in tissues, organs, and body systems from accumulation of fat in obesity, emphasizing the crosstalk between fat and body tissues; (ii) the crosstalk between fat and body tissues triggering pain; and (iii) the effects of physical exercise on body tissues and organs in obese and non-obese subjects, and their impact on pathological pain. This information may help one to better understand this crosstalk and the factors involved, and it could be useful in designing more specific training interventions (according to the nature of the comorbidity).

Dietary weight loss in people with severe obesity stabilizes neuropathy and improves symptomatology

OBJECTIVE

The aim of this study was to determine the effect of dietary weight loss on neuropathy outcomes in people with severe obesity.

METHODS

A prospective cohort study of participants attending a medical weight-management program was followed. Weight loss was achieved with meal replacement of 800 kcal/d for 12 weeks and then transitioning to 1,200 to 1,500 kcal/d. The coprimary outcomes were changes in intraepidermal nerve fiber density (IENFD) at the distal leg and proximal thigh. Secondary outcomes included nerve conduction studies, Michigan Neuropathy Screening Instrument questionnaire and exam, Quality of Life in Neurological Disorders, and quantitative sensory testing.

RESULTS

Among 131 baseline participants, 72 (mean [SD] age: 50.1 [10.5] years, 51.4% female) completed 2 years of follow-up. Participants lost 12.4 (11.8) kg. All metabolic syndrome components improved with the exception of blood pressure. IENFD in the distal leg (0.4 [3.3], p = 0.29), and proximal thigh (0.3 [6.3], p = 0.74) did not significantly change. Improvements were observed on the Michigan Neuropathy Screening Instrument questionnaire, two Quality of Life in Neurological Disorders subdomains, and quantitative sensory testing cold threshold.

CONCLUSIONS

Dietary weight loss was associated with improvements in all metabolic parameters except blood pressure, and both IENFD outcomes remained stable after 2 years. Given that natural history studies reveal decreases in IENFD over time, dietary weight loss may halt this progression, but randomized controlled trials are needed.

Extensor digitorum brevis bulk and associations with fibular motor nerve conduction amplitude

INTRODUCTION

Prior work demonstrates that fibular compound motor action potential (CMAP) amplitude <4.0 mV predicts impairment of ankle proprioceptive precision and increased fall risk. Extensor digitorum brevis (EDB) inspection may present a simple clinical surrogate for CMAP amplitude.

OBJECTIVE

(1) To estimate the inter-rater reliability of assessment of EDB bulk. (2) To determine whether inspection of EDB bulk is associated with fibular CMAP amplitude.

DESIGN

Prospective inter-raterreliability study.

SETTING

Academic center outpatient Physical Medicine & Rehabilitation electromyography (EMG) clinics.

PARTICIPANTS

Fifty-two adult participants (102 feet).

MAIN OUTCOME MEASURES

(1) Inter-rater reliability of assessment of EDB bulk. (2) Mean fibular CMAP amplitude. (3) A binary measure of fibular CMAP amplitude at/above or below a 4.0 mV threshold.

RESULTS

Inter-rater reliability of EDB bulk grading was moderate (kappa: 0.65 [95% confidence interval (CI) 0.48-0.82]). The mean CMAP value was 5.9 ± 2.2 mV when bulk was normal, 3.4 ± 2.1 mV when diminished, and 0.6 ± 0.9 mV when atrophied. A multivariable analysis demonstrated that EDB bulk, distal symmetric polyneuropathy (DSP), and lumbar radiculopathy were all associated with CMAP amplitude. The sensitivity and specificity of grading muscle bulk as normal versus abnormal in detecting CMAP amplitude above or below 4.0 mV were 0.86 (95% CI 0.78-0.94) and 0.71 (95% CI 0.54-0.88), respectively. An atrophied EDB was a highly specific indicator that CMAP amplitude was abnormal (<4.0 mV) in 100% of cases (8/8).

CONCLUSIONS

EDB bulk was associated with fibular CMAP amplitude. Atrophy was a highly specific indicator for CMAP amplitude below 4.0 mV. Evaluation of EDB bulk may represent a quick and easy clinical surrogate marker for CMAP amplitude and distal neuromuscular impairment.

The complex association between pain and neuropathy

BACKGROUND

Several studies of patients with polyneuropathy failed to show differences between patients with and without pain. In the current study, we aimed to explore the association between neuropathic symptoms, mainly pain, and polyneuropathy characteristics.

