C-peptide is independent associated with diabetic peripheral neuropathy: a community-based study

Decreased glucagon in diabetic peripheral neuropathy patients with long duration type 2 diabetes

OBJECTIVE

The aim of this study was to investigate the association of fasting C-peptide and glucagon with diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes (T2DM).

METHODS

A comprehensive evaluation was conducted on 797 patients with T2DM to assess the various risk factors affecting DPN. The subjects were categorized into short duration and long duration group according to the duration of diabetes with a threshold of 10 years. Logistic regression analysis was employed to examine the association between DPN and islet function, as well as other parameters. Receiver operating characteristic curve analysis was performed to evaluate the predictive capability of glucagon.

RESULTS

The fasting C-peptide levels were significantly lower in the DPN patients with short duration of diabetes, but lost significance in the long duration group. Conversely, a decreased level of glucagon was only observed in DPN patients with long duration of diabetes. For the group with long duration of diabetes, glucagon was the sole risk factor associated with DPN. The receiver operating characteristic curve analysis revealed that glucagon in the long duration group exhibited a moderate area under the curve of 0.706.

CONCLUSIONS

The serum glucagon levels in T2DM patients with DPN exhibited bidirectional changes based on the duration of diabetes. Decreased glucagon was associated with DPN in T2DM patients with long duration of diabetes.

Risk Factors for Subclinical Diabetic Peripheral Neuropathy in Type 2 Diabetes Mellitus

Purpose

To investigate the risk factors associated with subclinical diabetic peripheral neuropathy (sDPN) in patients with type 2 diabetes mellitus (T2DM).

Patients and Methods

This cross-sectional, retrospective study involved 311 patients with T2DM who were successively admitted from January 2018 to December 2021 without any neurological symptoms. All participants underwent a nerve conduction study (NCS), and those asymptomatic patients with abnormal nerve conduction were diagnosed with sDPN. Differences between groups were evaluated by the chi-squared, Wilcoxon, or Fisher's exact test. Binary logistic regression analysis was performed to determine the independent risk factors for sDPN. Receiver operating characteristic (ROC) curves were constructed, and the areas under curves (AUCs) were detected.

Results

Among 311 asymptomatic patients with T2DM, 142 (45.7%) with abnormal nerve conduction were diagnosed with sDPN. Patients with sDPN significantly differed from those without diabetic peripheral neuropathy (DPN) in age, history of hypertension, duration of diabetes, anemia, neutrophil-to-lymphocyte ratio, fasting C-peptide level, serum creatinine level, and albuminuria (all p<0.05). Furthermore, the duration of diabetes (odds ratio [OR]: 1.062, 95% confidence interval [CI]: 1.016-1.110), fasting C-peptide level (OR: 2.427, 95% CI: 1.126-5.231), and presence of albuminuria (OR: 2.481, 95% CI: 1.406-4.380) were independently associated with the development of sDPN (all p<0.05). The AUCs for fasting C-peptide level, duration of diabetes, and the two factors combined were 0.6229 (95% CI: 0.5603-0.6855, p=0.0002), 0.6738 (95% CI: 0.6142-0.7333, p<0.0001), and 0.6808 (95% CI: 0.6212-0.7404, p<0.0001), respectively.

Conclusion

For patients with T2DM and longer duration of diabetes, lower fasting C-peptide levels, and presence with albuminuria, the risk for developing DPN is higher even if they have no clinical signs or symptoms. Identifying potential risk factors for the development of sDPN and effectively controlling them early are critical for the successful management of DPN.

The role of C-peptide in diabetes and its complications: an updated review

Worldwide, diabetes and its complications have seriously affected people's quality of life and become a serious public health problem. C-peptide is not only an indicator of pancreatic β-cell function, but also a biologically active peptide that can bind to cell membrane surface signaling molecules and activate downstream signaling pathways to play antioxidant, anti-apoptotic and inflammatory roles, or regulate cellular transcription through internalization. It is complex how C-peptide is related to diabetic complications. Both deficiencies and overproduction can lead to complications, but their mechanisms of action may be different. C-peptide replacement therapy has shown beneficial effects on diabetic complications in animal models when C-peptide is deficient, but results from clinical trials have been unsatisfactory. The complex pattern of the relationship between C-peptide and diabetic chronic complications has not yet been fully understood. Future basic and clinical studies of C-peptide replacement therapies will need to focus on baseline levels of C-peptide in addition to more attention also needs to be paid to post-treatment C-peptide levels to explore the optimal range of fasting C-peptide and postprandial C-peptide maintenance.

