Clinical screening and diagnosis of diabetic polyneuropathy: the North Catalonia Diabetes Study

Association between diabetic eye disease and other complications of diabetes: Implications for care. A systematic review

The aim of this systematic review was to examine the associations between diabetic retinopathy (DR) and the common micro- and macrovascular complications of diabetes mellitus, and how these could potentially affect clinical practice. A structured search of the PubMed database identified studies of patients with diabetes that assessed the presence or development of DR in conjunction with other vascular complications of diabetes. From 70 included studies, we found that DR is consistently associated with other complications of diabetes, with the severity of DR linked to a higher risk of the presence of, or of developing, other micro- and macrovascular complications. In particular, DR increases the likelihood of having or developing nephropathy and is also a strong predictor of stroke and cardiovascular disease, and progression of DR significantly increases this risk. Proliferative DR is a strong risk factor for peripheral arterial disease, which carries a risk of lower extremity ulceration and amputation. Additionally, our findings suggest that a patient with DR has an overall worse prognosis than a patient without DR. In conclusion, this analysis highlights the need for a coordinated and collaborative approach to patient management. Given the widespread use of DR screening programmes that can be performed outside of an ophthalmology office, and the overall cost-effectiveness of DR screening, the presence and severity of DR can be a means of identifying patients at increased risk for micro- and macrovascular complications, enabling earlier detection, referral and intervention with the aim of reducing morbidity and mortality among patients with diabetes. Healthcare professionals involved in the management of diabetes should encourage regular DR screening.

Correlations among Diabetic Microvascular Complications: A Systematic Review and Meta-analysis

Early detection of diabetic microvascular complications is of great significance for disease prognosis. This systematic review and meta-analysis aimed to investigate the correlation among diabetic microvascular complications which may indicate the importance of screening for other complications in the presence of one disorder. PubMed, Embase, and the Cochrane Library were searched and a total of 26 cross-sectional studies met our inclusion criteria. Diabetic retinopathy (DR) had a proven risk association with diabetic kidney disease (DKD) [odds ratio (OR): 4.64, 95% confidence interval (CI): 2.47-8.75, p < 0.01], while DKD also related to DR (OR: 2.37, 95% CI: 1.79-3.15, p < 0.01). In addition, DR was associated with diabetic neuropathy (DN) (OR: 2.22, 95% CI: 1.70-2.90, p < 0.01), and DN was related to DR (OR: 1.73, 95% CI: 1.19-2.51, p < 0.01). However, the risk correlation between DKD and DN was not definite. Therefore, regular screening for the other two microvascular complications in the case of one complication makes sense, especially for patients with DR. The secondary results presented some physical conditions and comorbidities which were correlated with these three complications and thus should be paid more attention.

Alpha lipoic acid combined with epalrestat: a therapeutic option for patients with diabetic peripheral neuropathy

Background

Alpha lipoic acid (ALA), a type of antioxidant, is used in combination with epalrestat in the treatment of diabetic peripheral neuropathy (DPN). However, whether combined treatment is superior to epalrestat monotherapy is controversial.

Methods

We conducted a systematic search of PubMed, Cochrane Library and Chinese databases to identify all randomized controlled trials (RCTs) up to October 31, 2017. Data were extracted to evaluate methodological quality and analyzed using Review Manager 5.3.0 software.

