Glycated albumin and its variability as an indicator of cardiovascular autonomic neuropathy development in type 2 diabetic patients

Protein glycation in diabetes mellitus

Diabetes mellitus is the ninth leading cause of mortality worldwide. It is a complex disease that manifests as chronic hyperglycemia. Glucose exposure causes biochemical changes at the proteome level as reflected in accumulation of glycated proteins. A prominent example is hemoglobin A1c (HbA1c), a glycated protein widely accepted as a diabetic indicator. Another emerging biomarker is glycated albumin which has demonstrated utility in situations where HbA1c cannot be used. Other proteins undergo glycation as well thus impacting cellular function, transport and immune response. Accordingly, these glycated counterparts may serve as predictors for diabetic complications and thus warrant further inquiry. Fortunately, modern proteomics has provided unique analytic capability to enable improved and more comprehensive exploration of glycating agents and glycated proteins. This review broadly covers topics from epidemiology of diabetes to modern analytical tools such as mass spectrometry to facilitate a better understanding of diabetes pathophysiology. This serves as an attempt to connect clinically relevant questions with findings of recent proteomic studies to suggest future avenues of diabetes research.

Long-term HbA1c variability and macro-/micro-vascular complications in type 2 diabetes mellitus: a meta-analysis update

AIMS

The aim of the present study was to evaluate, by means of a meta-analysis approach, whether new available data, appeared on qualified literature, can support the effectiveness of an association of HbA1c variability with the risk of macro- and/or micro-vascular complications in type 2 diabetes mellitus (T2DM).

METHODS

The meta-analysis was conducted according to PRISMA Statement guidelines and considered published studies on T2DM, presenting HbA1c variability as standard deviation (SD) or its derived coefficient of variation (CV). Literature search was performed on PubMed in the time range 2015-July 2022, with no restrictions of language.

RESULTS

Twenty-three selected studies fulfilled the aims of the present investigation. Overall, the analysis of the risk as hazard ratios (HR) indicated a significant association between the HbA1c variability, expressed either as SD or CV, and the complications, except for neuropathy. Macro-vascular complications were all significantly associated with HbA1c variability, with HR 1.40 (95%CI 1.31-1.50, p < 0.0001) for stroke, 1.30 (95%CI 1.25-1.36, p < 0.0001) for transient ischaemic attack/coronary heart disease/myocardial infarction, and 1.32 (95%CI 1.13-1.56, p = 0.0007) for peripheral arterial disease. Micro-vascular complications yielded HR 1.29 (95%CI 1.22-1.36, p < 0.0001) for nephropathy, 1.03 (95%CI 0.99-1.08, p = 0.14) for neuropathy, and 1.15 (95%CI 1.08-1.24, p < 0.0001) for retinopathy. For all-cause mortality, HR was 1.33 (95%CI 1.27-1.39, p < 0.0001), and for cardiovascular mortality 1.25 (95%CI 1.17-1.34, p < 0.0001).

CONCLUSIONS

Our meta-analysis on HbA1c variability performed on the most recent published data since 2015 indicates positive association between HbA1c variability and macro-/micro-vascular complications, as well as mortality events, in T2DM, suggesting that this long-term glycaemic parameter merits further attention as a predictive, independent risk factor for T2DM population.

Glycated albumin and HbA1c as markers of lower extremity disease inUS adults with and without diabetes

AIM

We evaluated the associations of two biomarkers of hyperglycemia-hemoglobin A1c(HbA1c) and glycated albumin-with lower extremity disease in US adultsoverall and by diabetes status.

METHODS

We conducted a cross-sectional study of adult participants aged ≥ 40 years who attended the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (unweighted N = 5,785). We used logistic regression to evaluate the associations of HbA1c and glycated albumin with lower extremity disease: peripheral neuropathy (assessed by monofilament test), peripheral artery disease (assessed by ankle-brachial index), history of foot ulcer, or amputation. All analyses were weighted and accounted for the complex NHANES sample survey design.

RESULTS

The prevalence of lower extremity disease was 17.4% (15.9% in adults without diabetes and 33.2% in adults with diabetes). HbA1c and glycated albumin were not significantly associated with lower extremity disease in adults without diabetes. However, we observed significant associations of both HbA1c (OR 1.19 per 1-% point increase, 95 %CI 1.06-1.34) and glycated albumin (OR 1.06 per 1-% point increase, 95 %CI 1.02-1.10) with lower extremity disease in adults with diabetes after adjustment. The patterns of association were similar for HbA1c and glycated albumin (P-for-seemingly-unrelated-regression = 0.60), with strong linear associations observed at high (diabetic) levels of both biomarkers.