Association of C-peptide level with bone mineral density in type 2 diabetes mellitus

This study revealed that there was no significant linear relationship between fasting C-peptide (FCP) level and bone mineral density (BMD) or fracture risk in type 2 diabetes mellitus (T2DM) patients. However, in the FCP ≤ 1.14 ng/ml group, FCP is positively correlated with whole body (WB), lumbar spine (LS), and femoral neck (FN) BMD and negatively correlated with fracture risk.

PURPOSE

To explore the relationship between C-peptide and BMD and fracture risk in T2DM patients.

METHODS

530 T2DM patients were enrolled and divided into three groups by FCP tertiles, and the clinical data were collected. BMD was measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of major osteoporotic fractures (MOFs) and hip fractures (HFs) was evaluated by adjusted fracture risk assessment tool (FRAX).

RESULTS

In the FCP ≤ 1.14 ng/ml group, FCP level was positively correlated with WB, LS, and FN BMD, while FCP was negatively correlated with fracture risk and osteoporotic fracture history. However, FCP was not correlated with BMD and fracture risk and osteoporotic fracture history in the 1.14 < FCP ≤ 1.73 ng/ml and FCP > 1.73 ng/ml groups. The study has shown that FCP was an independent factor influencing BMD and fracture risk in the FCP ≤ 1.14 ng/ml group.

CONCLUSIONS

There is no significant linear relationship between FCP level and BMD or fracture risk in T2DM patients. In the FCP ≤ 1.14 ng/ml group, FCP is positively correlated with WB, LS, and FN BMD and negatively correlated with fracture risk, and FCP is an independent influencing factor of BMD and fracture risk. The findings suggest that FCP may predict the risk of osteoporosis or fracture in some T2DM patients, which has a certain clinical value.

Prevalence of painful diabetic peripheral neuropathy in type 2 diabetes mellitus and diabetic peripheral neuropathy: A nationwide cross-sectional study in mainland China

AIM

The study aimed to assess the prevalence and risk factors of painful diabetic peripheral neuropathy (PDPN) in patients with type 2 diabetes mellitus (T2DM) and diabetic peripheral neuropathy (DPN) in mainland China.

METHODS

This nationwide cross-sectional study enrolled T2DM patients with DPN from 25 provinces in China between July 2017 and December 2017. The prevalence, characteristics, and risk factors of PDPN were analyzed.

RESULTS

Among 25,710 patients with T2DM and DPN, 14,699 (57.2%) had PDPN. The median age was 63 years old. Age over 40 years old, education level, hypertension, myocardial infarction, duration of diabetes of over five years, diabetic retinopathy and nephropathy, moderate total cholesterol, moderate and higher low-density lipoprotein (LDL) increased uric acid (UA) and decreased estimated glomerular filtration rate (eGFR) were independently associated with PDPN (all P < 0.05). Compared with low levels of C-peptide, moderate levels were independently associated with a higher risk of PDPN, while high levels were associated with a lower risk (all P < 0.001).

CONCLUSIONS

In mainland China, more than half of the patients with DPN have neuropathic pain. Patients with older age, lower education level, longer duration of diabetes, lower LDL, increased UA, decreased eGFR, and comorbidities had an increased risk of PDPN.

Aspartate aminotransferase/alanine aminotransferase ratio was associated with type 2 diabetic peripheral neuropathy in a Chinese population: A cross-sectional study

OBJECTIVE

Despite previous research that focused on aspartate aminotransferase/alanine aminotransferase ratio (AAR) as predictors of type 2 diabetes mellitus (T2DM) and cardiovascular disease, there has been limited research evaluating the association between AAR and diabetic microvascular complications. This study aimed to investigate the association of AAR with diabetic peripheral neuropathy (DPN).

METHODS

A total of 1562 hospitalized patients with T2DM were divided into four groups according to AAR quartiles. The relationship between AAR and DPN and related parameters was explored by the Spearman correlation coefficients, multivariable logistic regression analysis, and receiver operating characteristic (ROC) curves.

