HbA(1c) variability and the development of microalbuminuria in type 2 diabetes: Tsukuba Kawai Diabetes Registry 2

Prognostic value of longitudinal HbA1c variability in predicting the development of diabetic sensorimotor polyneuropathy among patients with type 2 diabetes mellitus: A prospective cohort observational study

AIMS/INTRODUCTION

This prospective cohort study aims to identify the optimal measure of glycated hemoglobin (HbA1c) variability and to explore its relationship with the development of new diabetic sensorimotor polyneuropathy (DSPN) in individuals with type 2 diabetes mellitus, building upon previous cross-sectional studies that highlighted a significant association between HbA1c visit-to-visit variability and DSPN.

MATERIALS AND METHODS

In a prospective study, 321 participants diagnosed with type 2 diabetes mellitus underwent comprehensive clinical assessments, neurophysiologic studies, and laboratory evaluations at enrollment and follow-up. Various indices, including HbA1c standard deviation (HbA1c SD), coefficient of variation (HbA1c CV), HbA1c change score (HbA1c HVS), and average real variability (HbA1c ARV), were employed to calculate the visit-to-visit variability HbA1c based on 3 month intervals. The investigation focused on examining the associations between these indices and the development of new DSPN.

RESULTS

The average follow-up duration was 16.9 ± 6.9 months. The Cox proportional hazards model identified age (P = 0.001), diabetes duration (P = 0.024), and HbA1C ARV (P = 0.031) as the sole factors associated with the development of new DSPN. Furthermore, the cumulative risk of developing DSPN over 1 year demonstrated a significant association with HbA1C ARV (P = 0.03, log-rank test).

CONCLUSIONS

Apart from age and diabetes duration, HbA1c variability emerged as a robust predictor for the occurrence of new DSPN. Among the various measures of HbA1c variability evaluated, HbA1c ARV demonstrated the highest potential as a reliable indicator for anticipating the onset of new DSPN.

Glycated hemoglobin variability and the risk of cardiovascular events in patients with prediabetes and type 2 diabetes mellitus: A post-hoc analysis of a prospective and multicenter study

AIMS/INTRODUCTION

High glycated hemoglobin (HbA1c) variability has been reported to be linked with cardiovascular events in type 2 diabetes patients. Only a few studies have been carried out on Asian patients. This study aimed to investigate the association of prediabetes and type 2 diabetes in Asian patients by performing a post-hoc analysis of a multicenter, prospective, observational study.

MATERIALS AND METHODS

Data for prediabetes and type 2 diabetes patients were retrieved from a multicenter national registry entitled "CORE-Thailand study." The primary outcome was 4P-MACE (major adverse cardiovascular events, including non-fatal myocardial infarction, heart failure hospitalization, non-fatal stroke and all-cause death). Patients were stratified according to quartiles of HbA1c standard deviation. The Cox proportional hazards regression model was used to estimate the association of HbA1c variability with incident cardiovascular disease.

RESULTS

A total of 3,811 patients with prediabetes and type 2 diabetes were included. The median follow-up duration was 54 months. In the fully adjusted model, the highest quartile of HbA1c variability showed a statistically significant association with 4P-MACE (hazard ratio [HR] 2.77, 95% confidence interval [CI] 1.77-4.35), fatal and non-fatal myocardial infarction (HR 6.91, 95% CI 1.90-25.12), hospitalization for heart failure (HR 3.34, 95% CI 1.20-9.26) and all-cause death (HR 3.10, 95% CI 1.72-5.57). All these outcomes were statistically significantly different among four quartiles of HbA1c (log-rank P-value <0.05). Fatal and non-fatal stroke showed no statistically significant association with high HbA1c variability.

CONCLUSION

High HbA1c variability in the highest quartile showed a statistically significant association with multiple adverse cardiovascular events in an Asian population. Minimizing HbA1c fluctuation during long-term follow up should be another important objective for type 2 diabetes patients.

Long-term Visit-to-Visit Variability in Hemoglobin A1c and Kidney-Related Outcomes in Persons With Diabetes

RATIONALE & OBJECTIVE

To characterize associations between long-term visit-to-visit variability of hemoglobin A1c (HbA1c) and risk of adverse kidney outcomes in patients with diabetes.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

93,598 adults with diabetes undergoing routine care in Stockholm, Sweden.