Results

Twelve studies were included. Compared to epalrestat monotherapy, ALA 600 mg/d once a day (qd) combined with epalrestat 50 mg three times a day (tid) augmented the total effectiveness rate (14 days – risk ratio [RR]: 1.40, 95% CI: 1.16–1.69, P=0.0005; 28 days – RR: 1.48, 95% CI: 1.27–1.72, P<0.00001); at the same, it could improve the median motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV), peroneal MNCV, and SNCV after 14, 21, and 28 days of treatment and could reduce the Toronto Clinical Scoring System (TCSS) (weighted mean difference [WMD]: −1.60, 95% CI: (−2.91, −0.29), P=0.02) and Total Symptom Score (TSS) (WMD: −0.93, 95% CI: −1.27, −0.60, P<0.00001) after 21 days of treatment. The treatment strategy of ALA 300 mg/d qd combined with epalrestat 50 mg tid had the same effects in regard to the total effectiveness rate (RR: 1.37, 95% CI: 1.18–1.59, P<0.0001), median MNCV (WMD: 6.12, 95% CI: 5.04, 7.20, P=0.00001), median SNCV (WMD: 6.70, 95% CI: 5.75, 7.65, P=0.00001), peroneal MNCV (WMD: 6.68, 95% CI: 5.82, 7.55, P=0.00001), and peroneal SNCV (WMD: 4.27, 95% CI: 3.34, 5.20, P=0.00001) after 28 days of treatment.

Conclusion

ALA combined with epalrestat is an effective option for DPN patients. Future large-sample RCTs should be conducted to further confirm this finding.

Retinal Neurodegeneration Associated With Peripheral Nerve Conduction and Autonomic Nerve Function in Diabetic Patients

OBJECTIVE

In this study, we evaluated the correlation of retinal thickness with peripheral nerve conduction and autonomic nerve function in diabetic patients.

DESIGN

Cross-sectional study.

METHODS

Medical records of 160 patients (mean age, 63.61 ± 12.52 years) with diabetes without diabetic retinopathy or mild nonproliferative diabetic retinopathy (NPDR) were reviewed. The mean retinal thickness of the parafoveal area and ganglion cell/inner plexiform layer (GC-IPL) thickness in 6 macular regions were measured using optical coherence tomography. Peripheral nerve conduction studies were conducted on peroneal and posterior tibial motor nerves and the sural sensory nerve. Five cardiovascular autonomic function tests were performed. We classified patients into groups by severity of peripheral neuropathy and autonomic dysfunction and analyzed the correlations with mean retinal thickness.

RESULTS

The mean retinal thickness of the parafovea was 315.05 ± 12.70 μm and mean macular GC-IPL thickness was 79.89 ± 4.70 μm. Macular GC-IPL thickness showed significant correlation with peripheral nerve conduction (no peripheral neuropathy vs definite peripheral neuropathy: 82.0 ± 4.8 μm vs 75.2 ± 3.8 μm, P < .001). GC-IPL thickness decreased with severity of autonomic nerve dysfunction (no/mild dysfunction vs severe dysfunction: 81.2 ± 6.6 μm vs 77.6 ± 5.9 μm, P = .005). There was no significant correlation between the retinal thickness of the parafovea and electrodiagnostic tests.

CONCLUSION

The decrease of GC-IPL thickness was positively correlated with both peripheral nerve conduction and autonomic nerve function in diabetic patients who presented with no diabetic retinopathy or mild NPDR.

Interrater Reliability of Four Sensory Measures in People with Multiple Sclerosis

BACKGROUND

Sensory disturbances are a major problem for people with multiple sclerosis (MS), and up to 80% of people with MS present with various sensory deficits. To date, only one study has investigated the reliability of sensory measures in people with MS. We sought to determine the interrater reliability of the verbal analogue scale (VAS), the Erasmus MC modifications to the revised Nottingham Sensory Assessment (EmNSA), Semmes-Weinstein monofilaments (SWMs), and the neurothesiometer (NT) in people with MS.

METHODS

A random sample of 34 people with MS who could walk independently with or without a device was tested by two raters on the same day. For categorical data, percentage agreement, Cohen's kappa, and prevalence-adjusted bias-adjusted kappa were used. For continuous data, interclass correlation coefficient (ICC[2,1]) with 95% confidence intervals (95% CIs), Bland and Altman analysis, and standard error of measurement (SEM) were calculated.