METHODS

A prospective cross-sectional study recruiting 151 patients with non-diabetic polyneuropathy was performed between November 2016 and May 2017. A total of 38 patients with chronic inflammatory demyelinating neuropathy were excluded. Patients underwent clinical, electrophysiological and functional assessments of their polyneuropathy. Polyneuropathy characteristics were compared depending on the presence and severity of neuropathic symptoms.

RESULTS

The presence and the severity of weakness were associated with a more severe neuropathy as measured by clinical, electrophysiological and functional assessments, while the presence of pain was associated with higher sural amplitudes, and the severity of pain showed a curvilinear association with neuropathy severity.

CONCLUSIONS

Our study shows a novel finding of a curvilinear association between pain and polyneuropathy severity.

Influence of opioid prescribing standards on health outcomes among patients with long-term opioid use: a longitudinal cohort study

Background:

The College of Physicians and Surgeons of British Columbia introduced opioid prescribing standards and guidelines in mid-2016 in British Columbia. We evaluated impacts of the standards and guidelines on health outcomes.

Methods:

We conducted a longitudinal study with repeated measures using administrative data from December 2013 to March 2017. The study included BC patients with long-term use of prescription opioids. Those with a history of long-term care, palliative care or cancer were excluded. Patients were followed for a 12-month prepolicy period and 10-month postpolicy period and compared with historical controls. We estimated changes in level (sudden changes) and monthly trend (gradual changes) of rates of opioid overdose hospital admission, and secondary outcomes of all-cause hospital admission, all-cause emergency department visits, opioid overdose mortality and all-cause mortality.

Results:

The study included 68 113 patients in the main cohort and 68 429 historical controls. We did not find significant changes to opioid overdose hospital admissions in level (adjusted rate ratio [RR] 0.83, 95% confidence interval [CI] 0.45–1.54) or in trend (adjusted RR 1.00, 95% CI 0.91–1.10). All-cause hospital admissions declined in level but may have increased in trend, suggesting that a temporary decrease in hospital admissions may have occurred. We found no significant changes in all-cause emergency department visits, opioid overdose mortality or all-cause mortality.

Interpretation:

Among patients with a history of long-term prescription opioid use, the regulatory prescribing standards and guidelines were not associated with changes in opioid overdose hospital admissions, all-cause emergency department visits, opioid overdose mortality or all-cause mortality, or with a sustained reduction in all-cause hospital admissions, over a 10-month period after they were introduced. Future research should investigate whether opioid prescribing standards or guidelines are associated with use of nonopioid analgesic medications or nonpharmacologic treatments.

The Slipping Slipper Sign: A Poor Man's Test for Severe Diabetic Peripheral Neuropathy

BACKGROUND

Neuropathic feet are at very high risk for infection and amputation. The slipping slipper sign (SSS) is elicited by a simple questionnaire test reported to detect the presence of severe diabetic peripheral neuropathy. This test can be administered by non-medical staff. In this study, subjects with and without the SSS were evaluated by nerve conduction studies (NCS) and ultrasound measurements of the right sural nerve diameters as well as with traditional scoring systems for peripheral and autonomic neuropathy.

OBJECTIVE

To demonstrate that the Slipping Slipper Sign can be used as an index of severe diabetic peripheral neuropathyMethod:This was a prospective cross sectional study in which 74 patients with diabetes (38 positive and 36 negative for SSS) underwent ultrasonography and NCS of the right sural nerve by an examiner blinded to SSS status. Findings were evaluated against demography, clinical history, anthropometry as well as traditional clinical and autonomic neuropathic scores.

RESULTS

Patients without the SSS [median (IQR) = 10.0 years (4.0-20.3)] had a significantly shorter duration of diabetes compared with those with the SSS [median (IQR) = 15.0 years (8.5-25.0)], p = 0.028. The frequencies of retinopathy (36.8% vs 2.8%, p <  0.05) and cerebrovascular accidents (18.4% vs 13.9 %, p <  0.05) were higher among those with SSS compared with those without. Differences in nerve conduction characteristics were markedly significant. The amplitude of the sural sensory nerve action potential (SNAP) was ([median (IQR)] 0 microvolts vs 4.0 microvolts (0.0-10.8) p <  0.002) between those with and without SSS, respectively whilst none of patients with SSS had a recordable SNAP vs 78% without a SSS. Similarly, maximal thickness of the right sural nerve at the ankle 3.0 mm (2.3-3.4) vs 3.5 mm (3.0-3.9), and leg 3.4 mm (2.7-3.8) vs 3.9 mm (3.3-4.2) was reduced, p <  0.01 in patients with the SSS compared with those with a negative SSS.