EXPOSURES AND PREDICTORS

Categories of baseline and time-varying HbA1c variability score (HVS, the percentage of total HbA1c measures that vary by>0.5% [5.5mmol/mol] during a 3-year window): 0-20%, 21%-40%, 41%-60%, 61%-80%, and 81%-100%, with 0-20% as the reference group.

OUTCOME

Chronic kidney disease (CKD) progression (composite of>50% estimated glomerular filtration rate [eGFR] decline and kidney failure), acute kidney disease (AKI by clinical diagnosis or transient creatinine elevations according to KDIGO criteria), and worsening of albuminuria.

ANALYTICAL APPROACH

Multivariable Cox proportional hazards regression.

RESULTS

Compared with persons showing low HbA1c variability (HVS 0-20%), any increase in variability was associated with a higher risk of adverse kidney outcomes beyond mean HbA1c. For example, for patients with a baseline HbA1c variability of 81%-100%, the adjusted HR was 1.6 (95% CI, 1.47-1.74) for CKD progression, 1.23 [1.16-1.3] for AKI, and 1.28 [1.21-1.36] for worsening of albuminuria. The results were consistent across subgroups (diabetes subtypes, baseline eGFR, or albuminuria categories), in time-varying analyses and in sensitivity analyses including time-weighted average HbA1c or alternative metrics of variability.

LIMITATIONS

Observational study, limitations of claims data, lack of information on diet, body mass index, medication changes, and diabetes duration.

CONCLUSIONS

Higher long-term visit-to-visit HbA1c variability is consistently associated with the risks of CKD progression, AKI, and worsening of albuminuria.

PLAIN-LANGUAGE SUMMARY

The evidence for current guideline recommendations derives from clinical trials that focus on a single HbA1c as the definitive measure of efficacy of an intervention. However, long-term visit-to-visit fluctuations of HbA1c may provide additional value in the prediction of future kidney complications. We evaluated the long-term fluctuations in glycemic control in almost 100,000 persons with diabetes undergoing routine care in Stockholm, Sweden. We observed that higher long-term HbA1c fluctuation is consistently associated with the risks of chronic kidney disease progression, worsening of albuminuria and acute kidney injury. This finding supports a role for long-term glycemic variability in the development of kidney complications and illustrates the potential usefulness of this metric for risk stratification at the bedside beyond a single HbA1c test.

Within-subject variation of HbA1c: A systematic review and meta-analysis

BACKGROUND

Glycosylated haemoglobin (HbA1c) measurement is used to diagnose and to guide treatment of diabetes mellitus. Within-subject variability in measured HbA1c affects its clinical utility and interpretation, but no comprehensive systematic review has described within-subject variability.

METHODS

A systematic review and meta-analysis was performed of within-subject variability of HbA1c. Multiple databases were searched from inception to November 2022 for follow-up studies of any design in adults or children, with repeated measures of HbA1c or glycosylated haemoglobin. Title and abstract screening was performed in duplicate, full text screening and data extraction by one reviewer and verified by a second. Risk of bias of included papers was assessed using a modified consensus-based standards for the selection of health measurement Instruments (COSMIN) tool. Intraclass correlation coefficient (ICC) results were pooled with a meta-analysis and coefficient of variation (CV) results were described by median and range.

RESULTS

Of 2675 studies identified, 111 met the inclusion criteria. Twenty-five studies reported variability data in healthy patients, 19 in patients with type 1 diabetes and 59 in patients with type 2 diabetes. Median within-subject coefficient of variation (CV) was 0.070 (IQR 0.034 to .09). For healthy subjects the median CV for HbA1c % was 0.017 (IQR 0.013 to 0.022), for patients with type 1 diabetes 0.084 (IQR 0.067 to 0.89) and for type 2 diabetes 0.083 (IQR 0.06 to 0.10). CV increased with mean population HbA1c.

LIMITATIONS

Assessment of variability was not the main aim of many of the included studies and some relevant papers may have been missed. Many included papers had few participants or few repeated measurements.