RESULTS

For NT, ICC(2,1) values were good, with the highest for first metatarsophalangeal joint (ICC[2,1] = 0.84, 95% CI = 0.69-0.92, SEM = 4.98). The highest ICC(2,1) for VAS was for the question relating to feeling numbness in the hand (ICC[2,1] = 0.93, 95% CI = 0.86-0.96, SEM = 0.64). Findings for EmNSA and SWMs need further verification owing to possible ceiling effects.

CONCLUSIONS

The NT and VAS had good interrater reliability and should be considered for measuring sensation in ambulatory people with MS. Findings for EmNSA and SWMs revealed either questionable or poor reliability, suggesting the need for further investigation.

Assessment scales for the diagnosis of polyneuropathy

Epidemiological studies that investigate the occurrence and determinants of chronic length-dependent polyneuropathy are scarce. Population-based studies on polyneuropathy require a valid and reliable screening protocol with both good sensitivity and specificity. Several questionnaires and scoring scales have been developed for the detection of polyneuropathy, grading the severity of the disease, or evaluating the clinical course during follow-up. This review summarizes the aims and content of existing diagnostic polyneuropathy screening tools in order to help future studies decide which scale to use for screening in specific situations. We searched the PubMed database and identified 27 scales, 13 are based on symptoms alone, 8 on neurological signs alone, and 6 on a combination of symptoms and signs. Scales that combine questions concerning symptoms and a neurological examination with a focus on sensory alterations seem to have the best discriminatory power. However, all scoring scales were developed for and investigated in prespecified patient populations. Therefore, the generalizability of specific findings to the general population may be limited. We also discuss other limitations of existing scales. Future studies are required to determine which clinimetrically well-developed scales are preferred for use in population-based studies.

Blink reflex in type 2 diabetes mellitus

PURPOSE

An evaluation of the extent of damage of the central nervous system in diabetes mellitus is of high value in current research. Electrophysiological abnormalities are frequently present in asymptomatic patients with diabetes mellitus. Diabetic cranial neuropathy is one of the complications of the disease. Blink reflex is used to diagnose subclinical cranial neuropathy. The objective is to test the utility of blink reflex in detecting subclinical cranial nerve involvement in patients with type 2 diabetes mellitus.

METHODS

Forty patients with type 2 diabetes mellitus, aged from 30 to 60 years examined clinically and neurologically. Blink reflex and nerve conduction studies for the upper and lower limbs were performed and compared with 20 matched normal controls.

RESULTS

Diabetic patients with peripheral neuropathy showed significant prolonged distal latency and reduced amplitudes of the R2C response compared with the control, patients without peripheral neuropathy showed insignificant changes. Alteration of R2 correlated with the type of treatment and the duration of the disease. In patients without peripheral neuropathy, ulnar sensory distal latencies showed significant positive correlation with R2I latency, whereas its Conduction Velocity (CV) showed significant positive correlation with R2C amplitudes and negative correlation with R2C latency.

CONCLUSIONS

R2C is the most sensitive parameter in the blink reflex, which can help in the diagnosis of subclinical diabetic cranial neuropathy.

Cardiovascular disease predicts diabetic peripheral polyneuropathy in subjects with type 2 diabetes: A 10-year prospective study

BACKGROUND

The relationship between cardiovascular disease and diabetic peripheral neuropathy is mainly sustained by data retrieved from cross-sectional studies focused on cardiovascular risk factors. We aimed to assess the presence of cardiovascular disease as a risk factor for developing diabetic peripheral neuropathy in a type 2 diabetes mellitus population.

METHOD

A 10-year prospective, primary care, multicentre study in a randomly selected cohort. Cardiovascular disease presence included stroke, coronary artery disease and/or peripheral ischaemia. Diabetic peripheral neuropathy diagnosis was based on clinical neurological examination as well as the neuropathy symptoms score and nerve conduction studies.