RESULTS

Patients with higher AAR quartiles had higher levels of vibration perception threshold (VPT) and presence of DPN, and AAR was positively associated with VPT and presence of DPN independent of sex, age, body mass index, and diabetic duration (P<0.01 or P<0.05). Moreover, AAR remained significantly associated with a higher odds ratio (OR) of DPN (OR 2.413, 95% confidence interval [CI] 1.081-5.386, P<0.05) after multivariate adjustment. Additionally, the risk of presence of DPN increased progressively as AAR quartiles increased (all P for trend <0.01) in both male and female subjects, and the highest quartile of AAR of male and female subjects was respectively associated with 107.3% (95% CI: 1.386-3.101; P<0.01) and 136.8% (95% CI: 1.550-3.618; P<0.01) increased odds of DPN compared with the lower quartiles. Last, the analysis of receiver operating characteristic curves revealed that the best cutoff values for AAR to predict the presence of DPN were 0.906 (sensitivity: 70.3%; specificity: 49.2%; and area under the curve [AUC]: 0.618) and 1.402 (sensitivity: 38%; specificity: 81.9%; and AUC: 0.600) in male and female subjects, respectively.

CONCLUSIONS

These findings suggest that the high AAR may be associated with the presence of DPN in Chinese patients with T2DM, and may be used as an additional indicator of risk of DPN.

Correlation of C-Peptide With Complications Observed in Children and Adolescents With Type 1 Diabetes in Tanzania: A Cross-Sectional Survey

Type 1 diabetes mellitus (T1DM) complications corelate with C-peptide levels. However, the C-Peptide role has not been explored in resource limited countries. This study explored the relationship between C-peptide and complications. A cross-sectional study involving participants aged 0 to 25 years with T1DM in Dar es salaam Tanzania, between 2021 and 2022 was done. Diabetes nephropathy and retinopathy were assessed. About 281 (92.4%) participants were screened, 144 (51.2%) were females. Mean age was 19 ± 6 years. Majority 175 (62.3%) had poor glycemic control (HbA1c) > 10%, and low C-Peptide level 201 (71.5%). Retinopathy was 11.7% and risk for nephropathy was 41.3%. About 13.4% and 41.8% with low C peptide had Retinopathy and high-risk nephropathy respectively. Age at diagnosis, poor glycemic control, low c peptide and duration of diabetes were associated with complications. Further prospective studies are needed to capture when complications set in, so to have better strategies to prevent complications.

Candidate metabolite markers of peripheral neuropathy in Chinese patients with type 2 diabetes

OBJECTIVES

To analyze the serum and urine metabolites present in type 2 diabetes mellitus (T2DM) patients and T2DM patients with diabetic peripheral neuropathy (DPN) and to select differentially expressed biomarkers for early diagnosis of DPN.

METHODS

Serum and urine metabolites from 74 T2DM patients with peripheral neuropathy and 41 without peripheral neuropathy were analyzed using gas chromatograph system with time-of-flight mass spectrometer metabolomics to detect biomarkers of peripheral neuropathy in T2DM.

RESULTS

There were increased serum triglycerides, alanine aminotransferase, and decreased C-peptide, and total cholesterol levels in T2DM patients with DPN compared to those without peripheral neuropathy. Metabolomic analysis revealed visible differences in metabolic characteristics between two groups, and overall 53 serum differential metabolites and 56 urine differential metabolites were identified with variable influence on projection (VIP) >1 and P<0.05. To further analyze the correlation between the identified metabolites and DPN, four serum metabolites and six urine metabolites were selected with VIP>2, and fold change (FC) >1, including serum β-alanine, caproic acid, β-alanine/L-aspartic acid, and L-arabinose/L-arabitol, and urine gluconic acid, erythritol, galactonic acid, guanidoacetic acid, cytidine, and aminoadipic acid. Furthermore, five serum biomarkers and six urine biomarkers were found to show significant changes (P<0.05, VIP>1, and FC>1) respectively in patients with mild, moderate, and severe DPN. In addition, we found that glyoxylate and dicarboxylate metabolism was a differential metabolic pathway not only between T2DM and DPN, but also among different degrees of DPN. The differential metabolites such as β-alanine and caproic acid are expected to be biomarkers for DPN patients, and the significant changes in glyoxylate and dicarboxylate metabolism may be related to the pathogenesis of DPN.

CONCLUSION

There were serum and urine spectrum metabolomic differences in patients with DPN, which could serve as biomarkers for T2DM and DPN patients.

