Quantitative vibration perception threshold in assessing diabetic neuropathy: is the cut-off value lower for Indian subjects? [Q-VADIS Study]

The accuracy of 10 g monofilament use for clinical screening of diabetes peripheral neuropathy among Indian population

OBJECTIVE

The purpose of this study was to test the diagnostic accuracy of the 10g monofilament to screen for diabetic peripheral neuropathy (DPN) in India. The study further assessed the effect of physical activity, footwear use, and occupation on the outcome.

METHODS

Non-probabilistic purposive sampling was used to recruit patients with T2DM to assess the diagnostic utility of the 10 g monofilament. 160 participants were recruited divided into 4 groups. Each group consisted of 40 participants with 20 under each category described as "Physical Worker Vs Non- physical worker" (n = 40), "Barefoot Vs Footwear" (n = 40), "Use of Slipper at Home Vs No-slippers use at home" (n = 40), "Agriculture Vs Non- agriculture" (n = 40). 10 g monofilament was used to detect the presence of protective sensation towards screening of DPN against biothesiometer (Vibration Pressure Threshold).

RESULTS

The area under the ROC (receiver operating characteristic) curve was 0.6 for identifying DPN using the 10 g monofilament. Physical work (p = 0.04), footwear (p = 0.04), slipper use at home (p = 0.02) and occupation (p = 0.02) impacted on the diagnostic utility of the 10g monofilament.

CONCLUSIONS

This study shows that the 10 g monofilament has limited accuracy for detecting DPN in the Indian population and this is further affected by occupation, socioeconomic and religious practice.

Assessing the vibration perception threshold in a community sample of adult Ghanaians

BACKGROUND

The vibration perception threshold (VPT) helps evaluate human somatosensory function and diagnose peripheral neuropathy. To optimize its use as a primary neurologic tool, it is imperative to establish its typical values in healthy subjects and assess the factors affecting its variability in an individual to ensure consistency in its application.

METHODS

Demographic data and a brief medical history were collected from 391 non-diabetic adults aged 30-80 at Kpone-on-Sea in Ghana. The VPT was measured at the tip of the big toe, the medial malleolus, the tip of the middle finger, and the head of the ulna of each participant using a Horwell Neurothesiometer. The variability of VPT was assessed vis-à-vis the following factors: gender, age, fasting plasma sugar and body mass index.

RESULTS

The mean age of participants was 48.4 ± 0.7 years, and the female-to-male ratio was 1.46. The overall VPT values ranged from 5.74 ± 0.14 volts to 8.55 ± 0.18 volts in the lower limbs and 3.61 ± 0.06 volts to 5.00 ± 0.08 volts in the upper limbs. Age was found to be the only factor that could predict VPT for both the lower and upper limbs (P < 0.001). One-Way Analysis of Variance with Tukey's posthoc showed that the VPT in the feet was significantly higher than that in the hands.

CONCLUSIONS

Generally, the VPT was high on proximal sites and low on distal sites indicating that the vibration sensation increased from proximal to distal direction. Therefore, distal areas should be used for VPT testing with a Neurothesiomer. Age was found to be the only factor that affected VPT variability. Hence, the practical application of VPT will require age-specific reference ranges to cater for older adults.

Assessment of the diagnostic accuracy of Vibrasense compared to a biothesiometer and nerve conduction study for screening diabetic peripheral neuropathy

AIMS

Peripheral neuropathy is a common microvascular complication in diabetes and a risk factor for the development of diabetic foot ulcers and amputations. Vibrasense (Ayati Devices) is a handheld, battery-operated, rapid screening device for diabetic peripheral neuropathy (DPN) that works by quantifying vibration perception threshold (VPT). In this study, we compared Vibrasense against a biothesiometer and nerve conduction study for screening DPN.

METHODS

A total of 562 subjects with type 2 diabetes mellitus underwent neuropathy assessments including clinical examination, 10-g monofilament test, VPT evaluation with Vibrasense and a standard biothesiometer. Those with an average VPT ≥ 15 V with Vibrasense were noted to have DPN. A subset of these patients (N = 61) underwent nerve conduction study (NCS). Diagnostic accuracy of Vibrasense was compared against a standard biothesiometer and abnormal NCS.

RESULTS

Average VPTs measured with Vibrasense had a strong positive correlation with standard biothesiometer values (Spearman's correlation 0.891, P < 0.001). Vibrasense showed sensitivity and specificity of 87.89% and 86.81% compared to biothesiometer, and 82.14% and 78.79% compared to NCS, respectively.

CONCLUSIONS

Vibrasense demonstrated good diagnostic accuracy for detecting peripheral neuropathy in type 2 diabetes and can be an effective screening device in routine clinical settings.

TRIAL REGISTRATION

Clinical trials registry of India (CTRI/2022/11/047002). Registered 3 November 2022.  https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=76167 .

Quantitative vibration perception threshold in assessing diabetic polyneuropathy: Should the cut-off value be adjusted for Chinese individuals with type 2 diabetes?

AIMS/INTRODUCTION

To examine the performance and identify the optimal threshold of vibration perception threshold (VPT) for diagnosing diabetic polyneuropathy (DPN) in a Chinese population according to multiple definitions of DPN as gold standards.

MATERIALS AND METHODS

VPT was determined in 421 Chinese individuals with type 2 diabetes, who simultaneously completed a questionnaire of neuropathic symptoms, and underwent the assessment of signs of peripheral neuropathy and electromyography tests. Three definitions of DPN (i.e., clinician-diagnosed DPN, abnormal nerve conduction and confirmed DPN) were taken as reference gold standards.