RESULTS

Three hundred and ten (N=310) patients were initially recruited. Two-hundred and sixty seven (N=267) patients were included in the study. Diabetic peripheral neuropathy cumulative incidence was 18.3% (95% confidence intervals 14.1-23.4; N=49). Diabetic peripheral neuropathy development was significantly more frequent in participants presenting with cardiovascular disease at baseline (P=0.01). In the final logistic regression analysis, the presence of cardiovascular disease remained associated with an increased risk for diabetic peripheral neuropathy (odds ratio 2.32, 95% confidence intervals 1.03-5.22) in addition to diabetes duration and low density lipoprotein-cholesterol levels.

CONCLUSIONS

In our series, type 2 diabetes mellitus patients with cardiovascular disease at baseline present with an increased risk of developing diabetic peripheral neuropathy at 10 years of follow-up. Our results suggest that measures aimed at the prevention, control and treatment of cardiovascular disease can also help prevent diabetic peripheral neuropathy development.

How the impact of median neuropathy on sensorimotor control capability of hands for diabetes: an achievable assessment from functional perspectives

To comprehend the sensorimotor control ability in diabetic hands, this study investigated the sensation, motor function and precision pinch performances derived from a pinch-holding-up activity (PHUA) test of the hands of diabetic patients and healthy subjects. The precision, sensitivity and specificity of the PHUA test in the measurements of diabetic patients were also analyzed. We hypothesized that the diabetic hands would have impacts on the sensorimotor functions of the hand performances under functionally quantitative measurements. One hundred and fifty-nine patients with clinically defined diabetes mellitus (DM) and 95 age- and gender-matched healthy controls were included. Semmes-Weinstein monofilament (SWM), static and moving two-point discrimination (S2PD and M2PD), maximal pinch strength and precision pinch performance tests were conducted to evaluate the sensation, motor and sensorimotor status of the recruited hands. The results showed that there were significant differences (all p<0.05) in SWM, S2PD, M2PD and maximum pinch strength between the DM and control groups. A higher force ratio in the DM patients than in the controls (p<0.001) revealed a poor ability of pinch force adjustment in the DM patients. The percentage of maximal pinch strength was also significantly different (p<0.001) between the DM and control groups. The sensitivity, specificity and area under the receiver operating characteristic curve were 0.85, 0.51, and 0.724, respectively, for the PHUA test. Statistically significant degradations in sensory and motor functions and sensorimotor control ability were observed in the hands of the diabetic patients. The PHUA test could be feasibly used as a clinical tool to determine the sensorimotor function of the hands of diabetic patients from a functional perspective.

Cross sectional study to evaluate the effect of duration of type 2 diabetes mellitus on the nerve conduction velocity in diabetic peripheral neuropathy

OBJECTIVE

To study the nerve conduction velocity in clinically undetectable and detectable peripheral neuropathy in type 2 diabetes mellitus with variable duration.

MATERIAL AND METHODS

This cross sectional study was conducted in diagnosed type 2 diabetes mellitus patients. They were divided in groups: Group I (n=37) with clinically detectable diabetic peripheral neuropathy of shorter duration and Group II (n=27) with clinically detectable diabetic peripheral neuropathy of longer duration. They were compared with T2DM patients (n=22) without clinical neuropathy. Clinical diagnosis was based on neuropathy symptom score (NSS) and neuropathy disability score (NDS) for signs. Nerve conduction velocity was measured in both upper and lower limbs. Median, ulnar, common peroneal and posterior tibial nerves were selected for motor nerve conduction study and median and sural nerves were selected for sensory nerve conduction study.

RESULTS

The comparisons were done between nerve conduction velocities of motor and sensory nerves in patients of clinically detectable neuropathy and patients without neuropathy in type 2 diabetes mellitus population. This study showed significant electrophysiological changes with duration of disease. Nerve conduction velocities in lower limbs were significantly reduced even in patients of shorter duration with normal upper limb nerve conduction velocities.