CONCLUSION

The SSS identifies feet with objective neurophysiological and imaging characteristics of severe neuropathy.

Association of Cardiovascular Risk Burden With Risk and Progression of Disability: Mediating Role of Cardiovascular Disease and Cognitive Decline

Background Cardiovascular risk burden has been linked to cardiovascular disease (CVD) and cognitive decline, but its association with disability is unclear. We aimed to examined the association of cardiovascular risk burden assessed by the Framingham general cardiovascular risk score (FGCRS) with the risk and progression of disability and estimated the extent to which CVD and cognitive decline mediate this association. Methods and Results A total of 1480 older adults with no disabilities (mean age=79.32±7.38 years) from the Rush Memory and Aging Project were followed for up to 21 years. FGCRS at baseline was calculated and categorized into tertiles. Disability was assessed annually with activities of daily living. The number of CVDs was calculated by summing up the CVD events. Global cognitive function was assessed annually with a battery of 19 tests. Data were analyzed using the Cox model, linear mixed effects model, and mediation analysis. At the end of the follow-up, 713 (48.2%) participants developed disability. Compared with the lowest tertile of the FGCRS, the multiadjusted hazards ratios of disability were 1.34 (95% CI, 1.11-1.62) for the highest tertile. In addition, the highest FGCRS was associated with a change in activities of daily living score over time (β=0.057; 95% CI, 0.021-0.093). The association between FGCRS and change in activities of daily living was 13.8% mediated by the accumulation of CVDs and 25.1% by cognitive decline, respectively. Conclusions Higher cardiovascular risk burden increased the risk of disability and accelerated its progression over time. CVD accumulation and cognitive decline may partially mediate the association.

Central Obesity is Associated With Neuropathy in the Severely Obese

OBJECTIVE

To determine the prevalence of neuropathy stratified by glycemic status and the association between extensive anthropometric measurements and neuropathy.

PATIENTS AND METHODS

We performed a cross-sectional, observational study in obese individuals, before surgery, with body mass index (BMI) greater than 35 kg/m². Lean controls were recruited from a research website. Neuropathy was defined by the Toronto consensus definition of probable neuropathy. We compared nine anthropometric measurements between obese participants with and without neuropathy. We used multivariable logistic regression to explore associations between these measures, and other metabolic risk factors, and neuropathy.

RESULTS

We recruited 138 obese individuals and 46 lean controls. The mean age (SD) was 45.1 (11.3) years in the obese population (76.1% female, n=105) and 43.8 (12.1) years in the lean controls (82.2% female, n=37). The prevalence of neuropathy was 2.2% (n=1) in lean controls, 12.1% (n=4) in obese participants with normoglycemia, 7.1% (n=4) in obese participants with pre-diabetes, and 40.8% (n=20) in obese participants with diabetes (p≤.01). Waist circumference was the only anthropometric measure that was larger in those with neuropathy (139.3 cm vs 129.1 cm, p=.01). Hip-thigh (71.1 cm vs 76.6 cm, p<.01) and mid-thigh (62.2 cm vs 66.3 cm, p=.03) circumferences were smaller in those with neuropathy. The body mass index was comparable between patients who were obese with and without neuropathy (p=.86). Waist circumference (odds ratio [OR], 1.39; 95% CI, 1.10 to 1.75), systolic blood pressure (OR, 2.89; 95% CI, 1.49 to 5.61), and triglycerides (OR, 1.31; 95% CI, 1.00 to 1.70) were significantly associated with neuropathy.

CONCLUSION

Normoglycemic obese patients have a high prevalence of neuropathy indicating that obesity alone may be sufficient to cause neuropathy. Waist circumference, but not general obesity, is significantly associated with neuropathy.

Vibrotactile perception on the sole of the foot in an older group of people with normal glucose tolerance and type 2 diabetes

OBJECTIVES

To evaluate vibrotactile sense in an older group of people with normal glucose tolerance and type 2 diabetes relative to other sensory tests.

