Polyneuropathy is inadequately treated despite increasing symptom intensity in individuals with and without diabetes (PROTECT follow-up study)

Diagnostic performance of graded tuning fork vibration thresholds as a stand-alone test and within clinical assessments of diabetic neuropathy

AIMS

We aimed to provide new reference data for C64 Hz-Rydel-Seiffer tuning fork Vibration Sensation Thresholds (VST) for the clinical diagnosis of Diabetic Sensorimotor Polyneuropathy (DSPN) and to evaluate the diagnostic performance when used in combination with other clinical tests as implemented in the Neuropathy Disability Score (NDS).

METHODS

The study included 1,215 individuals with type 1 or type 2 diabetes and 207 with Normal Glucose Tolerance (NGT), who underwent clinical, electrophysiological, and Quantitative Sensory Tests (QST). Multiple regression analyses were used to determine VST in individuals with NGT. The diagnostic performance of tests to detect confirmed small or large fibre DSPN according to Toronto consensus criteria was assessed in 373 individuals with diabetes who underwent skin biopsies do determine intraepidermal nerve fibre density (IENFD).

RESULTS

The new age-dependent lower normative VST showed 73.5% sensitivity, 85.4% specificity, and 82.3% accuracy in diagnosing confirmed DSPN. Combining VST with the PinPrick test resulted in 83.4% sensitivity, 80.3% specificity, and 81.2% accuracy. The NDS incorporating VST was associated with nerve conduction indices, QST, and IENFD.

CONCLUSIONS

The new VST reference data shall enable clinicians to detect DSPN with higher accuracy in clinical practice, particularly when combined with a single small fibre test.

Fast Analgesic Effect in Response Test with Topical Phenytoin Cream Correlates with Prolonged Pain Relief After Extended Use in Painful Diabetic Neuropathy

Background: Treatment of painful diabetic neuropathy (PDN) poses several challenges due to the limited effectiveness, high incidence of side effects, and potential drug interactions of oral neuropathic pain medication. Lacking systemic side effects, topical phenytoin cream offers a promising innovative approach to addressing unmet needs in neuropathic pain treatment. In this retrospective study in patients with PDN, we evaluated the analgesic effect of topical phenytoin cream in response tests and after extended use. Methods: We collected data from PDN patients who, prior to prolonged use of phenytoin 10% or 20% cream, either had an open response test (ORET), a single-blind (SIBRET), or a double-blind (DOBRET) placebo-controlled response test with phenytoin cream between November 2016 and February 2023. A positive ORET was defined as pain reduction of at least two points on the 11-point numerical scale (NRS) within 30 min after phenytoin cream application. A positive SIBRET or DOBRET required an additional pain reduction of 1 NRS point in the phenytoin treated area compared to the placebo. In patients with a positive response test, we evaluated the sustained pain reduction and the proportion of patients experiencing minimum pain relief of at least 30% (MPR30: moderate pain relief) and 50% (MPR50: considerable pain relief) after the extended use of phenytoin cream. We also assessed the correlation between the response test analgesic effect and the sustained pain relief. Results: We identified 65 patients with PDN of whom 31 (47.7%) had a positive response test. The median pain reduction in response tests was 3.0 NRS points (IQR 2.0-4.0). Extended use (median 3.3 months, IQR 1.5-12.1]) resulted in a median pain reduction of 4.0 NRS points (IQR 3.0-5.0); 26/31 (83.9%) of patients achieved MPR30, and 21/31 (67.7%) MPR50 achieved pain relief. The response test analgesic effect correlated significantly with sustained pain relief after extended use (τ = 0.72, p < 0.0001). Conclusions: In PDN patients who had a positive phenytoin cream response test, extended use of phenytoin cream provided a significant sustained pain relief.

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

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

Current Practice of Podiatrists in Testing for Diabetic Polyneuropathy and Implementing Foot Care (PROTECT Study Survey 2)

AIMS

Podiatrists constitute a key member of a multidisciplinary foot care team, but their services remain underutilized. We sought to gain insights into the daily practice of podiatrists focusing on screening for and monitoring of diabetic sensorimotor polyneuropathy (DSPN) as well as foot management.