CONCLUSION

Diabetic neuropathy symptom score (NSS) and neuropathy disability score (NDS) can help in evaluation of diabetic sensorimotor polyneuropathy though nerve conduction study is more powerful test and can help in diagnosing cases of neuropathy.

Assessment of the medial dorsal cutaneous, dorsal sural, and medial plantar nerves in impaired glucose tolerance and diabetic patients with normal sural and superficial peroneal nerve responses

OBJECTIVE

This study evaluated the nerve conduction study (NCS) parameters of the most distal sensory nerves of the lower extremities-namely, the medial dorsal cutaneous (MDC), dorsal sural (DS), and medial plantar (MP) nerves-in diabetic (DM) and impaired glucose tolerance (IGT) patients who displayed normal findings on their routine NCSs.

RESEARCH DESIGN AND METHODS

Standard NCSs were performed on healthy control (HC), DM, and IGT groups (N = 147). The bilateral NCS parameters of the MDC, DS, and MP nerves were investigated. The Toronto Clinical Scoring System (TCSS) was assessed for the DM and IGT groups.

RESULTS

The mean TCSS scores of the IGT and DM groups were 2.5 ± 2.3 and 2.8 ± 2.2, respectively. No significant differences between the two groups were observed. After adjustment of age and BMI, the DM group showed significant NCS differences in DS and MDC nerves compared with the HC group (P < 0.05). These differences were also exhibited in the left DS of the IGT group (P = 0.0003). More advanced NCS findings were observed in the DM group. Bilateral abnormal NCS responses in these distal sensory nerves were found in 40 and 16% of DM and IGT patients, respectively.

CONCLUSIONS

These results showed that the simultaneous assessment of the most distal sensory nerves allowed the detection of early NCS changes in the IGT and DM groups, even when the routine NCS showed normal findings.

Angiotensin-converting enzyme gene single polymorphism as a genetic biomarker of diabetic peripheral neuropathy: longitudinal prospective study

BACKGROUND

Identifying patients at risk of developing diabetic peripheral neuropathy (DPN) is of paramount importance in those with type 2 diabetes mellitus (T2DM) to provide and anticipate secondary prevention measures as well as intensify action on risk factors, particularly so in primary care. Noteworthy, the incidence of DPN remains unknown in our environment.

AIMS

(i) To analyze a single angiotensin-converting enzyme (ACE) gene polymorphism (D/I) as a genetic marker of risk of developing DPN, and (ii) to determine the incidence of DPN in our environment.

RESEARCH DESIGN AND METHODS

Longitudinal study with annual follow-up for 3years involving a group of T2DM (N=283) randomly selected. ACE gene polymorphism distribution (I=insertion; D=deletion) was determined. DPN was diagnosed using clinical and neurophysiology evaluation.

RESULTS

Baseline DPN prevalence was 28.97% (95% CI, 23.65-34.20). ACE polymorphism heterozygous genotype D/I presence was 60.77% (95% CI, 55.05-66.5) and was independently associated with a decreased risk of DPN (RR, 0.51; 95% CI, 0.30-0.86). DPN correlated with age (P<0.001) but not with gender (P=0.466) or time of evolution of T2DM (P=0.555). Regarding end point, DPN prevalence was 36.4% (95% CI, 30.76-42.04), and accumulated incidence was 10.4% 3years thereafter. In the final Poisson regression analysis, the presence of heterozygous genotype remained independently associated with a decreased risk of DPN (RR, 0.71; (95% CI, 0.53-0.96). DPN presence remained correlated with age (P=0.002), but not with gender (P=0.490) or time of evolution (P=0.630).

CONCLUSIONS

In our series, heterozygous ACE polymorphism (D/I) stands as a protective factor for DPN development. Accumulated incidence of DPN was relevant. Further prospective studies are warranted.

Glycated hemoglobin A₁c (HbA₁c) and diabetes: a new era?