METHODS

Vibration perception thresholds on the sole of the foot (Multifrequency vibrametry and Biothesiometer) were compared to the results from evaluation of touch (monofilament), electrophysiology (sural nerve) and thermal sensation (Thermotest®).

RESULTS

Vibration perception and temperature thresholds, as well as sural nerve function, differed between normal glucose tolerance and type 2 diabetes. Measuring vibration perception thresholds at lower frequencies with multifrequency vibrametry versus biothesiometer provided correlations similar to sural nerve amplitude. Temperature thresholds correlated with vibration perception thresholds and sural nerve function. Monofilaments revealed pathology in only a few participants with type 2 diabetes.

CONCLUSIONS

In an older group of people, vibration perception thresholds show a correlation similar to sural nerve amplitude on tactile and non-tactile surfaces. Measuring a vibration perception threshold on a tactile surface in type 2 diabetes provides no clear advantage over measuring it on the medial malleolus. In older type 2 diabetes subjects, both large and small diameter nerve fibers are affected.

Polyneuropathie im Alter

Das periphere Nervensystem ist im Laufe des Alternsprozesses Veränderungen unterworfen. So kommt es unter anderem zu einer Abschwächung von Muskeleigenreflexen und Propriozeption. Davon abzugrenzen sind Polyneuropathien als krankhafte Veränderungen des peripheren Nervensystems. Die jährliche Inzidenz von Polyneuropathien wird auf 118/100.000 geschätzt, die Prävalenz liegt bei etwa 1 %, für ältere Populationen werden 7 % angegeben. Die Ursachen sind vielfältig und ähnlich den Ursachen von Neuropathien des jüngeren Alters: Neben metabolischen, immunvermittelten, hereditären, toxischen und infektiösen Ätiologien können Polyneuropathien Ausdruck von Systemerkrankungen sein. Entsprechend der Altersverteilung der verschiedenen Ursachen sind Neuropathien im Zusammenhang mit Diabetes, monoklonalen Gammopathien und Malignomen im Alter häufiger. Allerdings nimmt der Anteil der kryptogenen Neuropathien, also ohne eindeutige Ursache, mit dem Alter zu. Bei alten Menschen führen Polyneuropathien zu einer zusätzlichen Beeinträchtigung der Mobilität und einem erhöhten Sturzrisiko, was auch die Abklärung funktioneller Fähigkeiten erforderlich macht.

The Multidimensional Prognostic Index Predicts Falls in Older People: An 8-Year Longitudinal Cohort Study of the Osteoarthritis Initiative

OBJECTIVES

Falls are associated with several negative outcomes. Early identification of those who are at risk of falling is of importance in geriatrics, and comprehensive geriatric assessment (CGA) seems to be promising in this regard. Therefore, the present study investigated whether the multidimensional prognostic index (MPI), based on a standard CGA, is associated with falls in the Osteoarthritis Initiative (OAI).

DESIGN

Longitudinal, 8 years of follow-up.

SETTING AND PARTICIPANTS

Community-dwelling older people (≥65 years of age) with knee osteoarthritis or at high risk for this condition.

METHODS

A standardized CGA including information on functional, nutritional, mood, comorbidities, medications, quality of life, and cohabitation status was used to calculate a modified version of the MPI, categorized as MPI-1 (low), MPI-2 (moderate), and MPI-3 (high risk). Falls were self-reported and recurrent fallers were defined as ≥2 in the previous year. Logistic regression was carried out and results are reported as odds ratio (ORs) with their 95% confidence intervals (CIs).

RESULTS

The final sample consisted of 885 older adults (mean age 71.3 years, female = 54.6%). Recurrent fallers showed a significant higher MPI than their counterparts (0.46 ± 0.17 vs 0.38 ± 0.16; P < .001). Compared with those in MPI-1 category, participants in MPI-2 (OR 2.13; 95% CI 1.53‒2.94; P < .001) and in MPI-3 (OR 5.98; 95% CI 3.29-10.86; P < .001) reported a significant higher risk of recurrent falls over the 8-years of follow-up. Similar results were evident when using an increase in 0.1 points in the MPI or risk of falls after 1 year.

CONCLUSIONS AND IMPLICATIONS

Higher MPI values at baseline were associated with an increased risk of recurrent falls, suggesting the importance of CGA in predicting falls in older people.

