A new tool to detect kidney disease in Chinese type 2 diabetes patients: comparison of EZSCAN with standard screening methods

Association of serum stromal cell-derived factor 1 levels with EZSCAN score and its derived indicators in patients with type 2 diabetes

BACKGROUND

The aim of the study was to explore whether plasma stromal cell-derived factor 1 (SDF-1) levels are associated with the EZSCAN score and its derived indicators in patients with type 2 diabetes (T2D).

METHODS

From July 2020 to December 2020, a total of 253 patients with T2D were consecutively recruited. Serum SDF-1 levels were measured by sandwich ELISA. EZSCAN test was applied to evaluate the sudomotor function of each patient, and based on the results, EZSCAN score, cardiac autonomic neuropathy risk score (CANRS) and cardiovascular risk score (CVDRS) were calculated by particular algorithms. In addition, other relevant clinical data were also collected.

RESULTS

With increasing tertiles of serum SDF-1 levels, the CANRS and CVDRS significantly increased (both Pfor trend <0.001), while the EZSCAN score significantly decreased (Pfor trend <0.001). Moreover, serum SDF-1 levels were significantly and positively correlated with the CANRS and CVDRS (r = 0.496 and 0.510, respectively, both P < 0.001), and negatively correlated with the EZSCAN score (r = -0.391, P < 0.001). Furthermore, multivariate linear regression analyses were constructed, and after adjusting for other clinical covariates, serum SDF-1 levels were independently responsible for EZSCAN score (β = -0.273, t = -3.679, P < 0.001), CANRS (β = 0.334, t = 5.110, P < 0.001) and CVDRS (β = 0.191, t = 4.983, P = 0.003).

CONCLUSIONS

SDF-1 levels in serum were independently associated with the EZSCAN score and its derived indicators, such as CANRS and CVDRS in patients with T2D.

The application of sudoscan for screening microvascular complications in patients with type 2 diabetes

The aim of the study was to evaluate the performance of sudoscan in screening diabetic microvascular complications in patients with type 2 diabete mellitus (T2DM). 515 patients with T2DM aged from 23 to 89 years were included for analysis in our study. The mean age was 60.00 ± 11.37 years and the mean duration of T2DM was 8.44 ± 7.56 years. Electrochemical skin conductance (ESC) in hands and feet was evaluated by SUDOCAN. Diabetic peripheral neuropathy (DPN) was diagnosed in 378 patients (44.3%), diabetic kidney disease (DKD) in 161 patients (31.26%), diabetic retinopathy (DR) in 148 patients (28.74%). Hands and feet ESC was significantly and independently associated with the presence of DPN, DKD and DR. Patients with a lower ESC (<60 µS) had 5.63-fold increased likelihood of having DPN, 4.90-fold increased likelihood of having DKD, 1.01-fold increased likelihood of having DR, than those with a higher ESC. Age, duration of T2DM, smoking, renal function and vibration perception thresholds were negatively correlated with ESC. Sudoscan parameters were correlated with diabetic microvascular complications, especially with DPN. Sudoscan could be an effective screening tool in primary health care for early screening microvascular complications.

A formula based on autonomic test using EZSCAN and anthropometric data for diagnosis of DM in China

Clinical diagnosis of diabetes mellitus (DM) is time-consuming and invasive. This study aimed to investigate the efficacy and accuracy of EZSCAN in detecting impaired glucose tolerance (IGT) and diabetes mellitus (DM) in Chinese population, and explore a diagnosis formula based on an autonomic test using EZSCAN measurement and anthropometric data. Eligible subjects (n = 1547) had the following data collected: those of anthropometric and EZSCAN measurements and biochemical tests including FPG, OGTT, HbA1c, and serum lipid tests. The support vector machine (SVM) algorithm method was used to derive a diagnostic formula. In this study, 452 and 263 subjects were diagnosed with T2DM and IGT, respectively, while 832 had normal glucose tolerance (NGT). The sensitivity rates for the formula were 77.2% for T2DM and 80.4% for IGT. The diagnostic formula was found to correlate strongly with EZSCAN values. The diagnostic formula based on autonomic test and anthropometric data appears to be a convenient and accurate routine screening option in the Chinese population.