METHODS

This cross-sectional survey included 125 podiatrists from 12 federal states across Germany who responded to an online questionnaire.

RESULTS

The majority of patients treated in podiatry practices were referred by general practitioners and diabetologists. Screening for or follow-up of DSPN was performed by 36% of the respondents at least once a year, by 28% only at initial examination, by 21% only at suspicion, and by 10% basically at each treatment visit. Instruments to assess vibration, touch/pressure, and temperature sensation were used by 81% to 94% of the podiatrists. Previously undiagnosed DSPN and foot ulcers were detected frequently/very frequently (≥6 cases/mo) by 24.0 and 18.4% of the podiatrists, respectively. Almost all podiatrists advised daily self-monitoring of feet and appropriate foot care and >50% gave advice on medical treatment.

CONCLUSIONS

Podiatrists play an important role in the detection, monitoring, and management of both DSPN and diabetic foot ulcers, suggesting that the utilization of their services should be fostered.

Multimodal Approaches in the Treatment of Chronic Peripheral Neuropathy-Evidence from Germany

Patients with chronic peripheral neuropathy suffer greatly and their quality of life is often restricted. Drug therapy can be accompanied by undesirable side effects and intolerances, or the hoped-for effect does not materialize. Therefore, in addition to drug therapy, attempts are also made to treat the physical symptoms with complementary procedures. In the case of severe forms, the search for a suitable form of therapy is difficult. Complex treatments can be an innovative way to treat peripheral neuropathy. At the same time, several different therapy methods are carried out at high frequency by a specialized treatment team. This study aimed to provide an overview of possible complementary forms of therapy. The focus was on a comparison of two interdisciplinary complex therapies that are used in severe cases in an acute inpatient care setting in Germany. The six dimensions (energy, sleep, pain, physicality, emotional response and social isolation) of the Nottingham Health Profile (NHP) were used to assess quality of life. Both complex treatments (naturopathic complex therapy/multimodal pain therapy) showed a significant reduction in impairment in all dimensions of the NHP. In addition, a multivariate analysis was carried out to take into account several influencing variables at the same time. At the time of admission to the hospital, the degree of chronicity was recorded for each patient. This allowed statements to be made about the effect of the respective therapy depending on the chronification stage of the patient. It has been shown that patients with acutely exacerbated pain with the highest degree of chronicity also benefit from both complex treatments. The naturopathic complex treatment gives the treatment team more options. Aspects such as nutrition, methods from phytotherapy and traditional Chinese medicine can be integrated into inpatient care. Thus, a patient-centered, holistic therapy can take place. However, an interdisciplinary holistic therapy requires more time for both the practitioner and the patient. This should be taken into account in the health systems in the context of the diagnosis related groups.

Functional nucleic acids for the treatment of diabetic complications

In recent decades, diabetes mellitus (DM) has become a major global health problem owing to its high prevalence and increased incidence of diabetes-associated complications, including diabetic wounds (DWs), diabetic nephropathy, metabolic syndrome, diabetic retinopathy, and diabetic neuropathy. In both type 1 and type 2 diabetes, tissue damage is organ-specific, but closely related to the overproduction of reactive oxygen species (ROS) and hyperglycaemia-induced macrovascular system damage. However, existing therapies have limited effects on complete healing of diabetic complications. Fortunately, recent advances in functional nucleic acid materials have provided new opportunities for the treatment and diagnosis of diabetic complications. Functional nucleic acids possess independent structural functions that can replace traditional proteases and antibodies and perform specific biological non-genetic functions. This review summarises the current functional nucleic acid materials reported for the treatment of diabetic complications, including tetrahedral framework nucleic acids (tFNAs), short interfering RNA (siRNA), micorRNA (miRNA), locked nucleic acids, antisense oligonucleotides (ASOs), and DNA origami, which may assist in the development of novel nucleic acids with new functions and capabilities for better healing of diabetic complications.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Bacterial Diversity, Antibiotic Resistance, and the Risk of Lower Limb Amputation in Younger and Older Individuals With Diabetic Foot Infection