Influence of opioid prescribing standards on drug use among patients with long-term opioid use: a longitudinal cohort study

BACKGROUND

In mid-2016, the College of Physicians and Surgeons of British Columbia (CPSBC) issued prescribing standards and guidelines relating to opioid drugs. We evaluated the impact of these regulatory standards and guidelines on prescription drug use among patients in the province with long-term opioid use.

METHODS

We conducted a cohort study with monthly repeated measures using administrative health data in British Columbia. Patients with long-term prescription opioid use were followed for a 12-month prepolicy period and 10-month postpolicy period, and were compared with a historical control cohort. We excluded patients with a history of long-term care, palliative care or cancer. We estimated changes in use of opioids, high-dose opioids (> 90 mg of morphine equivalents/d), opioids with sedatives/hypnotics, and opioid discontinuation.

RESULTS

The study population included 68 113 patients in the policy cohort and 68 429 patients in the historical control cohort. Following the introduction of the standards and guidelines, the average monthly use of opioids declined (adjusted difference -57 mg of morphine equivalents, 95% confidence interval [CI] -74 to -39) and discontinuation of opioids increased (odds ratio [OR] 1.24, 95% CI 1.16 to 1.32). Among patients prescribed high-dose opioids, switching to lower-dose opioids increased (OR 1.88, 95% CI 1.63 to 2.17), but discontinuation did not change significantly (OR 1.21, 95% CI 0.91 to 1.59).

INTERPRETATION

The CPSBC's regulatory standards and guidelines were associated with modestly reduced opioid use and increased switching from high-dose to lower-dose opioids among patients with long-term use of prescribed opioids. Assessment of the potential impacts on health outcomes will be necessary for understanding the implications of the standards and guidelines.

Diabetic neuropathy

The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.

Diabetic neuropathy

The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.

Geriatric Polypharmacy: Pharmacist as Key Facilitator in Assessing for Falls Risk: 2019 Update

This article highlights the significant health impact of falls among older adults. An emphasis is placed on the vital role of the pharmacist, regardless of practice setting, in assessing and reducing falls risk for this growing population. In addition, the importance of a stepwise comprehensive approach to falls assessment by pharmacists in collaboration with other clinicians is elucidated.

The pace and prognosis of peripheral sensory loss in advanced age: association with gait speed and falls

Background

Peripheral sensory loss is considered one of many risk factors for gait impairments and falls in older adults, yet no prospective studies have examined changes in touch sensation in the foot over time and their relationship to mobility and falls. Therefore, we aimed to determine the prevalence and progression of peripheral sensory deficits in the feet of older adults, and whether sensory changes are associated with the slowing of gait and development of falls over 5 years.

Methods

Using baseline, and 18 and 60 month followup data from the Maintenance Of Balance, Independent Living, Intellect, and Zest in the Elderly (MOBILIZE) Study in Boston, MA, we determined changes in the ability to detect stimulation of the great toe with Semmes Weinstein monofilaments in 351 older adults. We used covariate-adjusted repeated measures analysis of variance to determine relationships between sensory changes and gait speed or fall rates.

Results

Subjects whose sensory function was consistently impaired over 5 years had a significantly steeper decline in gait speed (− 0.23 m/s; 95% CI: -0.28 to − 0.18) compared to those with consistently intact sensory function (− 0.12 m/s; 95% CI: -0.15 to − 0.08) and those progressing from intact to impaired sensory function (− 0.13 m/s; − 0.16 to − 0.10). Compared to subjects with consistently intact sensation, those whose sensory function progressed to impairment during followup had the greatest risk of falls (adjusted risk ratio = 1.57 (95% confidence interval = 1.12 to 2.22).

Conclusions

Our longitudinal results indicate that a progressive decline in peripheral touch sensation is a risk factor for mobility impairment and falls in older adults.

Value-Added Electrodiagnostics: Targeting Interventions for Fall Risk Reduction

Walking confers numerous health benefits, particularly for middle-aged and older patients with diabetes and metabolic syndrome. Nevertheless, it brings a risk of injurious falls, especially among populations with diabetes and metabolic syndrome-related distal neuromuscular decline and frank neuropathy. Those who stand to benefit most from walking are at greatest risk. Development of practical clinical tools to more precisely quantify neuromuscular function and link it to mobility outcomes will help clinicians target interventions toward those at risk for falls. Electrodiagnosis, with inclusion of several newer techniques, serves as a promising tool for objective evaluation of distal neuromuscular function.