Sudomotor dysfunction independently predicts incident cardiovascular-renal events and all-cause death in type 2 diabetes: the Joint Asia Diabetes Evaluation register

BACKGROUND

Early detection and risk factor control prevent chronic kidney disease (CKD) progression. Evaluation of peripheral autonomic dysfunction may detect incident cardiovascular-renal events in type 2 diabetes (T2D).

METHODS

SUDOSCAN, a non-invasive tool, provides an age-adjusted electrochemical skin conductance (ESC) composite score incorporating hands/feet ESC measurements, with a score ≤53 indicating sudomotor dysfunction. A consecutive cohort of 2833 Chinese adults underwent structured diabetes assessment in 2012-13; 2028 participants without preexisting cardiovascular disease (CVD) and CKD were monitored for incident cardiovascular-renal events until 2015.

RESULTS

In this prospective cohort {mean age 57.0 [standard deviation (SD) 10.0] years; median T2D duration 7.0 [interquartile range (IQR) 3.0-13.0] years; 56.1% men; 72.5% never-smokers; baseline ESC composite score 60.7 (SD 14.5)}, 163 (8.0%) and 25 (1.2%) participants developed incident CKD and CVD, respectively, after 2.3 years of follow-up. The adjusted hazard ratios (aHRs) per 1-unit decrease in the ESC composite score for incident CKD, CVD and all-cause death were 1.02 [95% confidence interval (CI) 1.01-1.04], 1.04 (1.00-1.07) and 1.04 (1.00-1.08), respectively. Compared with participants with an ESC composite score >53, those with a score ≤53 had an aHR of 1.56 (95% CI 1.09-2.23) for CKD and 3.11 (95% CI 1.27-7.62) for CVD, independent of common risk markers. When added to clinical variables (sex and duration of diabetes), the ESC composite score improved discrimination of all outcomes with appropriate reclassification of CKD risk.

CONCLUSIONS

A low ESC composite score independently predicts incident cardiovascular-renal events and death in T2D, which may improve the screening strategy for early intervention.

Sudomotor function testing by electrochemical skin conductance: does it really measure sudomotor function?

OBJECTIVE

Electrochemical skin conductance (ESC) is a non-invasive test of sweat function developed as a potential marker of small fiber neuropathy. Here we systematically review the evolution of this device and the data obtained from studies of ESC across different diseases.

METHODS

Electronic databases, including MEDLINE, and Google Scholar were searched through to February 2018. The search strategy included the following terms: "electrochemical skin conductance," "EZSCAN," and "Sudoscan." The data values provided by each paper were extracted, where available, and input into tabular and figure data for direct comparison.

RESULTS

Thirty-seven studies were included this systematic review. ESC did not change by age or gender, and there was significant variability in ESC values between diseases, some of which exceeded control values. Longitudinal studies of disease demonstrated changes in ESC that were not biologically plausible. Of the 37 studies assessed, 25 received support from the device manufacturer. The extracted data did not agree with other published normative values. Prior studies do not support claims that ESC is a measure of small fiber sensory function or autonomic function.

CONCLUSIONS

Although many papers report significant differences in ESC values between disease and control subjects, the compiled data assessed in this review raises questions about the technique. Many of the published results violate biologic plausibility. A single funding source with a vested interest in the study outcomes has supported most of the studies. Normative values are inconsistent across publications, and large combined data sets do not support a high sensitivity and specificity. Finally, there is insufficient evidence supporting the claim that Sudoscan tests sudomotor or sensory nerve fiber function.