CONCLUSIONS

Our study suggests the importance of diabetes prevention and glycemic control in adults with diabetes to reduce the burden of lower extremity disease.

Cardiovascular autonomic neuropathy and incident diabetic kidney disease in patients with type 2 diabetes

AIMS

We investigated the association between cardiovascular autonomic neuropathy (CAN) and incident diabetic kidney disease (DKD).

METHODS

This retrospective longitudinal study included 2,033 patients with type 2 diabetes (mean age 57.2 years, 57.4% male, and median diabetes duration 8.0 years), free of renal dysfunction or cardiovascular disease at initiation. Cardiovascular autonomic reflex tests were performed once at baseline, and CAN was defined as ≥ 2 abnormal parasympathetic test results. Urine ACR and eGFR were concurrently measured at baseline and every 3-6 months thereafter. Incident DKD was defined as the development of ACR ≥ 30 mg/g at two or more follow-up examinations or eGFR < 60 ml/min/1.73 m² with ≥ 25% decrease from baseline.

RESULTS

During a median follow-up of 2.9 years (1.1 - 4.8), 290 (14.3%) patients developed DKD, comprising 79.7% (N = 231) cases of new-onset albuminuria alone, 14.5% (N = 42) cases of eGFR decline alone, and 5.8% (N = 17) cases of both. Compared to those without CAN, patients with CAN had a significantly higher risk of incident DKD in a multivariable Cox regression model (HR 1.56, 95% CI 1.15 - 2.12; P = 0.005).

CONCLUSION

CAN is may be a useful marker for long-term complications including DKD in patients with type 2 diabetes. Monitoring of CAN helps to identify high risk patients of future renal impairment.

Association between visit-to-visit variability of glycated albumin and diabetic retinopathy among patients with type 2 diabetes - A prospective cohort study

AIM

There is a paucity of studies regarding the association between long-term glycemic variability with the risk of diabetic retinopathy (DR) in patients with type 2 diabetes. Therefore, the purpose of this study is to explore the association of glycated albumin (GA) variability and HbA1c variability with the risk of DR in patients with type 2 diabetes.

METHODS

This prospective cohort study included 315 inpatients with type 2 diabetes (191 males and 124 females) with at least 3 measurements of GA and HbA1c within 2years prior to the baseline investigation. Different GA and HbA1c variability markers were calculated, including CV, variability independent of the mean (VIM), and the average real variability (ARV). Cox proportional hazard regression models were used to explore the association between visit-to-visit variability of GA and HbA1c and the risk of DR.

RESULTS

After an average follow-up of 3.42years, 81 patients developed incident DR. Multivariable-adjusted (diabetes duration, smoking status, systolic blood pressure, albumin to creatinine ratio, triglycerides, using fibrates, and mean HbA1c) hazard ratios of DR associated with each unit increase in GA-CV, GA-VIM, and GA-ARV were 1.05 (95% CI 1.02-1.09), 1.69 (95% CI 1.24-2.32), and 1.13 (95%CI 1.04-1.23), respectively. However, there was no significant association between visit-to-visit HbA1c variability and the risk of DR.

CONCLUSIONS

The present study indicated that visit-to-visit variability of GA can predict the risk of incident DR in patients with type 2 diabetes, and the prediction ability is independent of the average HbA1c levels.

Visit-to-visit variability of glycated albumin was associated with incidence or progression of lower extremity atherosclerotic disease

BACKGROUND

The aim of this study was to investigate the association of visit-to-visit variability of hemoglobin A1c (HbA1c) and glycated albumin (GA) with the risk of lower extremity atherosclerotic disease (LEAD).

METHOD

We performed a prospective cohort study of 436 patients with type 2 diabetes (258 men and 178 women) with at least 3 measurements of HbA1c and GA prior to baseline investigation from the Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital. Different HbA1c and GA variability markers were calculated. Multivariable Cox proportional hazard regression models were used to demonstrate the association between visit-to-visit HbA1c and GA variability and the risk of incident or progressive LEAD.