General Approach to Peripheral Nerve Disorders

PURPOSE OF REVIEW

This article provides a conceptual framework for the evaluation of patients with suspected polyneuropathy to enhance the clinician's ability to localize and confirm peripheral nervous system pathology and, when possible, identify an etiologic diagnosis through use of rational clinical and judicious testing strategies.

RECENT FINDINGS

Although these strategies are largely time-honored, recent insights pertaining to the pathophysiology of certain immune-mediated neuropathies and to evolving genetic testing strategies may modify the way that select causes of neuropathy are conceptualized, evaluated, and managed.

SUMMARY

The strategies suggested in this article are intended to facilitate accurate bedside diagnosis in patients with suspected polyneuropathy and allow efficient and judicious use of supplementary testing and application of rational treatment when indicated.

Cytokine-mediated inflammation mediates painful neuropathy from metabolic syndrome

Painful neuropathy (PN) is a prevalent condition in patients with metabolic syndrome (MetS). However, the pathogenic mechanisms of metabolic syndrome-associated painful neuropathy (MetSPN) remain unclear. In the current study, high-fat-fed mice (HF mice) were used to study MetSPN. HF mice developed MetS phenotypes, including increased body weight, elevated plasma cholesterol levels, and insulin resistance in comparison with control-fat-fed (CF) mice. Subsequently, HF mice developed mechanical allodynia and thermal hyperalgesia in hind paws after 8 wk of diet treatment. These pain behaviors coincided with increased densities of nociceptive epidermal nerve fibers and inflammatory cells such as Langerhans cells and macrophages in hind paw skin. To study the effect of MetS on profiles of cytokine expression in HF mice, we used a multiplex cytokine assay to study the protein expression of 12 pro-inflammatory and anti-inflammatory cytokines in dorsal root ganglion and serum samples. This method detected the elevated levels of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, and interleukin (IL)-6, IL-1β as well as reduced anti-inflammatory IL-10 in lumbar dorsal root ganglia (LDRG) of HF mice. Intraperitoneal administration of IL-10 reduced the upregulation of pro-inflammatory cytokines and alleviated pain behaviors in HF mice without affecting MetS phenotypes. Our findings suggested targeting HF-induced cytokine dysregulation could be an effective strategy for treating MetSPN.

Single Sensor Gait Analysis to Detect Diabetic Peripheral Neuropathy: A Proof of Principle Study

This study explored the potential utility of gait analysis using a single sensor unit (inertial measurement unit [IMU]) as a simple tool to detect peripheral neuropathy in people with diabetes. Seventeen people (14 men) aged 63±9 years (mean±SD) with diabetic peripheral neuropathy performed a 10-m walk test instrumented with an IMU on the lower back. Compared to a reference healthy control data set (matched by gender, age, and body mass index) both spatiotemporal and gait control variables were different between groups, with walking speed, step time, and SDa (gait control parameter) demonstrating good discriminatory power (receiver operating characteristic area under the curve >0.8). These results provide a proof of principle of this relatively simple approach which, when applied in clinical practice, can detect a signal from those with known diabetes peripheral neuropathy. The technology has the potential to be used both routinely in the clinic and for tele-health applications. Further research should focus on investigating its efficacy as an early indicator of or effectiveness of the management of peripheral neuropathy. This could support the development of interventions to prevent complications such as foot ulceration or Charcot's foot.

Sciatic neurosteatosis: Relationship with age, gender, obesity and height

AIM

To evaluate inter-reader performance for cross-sectional area and fat quantification of bilateral sciatic nerves on MRI and assess correlations with anthropometrics.

METHODS

In this IRB-approved, HIPPA-compliant study, three readers performed a cross-sectional analysis of 3T lumbosacral plexus MRIs over an 18-month period. Image slices were evaluated at two levels (A and B). The sciatic nerve was outlined using a free hand region of interest tool on PACS. Proton-density fat fraction (FF) and cross-sectional areas were recorded. Inter-reader agreement was assessed using intra-class correlation coefficient (ICC). Spearman correlation coefficients were used for correlations with age, BMI and height and Wilcoxon rank sum test was used to assess gender differences.