Detection of relationships between SUDOSCAN with estimated glomerular filtration rate (eGFR) in Chinese patients with type 2 diabetes

OBJECTIVE

SUDOSCAN (Impeto Medical, Paris, France) has been proved to be a new and non-invasive method in detecting renal dysfunction in type 2 diabetes mellitus (T2DM) patients. In this study, we sought to compare the result of diabetic kidney dysfunction score (DKD-score) of SUDOSCAN with estimated glomerular filtration rate (eGFR) by using quantile regression analysis, which was completely different from previous studies.

METHODS

A total number of 223 Chinese T2DM patients were enrolled in the study. SUDOSCAN, renal function test (including blood urea nitrogen, creatinine and uric acid) and ⁹⁹mTc-diethylenetriamine pentaacetic acid (⁹⁹mTc-DTPA) renal dynamic imaging were performed in all T2DM patients. DKD-score of SUDOSCAN was compared with eGFR detected by ⁹⁹mTc-DTPA renal dynamic imaging through quantile regression analysis. Its validation and utility was further determined through bias and precision test.

RESULTS

The quantile regression analysis demonstrated the relationship with eGFR was inverse and significant for almost all percentiles of DKD-score. The coefficients decreased as the percentile of DKD-score increased. And in validation data set, both the bias and precision were increased with the eGFR (median difference, -21.2 ml/min/1.73 m² for all individuals vs. -4.6 ml/min/1.73 m² for eGFR between 0 and 59 ml/min/1.73 m²; interquartile range [IQR] for the difference, -25.4 ml/min/1.73 m² vs. -14.7 ml/min/1.73 m²). The eGFR category misclassification rate were 10% in eGFR 0-59 ml/min/1.73 m² group, 57.3% in 60-90 group, and 87.2% in eGFR > 90 ml/min/1.73 m² group.

CONCLUSION

DKD-score of SUDOSCAN could be used to detect renal dysfunction in T2DM patients. A higher prognostic value of DKD-score was detected when eGFR level was lower.

EZSCAN for undiagnosed type 2 diabetes mellitus: A systematic review and meta-analysis

OBJECTIVES

The EZSCAN is a non-invasive device that, by evaluating sweat gland function, may detect subjects with type 2 diabetes mellitus (T2DM). The aim of the study was to conduct a systematic review and meta-analysis including studies assessing the performance of the EZSCAN for detecting cases of undiagnosed T2DM.

METHODOLOGY/PRINCIPAL FINDINGS

We searched for observational studies including diagnostic accuracy and performance results assessing EZSCAN for detecting cases of undiagnosed T2DM. OVID (Medline, Embase, Global Health), CINAHL and SCOPUS databases, plus secondary resources, were searched until March 29, 2017. The following keywords were utilized for the systematic searching: type 2 diabetes mellitus, hyperglycemia, EZSCAN, SUDOSCAN, and sudomotor function. Two investigators extracted the information for meta-analysis and assessed the quality of the data using the Revised Version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. Pooled estimates were obtained by fitting the logistic-normal random-effects model without covariates but random intercepts and using the Freeman-Tukey Arcsine Transformation to stabilize variances. Heterogeneity was also assessed using the I2 measure. Four studies (n = 7,720) were included, three of them used oral glucose tolerance test as the gold standard. Using Hierarchical Summary Receiver Operating Characteristic model, summary sensitivity was 72.0% (95%CI: 60.0%- 83.0%), whereas specificity was 56.0% (95%CI: 38.0%- 74.0%). Studies were very heterogeneous (I2 for sensitivity: 79.2% and for specificity: 99.1%) regarding the inclusion criteria and bias was present mainly due to participants selection.

CONCLUSIONS

The sensitivity of EZSCAN for detecting cases of undiagnosed T2DM seems to be acceptable, but evidence of high heterogeneity and participant selection bias was detected in most of the studies included. More studies are needed to evaluate the performance of the EZSCAN for undiagnosed T2DM screening, especially at the population level.