INTRODUCTION

A diabetic foot infection (DFI) contributes to high mortality and morbidity in diabetics due to its often rapid progressive and intricately treatable infection. DFIs are usually a polymicrobial infection and characterizing the entire bacterial load is still challenging. Prompt and effective treatment of DFI is nevertheless mandatory to safe limbs and lives. It is therefore crucial to know the local pathogen spectrum and its antibiotic susceptibility.

METHODS AND MATERIAL

For a 12-month period, we investigated 353 individuals with infected diabetic foot ulcer, their bacterial diversity, and antimicrobial susceptibility at fist-time visit in a Diabetic Foot Care Center in southern Germany.

RESULTS

Cultures yielded 888 species, most of them gram-positive cocci (primary Staphylococcus aureus). The gram-negative sector was mainly formed by Pseudomonas aeruginosa and Enterobacteriacae. Because the prevalence of multiresistant species was surprisingly low (0.9% of isolated strains), we suggest penicillins with β-lactamase inhibitor in case of gram-positive-dominated infection or piperacillin/tazobactam or rather carbapenems with equal efficacy when gram-negative species are involved.

Nerve conduction velocity is independently associated with bone mineral density in type 2 diabetes mellitus

AIM

This study investigated the association between nerve conduction velocity (NCV) and bone mineral density (BMD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study retrospectively collected medical data of T2DM patients who underwent dual-energy X-ray absorptiometry and nerve conduction study at the Shanghai Ruijin Hospital, Shanghai, China. The primary outcome was the total hip BMD T-score. The main independent variables were motor nerve conduction velocities (MCVs), sensory nerve conduction velocities (SCVs), and composite Z-scores of MCV and SCV. T2DM patients were divided into total hip BMD T-scores < -1 and total hip BMD T-scores ≥ -1 groups. The association between the primary outcome and main independent variables was evaluated by Pearson bivariate correlation and multivariate linear regression.

RESULTS

195 female and 415 male patients with T2DM were identified. In male patients with T2DM, bilateral ulnar, median, and tibial MCVs and bilateral sural SCVs were lower in the total hip BMD T-score < -1 group than T-score ≥ -1 group (P < 0.05). Bilateral ulnar, median, and tibial MCVs, and bilateral sural SCVs showed positive correlations with total hip BMD T-score in male patients with T2DM (P < 0.05). Bilateral ulnar and tibial MCVs, bilateral sural SCVs, and composite MCV SCV and MSCV Z-scores were independently and positively associated with total hip BMD T-score in male patients with T2DM, respectively (P < 0.05). NCV did not show significant correlation with the total hip BMD T-score in female patients with T2DM.

CONCLUSION

NCV showed positive association with total hip BMD in male patients with T2DM. A decline in NCV indicates an elevated risk of low BMD (osteopenia/osteoporosis) in male patients with T2DM.

Screening and diagnosis of diabetic polyneuropathy in clinical practice: A survey among German physicians (PROTECT Study Survey)

AIMS

We sought to obtain detailed information on the procedures and appraisal of screening for and diagnosing diabetic sensorimotor polyneuropathy (DSPN) in clinical practice.

METHODS

This cross-sectional survey included 574 physicians from 13 federal states across Germany who responded to a tripartite questionnaire.

RESULTS

The vast majority of the respondents reported to screen for DSPN at least once a year (87 %), while 65 % reported to examine the feet of DSPN patients at least twice a year. However, only 28 % and 20 % of the respondents used questionnaires and scores to assess the severity of neuropathic symptoms and signs, respectively. The rates of participants reporting that they do not use a standardized testing procedure were 58 % for pressure sensation, 62 % for pain sensation, and 54 % for thermal sensation. The rates of respondents reporting that they do not deploy a standardized assessment were 41 % for vibration sensation, 73 % for pressure sensation, 77 % for pain sensation, and 66 % for thermal sensation. Half of the physicians oriented themselves towards clinical guidelines when diagnosing DSPN.