The Association of Fasting C-peptide with Corneal Neuropathy in Patients with Type 2 Diabetes

PURPOSE

Damage to corneal nerve fibers has been demonstrated in people with type 2 diabetes mellitus (T2DM) that further progresses with increasing severity of diabetic peripheral neuropathy. However, the role of C-peptide in corneal nerve damage has not been reported in T2DM. The present study investigated the relationship of fasting C-peptide levels with corneal neuropathy evaluated by corneal confocal microscopy (CCM) in patients with T2DM.

METHODS

160 T2DM patients (72 females) aged 34-78 with duration ranging from 0 to 40 years underwent CCM to measure corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), and corneal nerve branch density (CNBD). Pearson correlation analysis and multiple linear regression analysis were used to explore the association of fasting C-peptide levels with corneal nerve parameters. Partial correlation analysis (adjusted for age and gender) was also conducted to analyze the correlation of metabolic indexes with these three corneal nerve parameters. The relationship between fasting C-peptide levels and duration of diabetes was also explored by Pearson correlation analysis.

RESULTS

With an increase in fasting C-peptide levels, the values of CNFL, CNFD, and CNBD also showed a corresponding trend for an increase. Partial correlation analysis revealed that fasting C-peptide levels were positively associated with CNFL (r = 0.245, P = 0.002), CNFD (r = 0.180, P = 0.024), and CNBD (r = 0.214, P = 0.008) after adjusting for age and gender. Using multiple linear regression analysis, fasting C-peptide levels were also closely associated with CNFL (P = 0.047) and CNBD (P = 0.038) after multiple adjustments. However, this association disappeared after further adjusting for duration of diabetes. Further analysis indicated that fasting C-peptide levels declined with duration of diabetes (r = -0.267, P = 0.001).

CONCLUSIONS

C-peptide was closely associated with corneal neuropathy and disease duration in T2DM. C-peptide levels might be both an indicator of beta-cell function and a marker of disease severity (such as diabetic corneal neuropathy) and duration.

Associations of serum low-density lipoprotein and systolic blood pressure levels with type 2 diabetic patients with and without peripheral neuropathy: systemic review, meta-analysis and meta-regression analysis of observational studies

BACKGROUND

Compositional abnormalities in lipoproteins and cardiovascular risk factors play an important role in the progression of diabetic peripheral neuropathy (DPN). This systematic review aimed to estimate the predicting value of low-density lipoprotein (LDL) and systolic blood pressure (SBP) level in type-2 diabetes mellitus (T2DM) patients with and without peripheral neuropathy. We also tried to determine whether LDL and SBP are associated with an increased collision risk of DPN.

METHODS

A systematic search was conducted for eligible publications which explored the LDL and SBP level in T2DM patients with and without peripheral neuropathy. The quality of the included studies was assessed by the QUADAS-2 tool. The standardized mean difference (SMD) with 95% CI of LDL and SBP level were pooled to assess the correlation between LDL and SBP level with DPN. We performed random effects meta-regression analyses to investigate factors associated with an increased collision risk of DPN.

RESULTS

There was a significant association between LDL and SBP with poor prognosis of DPN in those included studies (I₂ = 88.1% and I₂ = 84.9%, respectively, Both P < 0.001). European T2DM patients have higher serum level of LDL in compare with the European DPN patients (SMD = 0.16, 95% CI: - 0.06 - 0.38; P < 0.001). SBP level was associated with a 2.6-fold decrease in non-DPN patients of T2DM (SMD = - 2.63, 95% CI: - 4.00 - -1.27, P < 0.001). Old age European T2DM patients have significantly high risk for diabetes drivers. Furthermore, the results of the case-control study design model are more precise to show the accuracy of SBP in Asian T2DM patients.

CONCLUSION

Our finding supports the LDL and SBP status could be associated with increased risk of peripheral neuropathy in T2DM patients.

Association Between Serum C-Peptide Level and Cardiovascular Autonomic Neuropathy According to Estimated Glomerular Filtration Rate in Individuals with Type 2 Diabetes

OBJECTIVE

To investigate the association between serum C-peptide level and cardiovascular autonomic neuropathy (CAN) in individuals with type 2 diabetes mellitus (DM) according to estimated glomerular filtration rate (eGFR) METHODS: In a cross-sectional study, we examined 939 individuals with type 2 DM. We measured fasting C-peptide, 2-hour postprandial C-peptide, and ΔC-peptide (postprandial C-peptide minus fasting C-peptide) levels. The individuals were classified into 2 groups based on eGFR: individuals without impaired renal function (eGFR ≥60 ml∙min^-1 1.73m^-2) and those with impaired renal function (eGFR <60 ml∙min^-1 1.73m^-2).