SUDOSCAN, an effective tool for screening chronic kidney disease in patients with type 2 diabetes

SUDOSCAN is a non-invasive method of measuring peripheral small fiber and autonomic nerve activity by detection of abnormal sweat gland function through electrochemical skin conductance. It has been reported to be an effective screening tool in early detection of microvascular type 2 diabetes mellitus (T2DM) complications including diabetic neuropathy and nephropathy in recent studies. However, previous studies used estimated glomerular filtration rate (eGFR) as the golden standard, which has a 90% chance of being within 30% of the measured GFR at best. No relevant study has been performed in the Chinese population concerning SUDOSCAN in the screening of diabetic nephropathy (DN) in comparison with GFR. In this cross-sectional study, SUDOSCAN was performed in 176 Chinese patients with T2DM between September 2014 and September 2015. It was found that the SUDOSCAN test had a sensitivity of 57.8% and a specificity of 100% to detect chronic kidney disease at a cut-off SUDOSCAN-DN score of 59.5. The area under receiver operating characteristic curve for DN was 0.85 [95% confidence interval (CI), 0.76-0.93] compared with 0.84 for eGFR_MDRD (MDRD, modification of diet in renal disease; 95% CI, 0.71-0.98) and 0.77 for eGFR_EPI (EPI, epidemiology collaboration; 95% CI, 0.68-0.87). Patients with DN score <59.5 had a significantly lower GFR level (P<0.001) and significantly older age (P<0.001), longer duration of T2DM (P<0.001) and higher risk of diabetic complications, including diabetic neuropathy (P<0.001) and peripheral vascular disease (P<0.05). These results suggested that SUDOSCAN may be useful for detecting patients at risk of impaired renal function as part of a screening program in the Chinese population with T2DM.

Study on autonomic dysfunction and metabolic syndrome in Chinese patients

Aims/Introduction

There is still a lack of simple methods and instruments for the early assessment of autonomic dysfunction in metabolic syndrome patients. Assessment of sudomotor function has been proposed to explore autonomic function, and could be used as an early biomarker for metabolic syndrome. In the present study, we use a quick and non‐invasive method to measure sudomotor function, and aimed to evaluate its efficacy to identify metabolic syndrome in a Chinese population.

Materials and Methods

Information on the 1,160 Chinese participants involved in the study, such as age, sex, blood pressure, waist circumference, body mass index, fasting plasma glucose and lipid profile, and SUDOSCAN, was recorded. During the sudomotor test, patients were asked to place their bare hands and feet on large electrodes. The test took 2 min to carry out, was painless and no participant preparation was required.

Results

A total of 567 participants were diagnosed with metabolic syndrome. The prevalence of metabolic syndrome correlated significantly with increasing SUDOSCAN cardiac risk score (P for trend <0.0001). Furthermore, an increase in cardiac risk score value was associated with an increase in the number of metabolic syndrome components (P for trend <0.0001). Compared with the no‐risk group (cardiac risk score <20), participants in the high‐risk group (cardiac risk score ≥30) had a 2.83‐fold increased risk of prevalent metabolic syndrome (P < 0.0001), and 1.51‐fold increased risk (P = 0.01) after adjustments.

Conclusions

Autonomic dysfunction is correlated to components of metabolic syndrome. The role of SUDOSCAN in the screening of at‐risk populations for metabolic syndrome has to be confirmed by further studies.