RESULTS

Vibration perception threshold was a specific measure for all three groups of DPN outcomes, with the highest specificity noted for clinician-diagnosed DPN (85.1%). The specificity for abnormal nerve conduction and confirmed DPN was 77.0 and 76.6%, respectively. The sensitivity of VPT was 67.0% for clinician-diagnosed DPN, 66.5% for abnormal nerve conduction and 67.2% for confirmed DPN. The optimal cut-off threshold for abnormal nerve conduction, as well as confirmed DPN, was VPT >14.9 V. The specificity and sensitivity of VPT >14.9 V as the cut-off value for clinician-diagnosed DPN were 85.6 and 66.2%, respectively. When taking clinician-diagnosed DPN as the gold standard, the performance of VPT for diagnosing DPN was best with an area under the curve value of 0.804.

CONCLUSIONS

VPT measured using the neurothesiometer had relatively high specificity and best performance for diagnosing DPN when clinician-diagnosed DPN rather than abnormal nerve conduction was taken as the gold standard in a Chinese population. A VPT value of ≥15 V might be equally applicable for diagnosing DPN in a Chinese population.

Clinical study of diabetic peripheral neuropathy screening by retinal vascular geometric parameters

To investigate the relationship between geometrical changes of retinal vessels and diabetic peripheral neuropathy (DPN), and to determine the effectiveness of retinal vascular geometry analysis and vibration perception threshold (VPT) for DPN assessment. Type 2 diabetes patients (n = 242) were categorized by stage of DPN. VPT and fundus photography was performed to obtain retinal vascular geometry parameters. The risk factors for DPN and the correlation between DPN stages were analyzed. The efficiency of the retinal vascular geometric parameters obtained with VPT as a diagnostic tool for DPN was examined. Stages of DPN showed a linear correlation with VPT (r = 0.818), central retinal vein equivalent (CRVE) (r = 0.716), and fractal dimension arterioles (DFa) (r = - 0.769). VPT, CRVE, DFa, and fractal dimension veins (DFv) showed high sensitivity (80%, 55%, 82%, and 67%, respectively) and specificity (92%, 93%, 82%, and 80%, respectively) for DPN diagnosis. Good agreement was observed between combined use of geometric parameters (CRVE, DFa and DFv) and VPT (Kappa value 0.430). The detection rate of DPN with combined use of geometric parameters of retinal vessels (64.88%) was significantly higher than that with use of VPT (47.52%). Retinal vascular geometry changes demonstrated significant correlation with DPN severity. VPT, CRVE, DFa, and DFv may provide insights for understanding DPN.

Prediction of peak plantar pressure for diabetic foot: The regressional model

BACKGROUND

The increase in peak plantar pressure could be the most important etiological factor for pathogenesis of a diabetic foot. Thus the fate of a diabetic foot syndrome which is a clinical triad of neurological, vascular and musculoskeletal changes could be biomechanically predictive and preventive using clinical parameters. In the presence of peripheral neuropathy, certain clinical parameters could be severely altered resulting into increased peak plantar pressure. Therefore the aim of the study was to identify the most important clinical parameters for the prediction of peak plantar pressure between neuropathy and non-neuropathy type 2 diabetes mellitus participants.

METHODOLOGY

A total of 380 participants were recruited under the study and divided into two groups (190 each group). The cross-sectional study was conducted at Kasturba Hosipal, Manipal, India. Multiple regression analysis was performed to find the hyperplane of best fit. Stepwise regression was performed with (α entry=0.15 and α removal=0.2) to select the best subset of predictors.

RESULTS

Adjusted R2 of the final model which included the predictors showed 90.8% variability for the dependent variable.

CONCLUSION

The findings from the regression analysis suggested model was found to be strongly significant in predicting the peak plantar pressure between neuropathy and non-neuropathy type 2 diabetes mellitus participants. Since higher values of peak plantar pressure is strongly associated with risk for future diabetic foot complications, it could be suggested that these clinical parameters could be very useful to assess and should be used in routine clinical practice very effectively.

Prevalence and risk factors of development of peripheral diabetic neuropathy in type 2 diabetes mellitus in a tertiary care setting

AIMS/INTRODUCTION

The study was carried out to assess the prevalence of diabetic peripheral neuropathy (DPN), compare the prevalence between known diabetes mellitus (KDM) and newly detected diabetes mellitus (NDDM), identify risk factors associated, its prevalence pattern and to assess if any sex-specific differences are present.

MATERIALS AND METHODS

A cross-sectional study was carried out in a tertiary care hospital. Patients with duration of diabetes ≤6 months were considered to be NDDM. DPN was diagnosed by the combination of more than one abnormal result of 10-g monofilament, pinprick sensations and ankle reflexes, and categorized according to the severity level using vibration perception threshold. The study included 1,637 KDM and 369 NDDM patients.

RESULTS

A total of 586 participants were found to have DPN, accounting for 29.2% (95% confidence interval [CI] 27.2-31.2) prevalence. The higher prevalence was observed in KDM compared with NDDM 33.7% (95% CI 31.42-36.01) vs 9.2% (95% CI 6.3-12.2; P < 0.001). Prevalence of mild, moderate, and severe neuropathies was 8.06, 14.55 and 6.63%, respectively. Regression analysis showed age (P < 0.001), duration of diabetes (P < 0.001), dyslipidemia (P = 0.03), glycated hemoglobin (P < 0.001), the presence of other microvascular complications (P < 0.001), macrovascular complications (P = 0.003) and alcoholic status (P < 0.033) to be associated. No sex-specific differences were observed in the mean age at diagnosis of diabetes, mean age at the diagnosis of neuropathy, and duration taken for the DPN development among females and males.

CONCLUSIONS

The study showed a high prevalence (29.2%) of DPN among north Indian type 2 diabetes mellitus patients. Thus, timely screening with earlier detection and intervention would be useful in preventing the progression of neuropathy.