RESULTS

Individuals with CAN had lower fasting C-peptide, postprandial C-peptide, and ΔC-peptide levels in patients both with and without impaired renal function. Multivariate logistic regression analyses adjusted for gender, age, and other confounders, including eGFR, showed that serum C-peptide level was significantly associated with CAN (odds ratio [OR] per standard deviation increase in the log-transformed value, 0.67; 95% confidence interval [CI], 0.52-0.87 for fasting C-peptide, P < 0.01; OR, 0.62; 95% CI, 0.47-0.83 for postprandial C-peptide, P < 0.01; OR, 0.71; 95% CI, 0.54-0.93 for ΔC-peptide, P < 0.05).

CONCLUSIONS

Serum C-peptide level was negatively associated with CAN in individuals with type 2 DM independent of eGFR.

The dual effect of C-peptide on cellular activation and atherosclerosis: Protective or not?

C-peptide is a cleavage product of proinsulin that acts on different type of cells, such as blood and endothelial cells. C-peptide biological effects may be different in type 1 and type 2 diabetes. Besides, there are further evidence for a functional interaction between C-peptide and insulin. In this way, C-peptide has ambiguous effects, acting as an antithrombotic or thrombotic molecule, depending on the physiological environment and disease conditions. Moreover, C-peptide regulates interaction of leucocytes, erythrocytes, and platelets with the endothelium. The beneficial effects include stimulation of nitric oxide production with its subsequent release by platelets and endothelium, the interaction with erythrocytes leading to the generation of adenosine triphosphate, and inhibition of atherogenic cytokine release. The undesirable action of C-peptide includes the chemotaxis of monocytes, lymphocytes, and smooth muscle cells. Also, C-peptide was related with increased lipid deposits and elevated smooth muscle cells proliferation in the vessel wall, contributing to atherosclerosis. Purpose of this review is to explore these dual roles of C-peptide on the blood, contributing at one side to haemostasis and the other to atherosclerotic process.

Low serum phosphate and magnesium levels are associated with peripheral neuropathy in patients with type 2 diabetes mellitus

AIMS

To determine the relationship of serum phosphate, serum magnesium and peripheral nerve function in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 254 patients diagnosed with T2DM were included. Peripheral nerve function was evaluated by nerve conduction study with the use of electromyography. Composite z scores of conduction velocity, latency, and amplitude were constructed, respectively. Demographic, medical and laboratory data including serum phosphate and magnesium were collected.

RESULTS

Serum phosphate and serum magnesium levels were significantly lower in patients with diabetic peripheral neuropathy (DPN) (P < 0.01). And the percentages of DPN patients were lower in high tertile of serum phosphate and serum magnesium (P < 0.05). Furthermore, composite z score of conduction velocity (CV) (P = 0.012) were positively associated with serum phosphate levels and the composite z score of amplitude (P < 0.001) and CV (P = 0.041) were positively associated with serum magnesium levels. After adjusting potential related factors (age, gender, smoking, diabetes duration, body mass index, systolic blood pressure, glycated hemoglobin, total cholesterol, estimated glomerular filtration rate), serum levels of phosphate and magnesium were still related to status of DPN in logistic regression (P < 0.05).

CONCLUSION

Lower serum phosphate and magnesium significantly correlated with parameters of nerve conduction in T2DM patients. Serum phosphate and magnesium might underlie the pathophysiologic features of DPN.

Development of a double-antibody sandwich ELISA for rapid detection to C-peptide in human urine

C-peptide level is recognized as an important indicator of diabetes diagnosis. A sensitive and specific double-antibody sandwich enzyme-linked immunosorbent assay for the detection of C-peptide based on double antibody sandwich method was studied in this paper. The rabbit and hen were innunized with PLL-C-peptide and BSA-C-peptide respectively to obtain specific Yolk antibody (IgY) and polyclonal antibody used to construct the sandwich ELISA for the measurement of C-peptide. The limit of detection was 0.51 μg/mL and the half maximal inhibitory concentration (IC50) was 3.26 μg/mL. The method developed in the study showed no evident cross-reactivity with other similar analogs. The detection standard curve of C-peptide exhibited a good linearity (R² = 0.9896, n = 15). 17 types of the urine of diabetes patients on c-peptide levels compared with the hospital type of diabetes information, with a conclusion of a high consistent rate. Therefore, the methods could be selectively used for rapid screening of C-peptide in human urine, and the type of diabetes has some referential significance.