Alternative Quantitative Tools in the Assessment of Diabetic Peripheral and Autonomic Neuropathy

Here we review some seldom-discussed presentations of diabetic neuropathy, including large fiber dysfunction and peripheral autonomic dysfunction, emphasizing the impact of sympathetic/parasympathetic imbalance. Diabetic neuropathy is the most common complication of diabetes and contributes additional risks in the aging adult. Loss of sensory perception, loss of muscle strength, and ataxia or incoordination lead to a risk of falling that is 17-fold greater in the older diabetic compared to their young nondiabetic counterparts. A fall is accompanied by lacerations, tears, fractures, and worst of all, traumatic brain injury, from which more than 60% do not recover. Autonomic neuropathy has been hailed as the "Prophet of Doom" for good reason. It is conducive to increased risk of myocardial infarction and sudden death. An imbalance in the autonomic nervous system occurs early in the evolution of diabetes, at a stage when active intervention can abrogate the otherwise relentless progression. In addition to hypotension, many newly recognized syndromes can be attributed to cardiac autonomic neuropathy such as orthostatic tachycardia and bradycardia. Ultimately, this constellation of features of neuropathy conspire to impede activities of daily living, especially in the patient with pain, anxiety, depression, and sleep disorders. The resulting reduction in quality of life may worsen prognosis and should be routinely evaluated and addressed. Early neuropathy detection can only be achieved by assessment of both large and small- nerve fibers. New noninvasive sudomotor function technologies may play an increasing role in identifying early peripheral and autonomic neuropathy, allowing rapid intervention and potentially reversal of small-fiber loss.

The Clinical Utility of SUDOSCAN in Chronic Kidney Disease in Chinese Patients with Type 2 Diabetes

There are gaps between recommendations on regular screening for diabetic kidney disease (DKD) and clinical practice especially in busy and low resource settings. SUDOSCAN (Impeto Medical, Paris, France) is a non-invasive technology for assessing sudomotor function using reverse iontophoresis and chronoamperometry which detects abnormal sweat gland function. Vasculopathy and neuropathy share common risk factors and we hypothesized that SUDOSCAN may be used to detect chronic kidney disease (CKD). Between 2012 and 2013, SUDOSCAN was performed in a consecutive cohort of 2833 Hong Kong Chinese adults with type 2 diabetes. Chronic kidney disease was defined as estimated glomerular filtration rate <60 ml/min/1.73m². In this cross-sectional cohort (mean age 58.6±9.5 years, 55.7% male, median disease duration 8 [interquartile range 3–14] years), 5.8% had CKD. At a cut-off SUDOSCAN-DKD score of 53, the test had sensitivity of 76.7%, specificity of 63.4% and positive likelihood ratio of 2.1 to detect CKD. The area under receiver operating characteristic curve for CKD was 0.75 (95% confidence interval 0.72–0.79). Patients without CKD but low score had worse risk factors and complications than those with high score. We conclude that SUDOSCAN may be used to detect patients at risk of impaired renal function as part of a screening program in Chinese population, especially in outreach or low resource settings.

Electrochemical Skin Conductance in Diabetic Kidney Disease

BACKGROUND

There is a need to identify patients with diabetic kidney disease (DKD) using noninvasive, cost-effective screening tests. Sudoscan®, a device using electrochemical skin conductance (ESC) to measure sweat gland dysfunction, is valuable for detecting peripheral neuropathy. ESC was tested for association with DKD (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2)) in 383 type 2 diabetes mellitus (T2D)-affected patients; diagnostic thresholds were determined in 540 patients.

METHODS

Relationships between ESC with eGFR and urine albumin:creatinine ratio (UACR) were assessed in 202 European Americans and 181 African Americans with T2D.