CONCLUSIONS

Despite relatively high screening rates, the willingness to implement both standardized testing procedures and assessment and to follow guidelines is low among physicians when screening for and clinically diagnosing DSPN.

[Role of B vitamins, thiamine, pyridoxine, and cyanocobalamin in back pain and other musculoskeletal conditions: a narrative review]

Low back pain, as well as other musculoskeletal disorders (neck pain, osteoarthritis, etc.), are a very frequent cause of consultation both in primary care and in other hospital specialties and are usually associated with high functional and work disability. Acute low back pain can present different nociceptive, neuropathic and nonciplastic components, which leads to consider it as a mixed type pain. The importance of the concept of mixed pain is due to the fact that the symptomatic relief of these pathologies requires a multimodal therapeutic approach to various pharmacological targets. The antinociceptive role of the B vitamin complex has been recognized for several decades, specifically the combination of Thiamine, Pyridoxine and Cyanocobalamin (TPC). Likewise, there is accumulated evidence that indicates an adjuvant analgesic action in low back pain. The aim of the present review is to present the existing evidence and the latest findings on the therapeutic effects of the TPC combination in low back pain. Likewise, some of the most relevant mechanisms of action involved that can explain these effects are analyzed. The reviewed evidence indicates that the combined use of PCT has an adjuvant analgesic effect in mixed pain, specifically in low back pain and other musculoskeletal disorders with nociceptive and neuropathic components. This effect can be explained by an anti-inflammatory, antinociceptive, neuroprotective and neuromodulatory action of the TPC combination on the descending pain system.

Bacterial diversity and inflammatory response at first-time visit in younger and older individuals with diabetic foot infection (DFI)

AIM

Infection of a diabetic foot ulcer (DFU) is common. More than the half of DFUs become infected and 15-20% of them necessitate amputation in course of treatment. Diabetic foot infection (DFI) is therefore the major cause for non-traumatic lower limb amputation in Germany. Prompt and effective treatment of DFI is mandatory to safe limbs and lives. We investigated if there are relevant differences in evoked inflammatory response between different species and age-separated groups. We further investigated if there is an impact of ulcer localization on bacterial diversity.

METHODS

For a 12-month period, we investigated 353 individuals with infected DFU, their laboratory results and bacterial diversity at first-time visit in a Diabetic Foot Care Center in Southern Germany.

RESULTS

The ulcer microbiota was dominated by gram-positive species, primary Staphylococcus aureus. The gram-negative sector was mainly formed by Pseudomonas aeruginosa and Enterobacteriaceae (Proteus spp., Enterobacter spp., Escherichia coli and Klebsiella spp.). With increase in age, P. aeruginosa and S. aureus became more frequent, while Streptococci decreased. Ischemic and/or deep wounds were more likely to bear gram-negative species. Inflammatory response did not differ between gram-positive and gram-negative species, while Streptococci and Proteus spp. induced the highest serum inflammation reaction in their category. Streptococci, Enterobacter spp. and E. coli were more frequent in summer, while Enterococci spp., coagulase-negative Staphylococci and P. aeruginosa were more prevalent in winter half-year. DFIs of the forefoot and plantar side are mostly caused by gram-positive species, while Enterobacteriaceae were most frequent in plantar ulcerations.

CONCLUSION

Gram-positive species dominate bacterial spectrum in DFI. With increase in age, S. aureus, Streptococci and Pseudomonas aeruginosa became more frequent. The inflammatory response did not differ significantly between different species, but gram-negative species were slightly but not significant more frequent in ischemic wounds. Climatic distinction like summer or winter half-year as well as foot ulcer localization seems to influence bacterial diversity in DFUs.

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.