Association of glycaemic variability evaluated by continuous glucose monitoring with diabetic peripheral neuropathy in type 2 diabetic patients

PURPOSE

Diabetic peripheral neuropathy (DPN), a common microvascular complication of diabetes, is linked to glycaemic derangements. Glycaemic variability, as a pattern of glycaemic derangements, is a key risk factor for diabetic complications. We investigated the association of glycaemic variability with DPN in a large-scale sample of type 2 diabetic patients.

METHODS

In this cross-sectional study, we enrolled 982 type 2 diabetic patients who were screened for DPN and monitored by a continuous glucose monitoring (CGM) system between February 2011 and January 2017. Multiple glycaemic variability parameters, including the mean amplitude of glycaemic excursions (MAGE), mean of daily differences (MODD), standard deviation of glucose (SD), and 24-h mean glucose (24-h MG), were calculated from glucose profiles obtained from CGM. Other possible risks for DPN were also examined.

RESULTS

Of the recruited type 2 diabetic patients, 20.1% (n = 197) presented with DPN, and these patients also had a higher MAGE, MODD, SD, and 24-h MG than patients without DPN (p < 0.001). Using univariate and multiple logistic regression analyses, MAGE and conventional risks including diabetic duration, HOMA-IR, and hemoglobin A1c (HbA1c) were found to be independent contributors to DPN, and the corresponding odds ratios (95% confidence interval) were 4.57 (3.48-6.01), 1.10 (1.03-1.17), 1.24 (1.09-1.41), and 1.33 (1.15-1.53), respectively. Receiver operating characteristic analysis indicated that the optimal MAGE cutoff value for predicting DPN was 4.60 mmol/L; the corresponding sensitivity was 64.47%, and the specificity was 75.54%.

CONCLUSIONS

In addition to conventional risks including diabetic duration, HOMA-IR and HbA1c, increased glycaemic variability assessed by MAGE is a significant independent contributor to DPN in type 2 diabetic patients.

HbA1c variability and diabetic peripheral neuropathy in type 2 diabetic patients

BACKGROUND

Diabetic complications may be associated with impaired time-dependent glycemic control. Therefore, long-term glycemic variability, assessed by variations in haemoglobin A1c (HbA1c), may be a potential risk factor for microvascular complications, such as diabetic peripheral neuropathy (DPN). We investigated the association of HbA1c variability with DPN in patients with type 2 diabetes.

METHODS

In this cross-sectional study, 563 type 2 diabetic patients who had been screened for DPN and undergone quarterly HbA1c measurements during the year preceding enrolment were recruited. DPN was confirmed in patients displaying both clinical manifestations of neuropathy and abnormalities in a nerve conduction evaluation. HbA1c variability was assessed by the coefficient of variation of HbA1c (CV-HbA1c), and the mean of HbA1c (M-HbA1c) was calculated. In addition, medical history and clinical data were collected.

RESULTS

Among the recruited patients, 18.1% (n = 102) were found to have DPN, and these patients also presented with a higher CV-HbA1c than the patients without DPN (p < 0.001). The proportion of patients with DPN increased significantly from 6.9% in the first to 19.1% in the second and 28.5% in the third tertile of CV-HbA1c (p for trend < 0.001). After adjusting for initial HbA1c, M-HbA1c and other clinical factors via multiple logistic regression analysis, the odds ratios (ORs) for DPN in the second and third versus those in the first CV-HbA1c tertile were 3.61 (95% CI 1.62-8.04) and 6.48 (2.86-14.72), respectively. The area under the receiver operating characteristic (ROC) curve of CV-HbA1c was larger than that of M-HbA1c, at 0.711 (95% CI 0.659-0.763) and 0.662 (0.604-0.721), respectively. ROC analysis also revealed that the optimal cutoff value of CV-HbA1c to indicate DPN was 15.15%, and its corresponding sensitivity and specificity were 66.67% and 65.73%, respectively.

CONCLUSIONS

Increased HbA1c variability is closely associated with DPN in type 2 diabetic patients and could be considered as a potent indicator for DPN in these patients.