RESULTS

In 92 European American DKD cases and 110 T2D non-nephropathy controls, respectively, mean (SD) ages were 69 (9.7) and 61 (10.8) years, hemoglobin A1c (HbA1c) 7.4 (1.2) and 7.4 (1.3)%, eGFR 29.6 (12.2) and 87.8 (14.2) ml/min/1.73 m(2), and UACR 1,214 (1,705) and 7.5 (5.8) mg/g. In 57 African American cases and 124 controls, respectively, mean (SD) ages were 64.0 (11.9) and 59.5 (9.7) years, HbA1c 7.4 (1.3) and 7.5 (1.7)%, eGFR 29.6 (13.3) and 90.2 (16.2) ml/min/1.73 m(2), and UACR 1,172 (1,564) and 7.8 (7.1) mg/g. Mean (SD) ESC (μS) was lower in cases than controls (European Americans: case/control hands 49.5 (18.5)/62.3 (16.2); feet 62.1 (17.9)/73.6 (13.8), both p < 1.3 × 10(-6); African Americans: case/control hands 39.8 (19.0)/48.5 (17.1); feet 53.2 (21.3)/63.5 (19.4), both p ≤ 0.01). Adjusting for age, sex, body mass index and HbA1c, hands and feet ESC associated with eGFR <60 ml/min/1.73 m(2) (p ≤ 7.2 × 10(-3)), UACR >30 mg/g (p ≤ 7.0 × 10(-3)), UACR >300 mg/g (p ≤ 8.1 × 10(-3)), and continuous traits eGFR and UACR (both p ≤ 5.0 × 10(-9)). HbA1c values were not useful for risk stratification.

CONCLUSIONS

ESC measured using Sudoscan® is strongly associated with DKD in African Americans and European Americans. ESC is a useful screening test to identify DKD in patients with T2D.

The New Age of Sudomotor Function Testing: A Sensitive and Specific Biomarker for Diagnosis, Estimation of Severity, Monitoring Progression, and Regression in Response to Intervention

Sudorimetry technology has evolved dramatically, as a rapid, non-invasive, robust, and accurate biomarker for small fibers that can easily be integrated into clinical practice. Though skin biopsy with quantitation of intraepidermal nerve fiber density is still currently recognized as the gold standard, sudorimetry may yield diagnostic information not only on autonomic dysfunction but also enhance the assessment of the small somatosensory nerves, disease detection, progression, and response to therapy. Sudorimetry can be assessed using Sudoscan™, which measures electrochemical skin conductance (ESC) of hands and feet. It is based on different electrochemical principles (reverse iontophoresis and chronoamperometry) to measure sudomotor function than prior technologies, affording it a much more practical and precise performance profile for routine clinical use with potential as a research tool. Small nerve fiber dysfunction has been found to occur early in metabolic syndrome and diabetes and may also be the only neurological manifestation in small fiber neuropathies, beneath the detection limits of traditional nerve function tests. Test results are robust, accomplished within minutes, require little technical training and no calculations, since established norms have been provided for the effects of age, gender, and ethnicity. Sudomotor testing has been greatly under-utilized in the past, restricted to specialized centers capable of handling the technically demanding and expensive technology. Yet, evaluation of autonomic and somatic nerve function has been shown to be one of the best estimates of cardiovascular risk. Evaluation of sweating has the appeal of quantifiable non-invasive determination of the integrity of the peripheral autonomic nervous system, and can now be accomplished rapidly at point of care clinics with the determination of ESC, allowing intervention for morbid complications prior to permanent structural nerve damage. We review here sudomotor function testing technology, the research evidence accumulated supporting the clinical utility of measuring ESC, the medical applications of sudorimetry now available to physicians with this device, and clinical vignettes illustrating its use in the clinical decision-making process.

A preliminary investigation of EZSCAN™ screening for impaired glucose tolerance and diabetes in a patient population