RESULTS

During a mean follow-up period of 3.77 years, 112 participants developed LEAD. Multivariate-adjusted hazard ratios (HRs) of LEAD across tertiles of GA-CV values were 1.00, 1.06 (95% confidence interval [CI] 0.65-1.75), and 1.71 (95% CI 1.07-2.73) (P for trend = 0.042), respectively. When we used GA-VIM and GA-ARV values as exposures, similar positive associations with the risk of LEAD primary were found. Multivariate-adjusted HRs of LEAD for each 1 unit increase in GA-CV, GA-VIM and GA-ARV were 1.03 (95% CI 1.01-1.06), 1.32 (95% CI 1.03-1.69), and 1.07 (95%CI 1.01-1.15), respectively. However, there was no significant association between visit-to-visit variability of HbA1c and the risk of LEAD.

CONCLUSIONS

Visit-to-visit variability of GA may be an optimal biomarker in relation to LEAD risk among patients with type 2 diabetes.

Diabetes mellitus in chronic kidney disease: Biomarkers beyond HbA1c to estimate glycemic control and diabetes-dependent morbidity and mortality

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). Optimal glycemic control contributes to improved outcomes in patients with DM, particularly for microvascular damage, but blood glucose levels are too variable to provide an accurate assessment and instead markers averaging long-term glycemic load are used. The most established glycemic biomarker of long-term glycemic control is HbA1c. Nevertheless, HbA1c has pitfalls that limit its accuracy to estimate glycemic control, including the presence of altered red blood cell survival, hemoglobin glycation and suboptimal performance of HbA1c assays. Alternative methods to evaluate glycemic control in patients with DM include glycated albumin, fructosamine, 1-5 anhydroglucitol, continuous glucose measurement, self-monitoring of blood glucose and random blood glucose concentration measurements. Accordingly, our aim was to review the advantages and pitfalls of these methods in the context of CKD.

Estimation of homeostatic dysregulation and frailty using biomarker variability: a principal component analysis of hemodialysis patients

Increased intraindividual variability in several biological parameters is associated with aspects of frailty and may reflect impaired physiological regulation. As frailty involves a cumulative decline in multiple physiological systems, we aimed to estimate the overall regulatory capacity by applying a principal component analysis to such variability. The variability of 20 blood-based parameters was evaluated as the log-transformed coefficient of variation (LCV) for one year’s worth of data from 580 hemodialysis patients. All the LCVs were positively correlated with each other and shared common characteristics. In a principal component analysis of 19 LCVs, the first principal component (PC1) explained 27.7% of the total variance, and the PC1 score exhibited consistent correlations with diverse negative health indicators, including diabetes, hypoalbuminemia, hyponatremia, and relative hypocreatininemia. The relationship between the PC1 score and frailty was subsequently examined in a subset of the subjects. The PC1 score was associated with the prevalence of frailty and was an independent predictor for frailty (odds ratio per SD: 2.31, P = 0.01) using a multivariate logistic regression model, which showed good discrimination (c-statistic: 0.85). Therefore, the PC1 score represents principal information shared by biomarker variabilities and is a reasonable measure of homeostatic dysregulation and frailty.

Evaluation of the relationship between cardiac autonomic function and glucose variability and HOMA-IR in prediabetes

AIMS

The present study aims to investigate the relationship between cardiac autonomic function (CAF) and glucose variability (GV) and HOMA-IR in subjects with prediabetes and normal glucose tolerance (NGT).

MATERIAL AND METHODS

Ninety-two subjects (59 with prediabetes and 33 with NGT), of mean age 50.3 ± 11.5 years, mean BMI 30.4 ± 6.0 kg/m², were included in this cross-sectional study. Glucose tolerance was assessed by OGTT according to WHO 2006 criteria. Glucose, HbA1c, insulin, oxLDL, and 3-Nitrotyrosine were measured. CGM was performed with a blinded sensor (FreeStyle Libre Pro). CAF was assessed by ANX-3.0 technology.

RESULTS

GV indices were increased in prediabetes. CAF was suppressed in subjects with any stage of dysglycemia. The prevalence of cardiac autonomic dysfunction was higher in prediabetes -20.3% as compared to NGT -3.0%, p = 0.028. HOMA-IR [OR 1.5 (95% CI: 1.1-2.1), p = 0.010] and time in target range [OR 0.8 (95% CI: 0.67-0.97), p = 0.021] were found to be predictive variables for impaired CAF. Sympathetic and parasympathetic activity negatively correlated with mean glycemia and GV indices and were independently related to JINDEX in prediabetes (F[1, 47] = 5.76, p = 0.021 and F[1, 47] = 5.94, p = 0.019, respectively); and to time above target range in NGT (F[1, 18] = 4.48, p = 0.049 and F[1, 18] = 4.65, p = 0.046, respectively).