Abstract In January 2011 the American Diabetes Association (ADA) published the latest guidelines for the diagnosis and treatment of diabetes mellitus (DM)(1,2). Despite some controversies, glycated hemoglobin A(1c) (HbA(1c)), an established marker of long-term glycemia traditionally used to assess the quality of DM management, remained an independent criterion for the diagnosis of DM, and indeed now appears to be well established in the USA. This has far-reaching implications for clinical practice worldwide.

Transforming growth factor beta 1 as a biomarker of diabetic peripheral neuropathy: cross-sectional study

BACKGROUND

Simple and efficient screening methods are lacking for diabetic peripheral neuropathy (DPN), the most common and most difficult to treat of the long-term diabetic complications. Increased levels of transforming growth factor beta 1 (TGFbeta1) in type 2 diabetic patients (T2DM) plays an immunomodulatory role in diabetic nephropathy and, possibly, in atherosclerotic evolution. Since preliminary interrelationships between experimental DPN and TGFbeta1 have been observed, we sought to assess whether TGFbeta1 could be a biomarker molecule for human DPN.

MATERIALS AND METHODS

Cross-sectional cohort study focused on the assessment of the interrelationships between TGFbeta1 levels, cardiovascular disease (CVD), diabetic nephropathy (DNF), and neuropathy (DPN) in a group of T2DM patients (N=180; male 117, female 63) randomly selected from the North Catalonia Diabetes Study. DPN was diagnosed using clinical and neurophysiology evaluation. Incipient DNF was assessed by microalbuminuria (MAU). Total TGFbeta1 (without acidification) was measured by immunoassay by ELISA (Promega).

RESULTS

DPN correlated with age, time of diabetes duration, MAU, CVD, and TGFbeta1 (P<.0001). Log-transformed TGFbeta1 (logTGbeta1) was significantly higher in patients with DPN than in those without (P<.0005). LogTGFbeta1 (OR=7.5; P=.006), age (OR=1.1; P<.0005), and logMAU (OR=2.0; P=.016) appear as significant estimators of the occurrence of DPN in our series. The integrated ROC curve evaluation with these three parameters expressed an important sensitivity (78.1%), specificity (76.0%), positive predictive value (79.2%), and negative predictive value (70.3%) in relation to DPN presence.

DISCUSSION

TGFbeta1 stands as an important biomarker molecule for DFN and DPN screening in our series. Further prospective studies are warranted.

The Association between Serum GGT Concentration and Diabetic Peripheral Polyneuropathy in Type 2 Diabetic Patients

BACKGROUND

Diabetic peripheral polyneuropathy (DPP) is one of the common complications of diabetes mellitus (DM) and can lead to foot ulcers or amputation. The pathophysiology of DPP includes several factors such as metabolic, vascular, autoimmune, oxidative stress and neurohormonal growth-factor deficiency and recent studies have suggested the use of serum gamma-glutamyl transferase (GGT) as an early marker of oxidative stress. Therefore, we investigated whether serum GGT may be useful in predicting DPP.

METHODS

We assessed 90 patients with type 2 DM who were evaluated for the presence of DPP using clnical neurologic examinations including nerve conduction velocity studies. We evaluated the association between serum GGT and the presence of DPP.

RESULTS

The prevalence of DPP was 40% (36 cases) according to clinical neurological examinations. The serum GGT concentration was significantly elevated in type 2 diabetic patients with DPP compared to patients without DPP (P < 0.01). There were other factors significantly associated with DPP including smoking (P = 0.019), retinopathy (P = 0.014), blood pressure (P < 0.05), aspartate aminotransferase (P = 0.022), C-reactive protein (P = 0.036) and urine microalbumin/creatinine ratio (P = 0.004). Serum GGT was independently related with DPP according to multiple logistic analysis (P < 0.01).

CONCLUSION

This study shows that increased levels of serum GGT may have important clinical implications in the presence of DPP in patients with type 2 diabetes.