EZSCAN™ is a non-invasive technology that evaluates sweat gland dysfunction using electrochemical skin conductance measurements, providing an opportunity to determine the risk of impaired glucose tolerance (IGT) and diabetes mellitus (DM). This study was conducted with the aims of detecting IGT and DM and investigating the efficacy and cut-off points of the EZSCAN test in a patient population. The traditional serum and plasma glucose tests were used as comparators. In this cross-sectional study, 270 previously undiagnosed patients (180 women and 90 men) with a high risk of glucose metabolism disorders (≥45 years old) were enrolled. All patients underwent an oral glucose tolerance test (OGTT) and hemoglobin A1c (HbA1c), fasting plasma glucose (FPG) and EZSCAN tests. Forty (14.8%) patients had newly diagnosed DM (NDM), 79 (29.3%) had IGT and 151 (55.9%) had normal glucose tolerance. The EZSCAN values of these groups were 48±11, 47±11 and 34±13%, respectively. For all patients, the correlation coefficient of EZSCAN was 0.462 with the OGTT (P<0.001), 0.182 with the FPG test (P<0.001) and 0.379 with the HbA1c test (P<0.001). The EZSCAN cut-off point for the detection of IGT was 37% [sensitivity, 82%; specificity, 62%; area under the curve (AUC), 0.778], and the cut-off point for NDM was 50% (sensitivity, 53%; specificity, 59%; AUC, 0.528). This study demonstrated that the non-invasive EZSCAN system is an effective screening tool for the detection of glucose dysfunction in the population tested, and that its performance in detecting previously undiagnosed IGT is superior to its performance in detecting DM.

Relationships between electrochemical skin conductance and kidney disease in Type 2 diabetes

BACKGROUND

SUDOSCAN® non-invasively measures peripheral small fiber and autonomic nerve activity using electrochemical skin conductance. Since neuropathy and nephropathy are microvascular Type 2 diabetes (T2D) complications, relationships between skin conductance, estimated glomerular filtration rate (eGFR), and urine albumin:creatinine ratio (UACR) were assessed.

METHODS

Two hundred five African Americans (AA) with T2D, 93 AA non-diabetic controls, 185 European Americans (EA) with T2D, and 73 EA non-diabetic controls were evaluated. Linear models were fitted stratified by population ancestry and T2D, adjusted for covariates.

RESULTS

Relative to EA, AA had lower skin conductance (T2D cases p<0.0001; controls p<0.0001). Skin conductance was also lower in T2D cases vs. controls in each population (p<0.0001, AA and EA). Global skin conductance was significantly associated with eGFR in AA and EA with T2D; adjusting for age, gender, BMI, and HbA1c, positive association was detected between skin conductance and eGFR in AA T2D cases (parameter estimate 3.38, standard error 1.2; p=5.2E(-3)), without association in EA T2D cases (p=0.22).

CONCLUSIONS

Noninvasive measurement of skin conductance strongly associated with eGFR in AA with T2D, replicating results in Hong Kong Chinese. SUDOSCAN® may prove useful as a low cost, non-invasive screening tool to detect undiagnosed diabetic kidney disease in populations of African ancestry.

Neurovascular function and sudorimetry in health and disease

In this review of thermoregulatory function in health and disease, we review the basic mechanisms controlling skin blood flow of the hairy and glabrous skin and illustrate the major differences in blood flow to glabrous skin, which is, in essence, sympathetically mediated, while hairy skin is dependent upon neuropeptidergic signals, nitric oxide, and prostaglandin, among others. Laser Doppler methods of quantification of blood flow--in response to iontophoresis of acetylcholine or heat--and nociceptor-mediated blood flow have relatively uniformly demonstrated an impaired capacity to increase blood flow to the skin in diabetes and in its forerunners, prediabetes and the metabolic syndrome. This reduced capacity is likely to be a significant contributor to the development of foot ulcerations and amputations in diabetes, and means of increasing blood flow are clearly needed. Understanding the pathogenic mechanisms is likely to provide a means of identifying a valuable therapeutic target. Thermoregulatory control of sweating is intimately linked to the autonomic nervous system via sympathetic C fibers, and sweat glands are richly endowed with a neuropeptidergic innervation. Sweating disturbances are prevalent in diabetes and its precursors, and quantification of sweating may be useful as an index of diagnosis of somatic and, probably, autonomic dysfunction. Moreover, quantifying this disturbance in sweating by various methods may be useful in identifying the risk of progression from prediabetes to diabetes, as well as responses to therapeutic intervention. We now have the technological power to take advantage of this physiological arrangement to better understand, monitor, and treat disorders of small nerve fibers and the somatic and autonomic nervous system (ANS). Newer methods of sudomotor function testing are rapid, noninvasive, not technically demanding, and accessible to the outpatient clinic. Whether the potential applications are screening for diabetes, following poorly controlled diabetes subjects during alteration of their treatment regimen, or simply monitoring somatic and autonomic function throughout the course of treatment, sudorimetry can be an invaluable tool for today's clinicians.