CONCLUSION

CAF is declined in prediabetes and seems to be related to GV and HOMA-IR at early stages of dysglycemia.

Association between visit-to-visit variability of HbA1c and cognitive decline: a pooled analysis of two prospective population-based cohorts

AIMS/HYPOTHESIS

The aim of this study was to investigate the association between visit-to-visit variability in HbA_1c and cognitive function decline in the elderly population.

METHODS

We performed a pooled analysis of two prospective population-based cohorts (the Health Retirement Study [HRS] and the English Longitudinal Study of Ageing [ELSA]). Cognitive function, including memory and executive function, were assessed at baseline and every 2 years, while HbA_1c levels were assessed at baseline and every 4 years. Visit-to-visit variability (VVV) in HbA_1c was calculated using the CV, SD and variation independent of the mean (VIM) during the follow-up period. Linear mixed models were used to evaluate the association between HbA_1c variability and cognitive function decline with adjustment for demographics, mean HbA_1c, education, smoking, alcohol consumption, BMI, baseline hypertension, baseline diabetes status and HDL-cholesterol.

RESULTS

The study enrolled 6237 participants (58.23% women, mean age 63.38 ± 8.62 years) with at least three measurements of HbA_1c. The median follow-up duration was 10.56 ± 1.86 years. In the overall sample, compared with the lowest quartile of HbA_1c variability, participants in the highest quartile of HbA_1c variability had a significantly worse memory decline rate (-0.094 SD/year, 95% CI -0.185, -0.003) and executive function decline rate (-0.083 SD/year, 95% CI -0.125, -0.041), irrespective of mean HbA_1c values over time. Among individuals without diabetes, each 1-SD increment in HbA_1c CV was associated with a significantly higher rate of memory z score decline (-0.029, 95% CI -0.052, -0.005) and executive function z score decline (-0.049, 95% CI -0.079, -0.018) in the fully adjusted model.

CONCLUSIONS/INTERPRETATION

We observed a significant association between long-term HbA_1c variability and cognitive decline among the non-diabetic population in this study. The effect of maintaining steady glucose control on the rate of cognitive decline merits further investigation.

Continuous glucose monitoring defined glucose variability is associated with cardiovascular autonomic neuropathy in type 1 diabetes

BACKGROUND

The purpose of this study was to establish the association between continuous glucose monitoring (CGM)-defined glycaemic variability (GV) and cardiovascular autonomic neuropathy (CAN) in type 1 diabetes independent of mean glucose and to examine the relative contribution of each internationally standardized CGM parameter to this association.

MATERIALS AND METHODS

This study included 80 adults with type 1 diabetes who underwent 3-day CGM and autonomic function tests within 3 months. The degree of association between internationally standardized CGM parameters and CAN, defined as at least two abnormal parasympathetic tests or the presence of orthostatic hypotension, were analysed by logistic regression, receiver operating characteristics (ROC), and dominance analysis.

RESULTS

A total of 36 subjects (45.0%) were diagnosed with CAN. When adjusted with mean glucose and clinical risk factors of CAN, standard deviation, coefficient of variation, mean amplitude of glycaemic excursion, percent time in level 1 (glucose 54-69 mg/dL) and level 2 (glucose < 54 mg/dL) hypoglycaemia, area under the curve in level 2 hypoglycaemia, low blood glucose index, high blood glucose index, and percent time in glucose 70 to 180 mg/dL were independently associated with CAN. Multivariable ROC analysis and dominance analysis revealed the highest relative contribution of percent time in level 2 hypoglycaemia to the independent associations between CGM parameters and presence of CAN.

CONCLUSIONS

CGM-defined GV was associated with CAN independent of mean glucose in adults with type 1 diabetes. Among internationally standardized CGM parameters, those describing the degree of level 2 hypoglycaemia were the most significant contributors to this association.

Progression of cardiovascular autonomic neuropathy and cardiovascular disease in type 2 diabetes

BACKGROUND

To examine whether the progression rate of cardiovascular autonomic neuropathy (CAN) stage is an independent predictive factor for cardiovascular disease (CVD) in type 2 diabetes.

METHODS

Standardized cardiovascular autonomic reflex tests (CARTs) using traditional Ewing method were performed at baseline. The follow-up CARTs was recommended once every two years. We estimated the primary CVD endpoint, defined as coronary artery disease and ischemic stroke. The association between the progression rate of CAN stage and CVD was examined using time-dependent Cox proportional hazard models.