RESULTS

A total of 67 patients were included in this study with male to female ratio of 1:1. Inter-reader agreement was good to excellent for FF measurements at both levels (ICC=0.71-0.90) and poor for sciatic nerve areas (ICC=0.08-0.27). Positive correlations of sciatic FF and area were seen with age (p value<0.05). Males had significantly higher sciatic intraneural fat than females (p<0.05).

CONCLUSION

Fat quantification MRI is highly reproducible with significant positive correlations of sciatic FF and area with age, which may have implications for MRI diagnosis of sciatic neuropathy.

KEY POINTS

• MR proton density fat fraction is highly reproducible at multiple levels. • Sciatic intraneural fat is positively correlated with increasing age (p < 0.05). • Positive correlations exist between bilateral sciatic nerve areas and age (p < 0.05). • Males had significantly higher sciatic intraneural fat than females (p < 0.05).

Polyneuropathy relates to impairment in daily activities, worse gait, and fall-related injuries

OBJECTIVE

To extensively investigate the association of chronic polyneuropathy with basic and instrumental activities of daily living (BADL and IADL), falls, and gait.

METHODS

A total of 1,445 participants of the population-based Rotterdam Study (mean age 71 years, 54% women) underwent a polyneuropathy screening involving a symptom questionnaire, neurologic examination, and nerve conduction studies. Screening yielded 4 groups: no, possible, probable, and definite polyneuropathy. Participants were interviewed about BADL (Stanford Health Assessment questionnaire), IADL (Instrumental Activities of Daily Living scale), and frequency of falling in the previous year. In a random subset of 977 participants, gait was assessed with an electronic walkway. Associations of polyneuropathy with BADL and IADL were analyzed continuously with linear regression and dichotomously with logistic regression. History of falling was evaluated with logistic regression, and gait changes were evaluated with linear regression.

RESULTS

Participants with definite polyneuropathy had more difficulty in performing BADL and IADL than participants without polyneuropathy. Polyneuropathy related to worse scores of all BADL components (especially walking) and 3 IADL components (housekeeping, traveling, and shopping). Participants with definite polyneuropathy were more likely to fall, and these falls more often resulted in injury. Participants with polyneuropathy had worse gait parameters on the walkway, including lower walking speed and cadence, and more errors in tandem walking.

CONCLUSIONS

Chronic polyneuropathy strongly associates with impairment in the ability to perform daily activities and relates to worse gait and an increased history of falling.

[Polyneuropathy in the elderly]

The peripheral nervous system is subject to changes during the ageing process, e. g. deep tendon reflexes decrease, as does proprioception. Polyneuropathies, on the other hand, need to be distinguished from age-related changes as independent diseases with etiologies similar to those at younger ages. Etiologies includes metabolic disorders, primary inflammatory polyneuropathies, and systemic disorders. Neuropathies associated with diabetes, malignancy, and monoclonal gammopathies appear to be more common in older patients. Using a systematic approach, it is possible to establish a specific diagnosis in the majority of cases. Since polyneuropathies contribute to reduced mobility in the elderly, an assessment of functional skills is mandatory. Polyneuropathy therapy is primarily based on the treatment of underlying conditions and neuropathic pain management. Physiotherapy and rehabilitation target pain relief and maintaining activities of daily living.

Geriatric Polypharmacy: Pharmacist as Key Facilitator in Assessing for Falls Risk

This article highlights the significant health impact of falls among older adults. An emphasis is placed on the vital role of the pharmacist, regardless of practice setting, in assessing and reducing falls risk for this growing population. In addition, the importance of a stepwise comprehensive approach to falls assessment by pharmacists in collaboration with other clinicians is elucidated.

Mediators of diabetic neuropathy: is hyperglycemia the only culprit?

PURPOSE OF REVIEW

Diabetic peripheral neuropathy (DPN) is a disabling, highly prevalent complication of both type 1 and type 2 diabetes mellitus (T1DM and T2DM). Large clinical studies support the concept that, in addition to hyperglycemia, components of the metabolic syndrome (MetS) may underlie the pathogenesis of DPN, especially in T2DM. This review will present the evidence supporting the MetS and its individual components as potential causal factors for the development of neuropathy.