Autonomic test by EZSCAN in the screening for prediabetes and diabetes

BACKGROUND

Autonomic neuropathy is common in diabetics and may occur in prediabetes. A new and noninvasive autonomic test-EZSCAN evaluates sudomotor function precisely. No generally accepted EZSCAN thresholds to screen for prediabetes and diabetes have been defined.

METHODOLOGY AND PRINCIPAL FINDINGS

Cross-sectional study of 5, 824 Chinese adults aged 40 and older was conducted in Shanghai, China. We used EZSCAN to evaluate autonomic function in different glucose status and screen for prediabetes and diabetes. The prevalence of prediabetes and diabetes were 21.9% and 17.5% respectively. Compared with the lowest quintile, the highest quintile of EZSCAN value had odds ratios for having dysglycemia (prediabetes or diabetes) of 2.08 (95% CI 1.67-2.58) in total population, 2.89 (95% CI 2.06-4.05) in men and 1.70 (95% CI 1.28-2.25) in women after adjustment for confounding factors. EZSCAN value improved the areas under ROC curve for detection of dysglycemia or diabetes beyond the contribution of conventional risk factors by 0.8% and 12.9%. The cut-off point of EZSCAN value higher than 30% provided reasonable sensitivities (70.3-83.7%) to detect dysglycemia not only in total population regardless of sex but also in individuals with high risk of developing diabetes.

CONCLUSIONS AND SIGNIFICANCE

EZSCAN value higher than 30% indicate an increased risk of prevalent prediabetes and diabetes, suggesting that subjects with EZSCAN ≥30% should be further evaluated by oral glucose tolerance test. The improvement of EZSCAN for diabetes detection was still of limited clinical relevance. Thus the clinical application value of EZSCAN is needed to be explored in future studies.

Accessing autonomic function can early screen metabolic syndrome

Background

Clinical diagnosis of the metabolic syndrome is time-consuming and invasive. Convenient instruments that do not require laboratory or physical investigation would be useful in early screening individuals at high risk of metabolic syndrome. Examination of the autonomic function can be taken as a directly reference and screening indicator for predicting metabolic syndrome.

Methodology and Principal Findings

The EZSCAN test, as an efficient and noninvasive technology, can access autonomic function through measuring electrochemical skin conductance. In this study, we used EZSCAN value to evaluate autonomic function and to detect metabolic syndrome in 5,887 participants aged 40 years or older. The EZSCAN test diagnostic accuracy was analyzed by receiver operating characteristic curves. Among the 5,815 participants in the final analysis, 2,541 were diagnosed as metabolic syndrome and the overall prevalence was 43.7%. Prevalence of the metabolic syndrome increased with the elevated EZSCAN risk level (p for trend <0.0001). Moreover, EZSCAN value was associated with an increase in the number of metabolic syndrome components (p for trend <0.0001). Compared with the no risk group (EZSCAN value 0–24), participants at the high risk group (EZSCAN value: 50–100) had a 2.35 fold increased risk of prevalent metabolic syndrome after the multiple adjustments. The area under the curve of the EZSCAN test was 0.62 (95% confidence interval [CI], 0.61–0.64) for predicting metabolic syndrome. The optimal operating point for the EZSCAN value to detect a high risk of prevalent metabolic syndrome was 30 in this study, while the sensitivity and specificity were 71.2% and 46.7%, respectively.

Conclusions and Significance

In conclusion, although less sensitive and accurate when compared with the clinical definition of metabolic syndrome, we found that the EZSCAN test is a good and simple screening technique for early predicting metabolic syndrome.