RESULTS

At baseline, 578 patients completed follow-up CARTs; the cohort comprised 329 women (56.9%) with a mean age of 58.3 ± 10.3 years and a mean diabetes duration of 10.1 ± 6.2 years. One hundred and seventy-six patients (30.4%) developed CAN progression between baseline and follow-up CARTs. In the multivariable Cox proportional hazards regression analysis, patients with CAN progression demonstrated a 3.32 times higher risk (95% confidence interval, CI 1.81-6.14, P < 0.001) of CVD than those without CAN progression. Patients who experienced CAN progression from the normal to definite stage had the greatest risk of CVD compared to other patients (hazard ratio 4.91, 95% CI 2.05-11.77, P for trend = 0.001).

CONCLUSIONS

CAN stage progression was associated with an increased risk of CVD in this type 2 diabetes cohort. Patients with rapid CAN progression had the greatest risk of CVD. Thus, regular screening and risk management of CAN progression is necessary to prevent CVD.

Visit-to-visit HbA1c variability is inversely related to baroreflex sensitivity independently of HbA1c value in type 2 diabetes

BACKGROUND

The relationship between long-term glycemic variability (GV) represented by visit-to-visit HbA1c variability and baroreflex sensitivity (BRS) in type 2 diabetes mellitus (T2DM) has not been clarified by previous literature. The present study is the first to examine the relationships between visit-to-visit HbA1c variability and BRS.

METHODS

This retrospective study initially analyzed data on 94 patients with T2DM. Visit-to-visit HbA1c variability was evaluated using the intrapersonal coefficient of variation (CV), standard deviation (SD), and adjusted SD of 8 or more serial measurements of HbA1c during a 2-year period. The BRS was analyzed using the sequence method. Short-term GV was assessed by measuring the glucose CV during 24-h continuous glucose monitoring (CGM). The primary objective was to determine if there was a relationship between visit-to-visit HbA1c variability (HbA1c CV) and BRS. Secondary objectives were to examine the relationship between other variables and BRS and the respective and combined effects of long-term GV (HbA1c CV) and short-term GV (CGM CV) on BRS.

RESULTS

A total of 57 patients (mean age 67.2 ± 7.7 years, mean HbA1c 7.3 ± 1.0%) who met this study's inclusion criteria were finally analyzed. In the univariate analysis, HbA1c CV (r = - 0.354, p = 0.007), HbA1c SD (r = - 0.384, p = 0.003), and adjusted HbA1c SD (r = - 0.391, p = 0.003) were significantly related to low levels of BRS. Multiple regression analysis showed that HbA1c CV, HbA1c SD, and adjusted HbA1c SD were inversely related to BRS. Furthermore, although the increase in either long-term GV (HbA1c CV) or short-term GV (CGM CV) as determined by 24-h CGM was inversely correlated with BRS, additional reductions in BRS were not shown in participants with both HbA1c CV and CGM CV values above the median.

CONCLUSIONS

Visit-to-visit HbA1c variability was inversely related to BRS independently of the mean HbA1c in patients with T2DM. Therefore, visit-to-visit HbA1c variability might be a marker of reduced BRS in T2DM.

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.

Glycemic variability in continuous glucose monitoring is inversely associated with baroreflex sensitivity in type 2 diabetes: a preliminary report

Background

It is presently unclear whether glycemic variability (GV) is associated with baroreflex sensitivity (BRS), which is an early indicator of cardiovascular autonomic neuropathy. The present study is the first to examine the relationships between BRS and GV measured using continuous glucose monitoring (CGM).

Methods

This was a multicenter, prospective, open-label clinical trial. A total of 102 patients with type 2 diabetes were consecutively recruited for this study. GV was assessed by measuring the standard deviation (SD), glucose coefficient of variation (CV), and the mean amplitude of glycemic excursions (MAGE) during CGM. The BRS was analyzed from electrocardiogram and blood pressure recordings using the sequence method on the first day of hospitalization.