RECENT FINDINGS

In addition to poor glycemic control and duration of diabetes, components of MetS such as dyslipidemia, obesity, and hypertension may have an important impact on the prevalence of DPN. Obesity and prediabetes have the most data to support their role in neuropathy, whereas hypertension and dyslipidemia have more mixed results. Nonmetabolic factors, such as genetic susceptibility, age, height, sex, smoking, and alcohol, have also been highlighted as potential risk factors in peripheral neuropathy, although the exact contribution of these factors to DPN remains unknown.

SUMMARY

DPN is a chronic and disabling disease, and the accurate identification and modification of DPN risk factors is important for clinical management. Recent data support a role for components of the MetS and other risk factors in the development of DPN, offering novel targets beyond hyperglycemia for therapeutic development.

Metabolic Syndrome Components Are Associated With Symptomatic Polyneuropathy Independent of Glycemic Status

OBJECTIVE

Previous studies demonstrate that the metabolic syndrome is associated with distal symmetric polyneuropathy (DSP). We aimed to determine the magnitude of this effect and the precise components involved.

RESEARCH DESIGN AND METHODS

We determined the symptomatic DSP prevalence in the Health, Aging, and Body Composition (Health ABC) study (prospective cohort study, with subjects aged 70-79 years at baseline), stratified by glycemic status (glucose tolerance test) and the number of additional metabolic syndrome components (updated National Cholesterol Education Program/Adult Treatment Panel III definition). DSP was defined as neuropathic symptoms (questionnaire) plus at least one of three confirmatory tests (heavy monofilament, peroneal conduction velocity, and vibration threshold). Multivariable logistic and linear regression evaluated the association of metabolic syndrome components with DSP in cross-sectional and longitudinal analyses.

RESULTS

Of 2,382 participants with neuropathy measures (mean age 73.5 ± 2.9 years, 38.2% black, 51.7% women), 21.0% had diabetes, 29.9% prediabetes, 52.8% metabolic syndrome, and 11.1% DSP. Stratified by glycemic status, DSP prevalence increased as the number of metabolic syndrome components increased (P = 0.03). Diabetes (cross-sectional model, odds ratio [OR] 1.65 [95% CI 1.18-2.31]) and baseline hemoglobin A1C (longitudinal model, OR 1.42 [95% CI 1.15-1.75]) were the only metabolic syndrome measures significantly associated with DSP. Waist circumference and HDL were significantly associated with multiple secondary neuropathy outcomes.

CONCLUSIONS

Independent of glycemic status, symptomatic DSP is more common in those with additional metabolic syndrome components. However, the issue of which metabolic syndrome components drive this association, in addition to hyperglycemia, remains unclear. Larger waist circumference and low HDL may be associated with DSP, but larger studies with more precise metabolic measures are needed.

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.

Mobility-Related Consequences of Reduced Lower-Extremity Peripheral Nerve Function with Age: A Systematic Review

The objective of this study is to systematically review the relationship between lower-extremity peripheral nerve function and mobility in older adults. The National Library of Medicine (PubMed) was searched on March 23, 2015 with no limits on publication dates. One reviewer selected original research studies of older adults (≥65 years) that assessed the relationship between lower-extremity peripheral nerve function and mobility-related outcomes. Participants, study design and methods of assessing peripheral nerve impairment were evaluated and results were reported and synthesized. Eight articles were identified, including 6 cross-sectional and 2 longitudinal studies. These articles investigated 6 elderly cohorts (4 from the U.S. and 2 from Italy): 3 community-dwelling (including 1 with only disabled women and 1 without mobility limitations at baseline), 1 with both community-dwelling and institutionalized residents, 1 from a range of residential locations, and 1 of patients with peripheral arterial disease. Mean ages ranged from 71-82 years. Nerve function was assessed by vibration threshold (n=2); sensory measures and clinical signs and symptoms of neuropathy (n=2); motor nerve conduction (n=1); and a combination of both sensory measures and motor nerve conduction (n=3). Each study found that worse peripheral nerve function was related to poor mobility, although relationships varied based on the nerve function measure and mobility domain assessed. Six studies found that the association between nerve function and mobility persisted despite adjustment for diabetes. Evidence suggests that peripheral nerve function impairment at various levels of severity is related to poor mobility independent of diabetes. Relationships varied depending on peripheral nerve measure, which may be particularly important when investigating specific biological mechanisms. Future research needs to identify risk factors for peripheral nerve decline beyond diabetes, especially those common in late-life and modifiable. Interventions to preserve nerve function should be investigated with regard to their effect on postponing or preventing disability in older adults.