Results

A total of 94 patients (mean diabetes duration 9.7 ± 9.6 years, mean HbA1c 61.0 ± 16.8 mmol/mol [7.7 ± 1.5%]) were analyzed. In the univariate analysis, CGM-SD (r = − 0.375, p = 0.000), CGM-CV (r = − 0.386, p = 0.000), and MAGE (r = − 0.395, p = 0.000) were inversely related to BRS. In addition to GV, the level of BRS correlated with the coefficient of variation in the R–R intervals (CVR-R) (r = 0.520, p = 0.000), heart rate (HR) (r = − 0.310, p = 0.002), cardio-ankle vascular index (CAVI) (r = − 0.326, p = 0.001), age (r = − 0.519, p = 0.000), and estimated glomerular filtration rate (eGFR) (r = 0.276, p = 0.007). Multiple regression analysis showed that CGM-CV and MAGE were significantly related to a decrease in BRS. These findings remained after adjusting the BRS for age, sex, hypertension, dyslipidemia, HR, eGFR, CAVI, and CGM-mean glucose. Additionally, BRS was divided according to quartiles of the duration of diabetes (Q1–4). BRS decreased after a 2-year duration of diabetes independently of age and sex.

Conclusions

GV was inversely related to BRS independently of blood glucose levels in type 2 diabetic patients. Measurement of BRS may have the potential to predict CV events in consideration of GV.

Trial registration UMIN Clinical Trials Registry UMIN000025964, 28/02/2017

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0683-2) contains supplementary material, which is available to authorized users.

Long-term visit-to-visit glycemic variability as predictor of micro- and macrovascular complications in patients with type 2 diabetes: The Rio de Janeiro Type 2 Diabetes Cohort Study

Background

Long-term visit-to-visit glycemic variability is an additional measure of glycemic control. We aimed to evaluate the prognostic value of several measures of glycemic variability for the occurrence of micro- and macrovascular complications, and all-cause mortality in patients with type 2 diabetes.

Methods

654 individuals were followed-up over a median of 9.3 years. Glycemic variability (SDs and coefficients of variation of HbA_1c and fasting glycaemia) was measured during the first 12- and 24-months. Multivariate Cox analysis, adjusted for risk factors and mean HbA_1c and fasting glycaemia levels, examined the associations between glycemic variability and the occurrence of microvascular (retinopathy, microalbuminuria, renal function deterioration, peripheral neuropathy) and macrovascular complications [total cardiovascular events (CVE), major adverse CVEs (MACE) and cardiovascular mortality], and of all-cause mortality.

Results

During follow-up, 128 patients had a CVE (96 MACE), and 158 patients died (67 from cardiovascular diseases); 152 newly-developed or worsened diabetic retinopathy, 183 achieved the renal composite outcome (89 newly developed microalbuminuria and 91 deteriorated renal function), and 96 newly-developed or worsened peripheral neuropathy. Glycemic variability, particularly the 24-month parameters either estimated by HbA_1c or by fasting glycemia, predicted all endpoints, except for retinopathy and peripheral neuropathy development/progression, and was a better predictor than mean HbA_1c. Glycemic variability predicted retinopathy development/progression in patients with good glycemic control (HbA_1c ≤ 7.5%, 58 mmol/mol) and predicted new-incident peripheral neuropathy.

Conclusions

Long-term visit-to-visit glycemic variability is an additional and frequently a better glycemic parameter than mean HbA_1c levels for assessing the risk of future development of micro- and macrovascular complications in patients with type 2 diabetes.

Postload Glycated Albumin as an Alternate Measure for Diabetes Screening in a Chinese Population

In previous epidemiological screening in China, glycated albumin (GA) was mostly detected during the fasting state. This strict restriction causes some problems with diabetes screening. It is unclear if GA could help improve the efficiency of screening for diabetes for subjects who are not in the fasting state. The present study analyzed the differences between fasting and postload (30, 60, 120, and 180 min) GA levels. A total of 691 participants were enrolled in the present study. The Bland-Altman difference plots revealed that 95.4, 94.8, 93.6, and 93.9% of data points were within the limits of agreement for each time point. The receiver operating characteristic curve showed that the areas under the curve (AUC) for baseline GA and postload GA for every time point were 0.822 (95% CI 0.791-0.849), 0.821 (95% CI 0.790-0.848), 0.833 (95% CI 0.803-0.860), 0.840 (95% CI 0.811-0.867), and 0.840 (95% CI 0.810-0.867), with sensitivities of 67.5, 68.1, 69.3, 71.6, and 69.3%, respectively. There was no difference between the baseline and postload GA levels in either AUC or sensitivity (all p > 0.05). In conclusion, postload serum GA levels were in good agreement with those at baseline, and thus, it may be reasonable to employ nonfasting measurements of GA levels for diabetes screening.