CONCLUSIONS

Within-subject variability of HbA1c is higher for patients with than without diabetes and increases with mean population HbA1c. This may confound observed relationships between HbA1c variability and health outcomes. Because of its importance in clinical decision-making there is a need for better estimates and understanding of factors associated with of HbA1c variability.

Association of fasting blood glucose variability with all-cause mortality in heart transplant recipients

BACKGROUND

Fasting blood glucose (FBG) variability, an emerging marker of glycemic control, has been shown to be related to the risk of cardiovascular events and all-cause mortality in subjects with or without diabetes. However, whether FBG variability is independently associated with a higher all-cause mortality in heart transplant recipients remains unknown.

METHODS

We performed a retrospective cohort study including 373 adult recipients who survived for at least 1 year after heart transplantation with a functioning graft and measured FBG more than three times within first year after transplantation. Multivariable adjusted Cox regression analyses were performed to assess the association between FBG variability and all-cause mortality.

RESULTS

Patients were categorized into three groups according to the coefficient of variation of FBG level: ≤7.0%, 7.0%-13.5%, and >13.5%. During a median follow-up of 44.4 months (interquartile range [IQR], 22.6-63.3 months), 31 (8.3%) participants died. In univariate analyses, FBG variability was associated with an increased all-cause mortality (hazard ratio [HR]: 3.00, 95% confidence interval [CI]: 1.67, 5.38; p < .001). This association remained materially unchanged in the multivariable model adjusted for components of demographics, cardiovascular history and lifestyle, hospital information, immunosuppressive therapy, and post-transplant renal function (HR: 2.75, 95% CI: 1.43, 5.28; p = .004).

CONCLUSIONS

After heart transplantation, high FBG variability is strongly and independently associated with an increased risk of all-cause mortality. Our findings suggest that FBG variability is a novel risk factor and prognostic marker for heart transplantation recipients in outpatient clinic.

Relationship between Diabetic Nephropathy and Development of Diabetic Macular Edema in Addition to Diabetic Retinopathy

This study aimed to examine the relationship between diabetic retinopathy (DR) and systemic factors. We evaluated 261 patients (143 men, 118 women, aged 70.1 ± 10.1 years) with type 2 diabetes. All participants underwent a fundus examination, fundus photography using spectral domain optical coherence tomography (SD-OCT), and blood tests. For glycated hemoglobin (HbA1c) levels, the average and highest values in the past were used. We observed DR in 127 (70 men and 57 women) of 261 patients. Logistic regression analyses revealed a significant correlation between DR development and the duration of diabetes (OR = 2.40; 95% CI: 1.50), average HbA1c level (OR = 5.57; 95% CI: 1.27, 24.4), highest HbA1c level (OR = 2.46; 95% CI: 1.12, 5.38), and grade of diabetic nephropathy (DN) (OR = 6.23; 95% CI: 2.70, 14.4). Regression analyses revealed a significant correlation between the severity of DR and duration of diabetes (t = -6.66; 95% CI: 0.21, 0.39), average HbA1c level (t = 2.59; 95% CI: 0.14, 1.02), and severity of DN (t = 6.10; 95% CI: 0.49, 0.97). Logistic regression analyses revealed a significant correlation between diabetic macular edema (DME) development and DN grade (OR = 2.22; 95% CI: 1.33, 3.69). DN grade correlates with the development of DR and DME, and decreased renal function predicts the onset of DR.

Joint effect of blood pressure and glycemic variation on the risk of cardiovascular morbidity and mortality in persons with type 2 diabetes

OBJECTIVE

Few studies have explored the association of visit-to-visit variation in blood pressure (BP) and glycemic factors with cardiovascular disease (CVD) morbidity and mortality. This study aimed to examine the independent and joint effect of visit-to-visit BP and glycemic variation on CVD morbidity and mortality in persons with T2DM.

METHODS

The present study consisted of two retrospective cohort studies. The Taiwan Diabetes Study was based on a database of the National Diabetes Care Management Program (DCMP) and linked with cardiovascular morbidity incidence. The Taichung Diabetes Study was based on the DCMP database of a medical center, which can be linked with the National Death Registry dataset. The outcomes were analyzed by using Cox's proportional hazard models.

RESULTS

A total of 13,280 and 10,894 persons with T2DM in Taiwan and Taichung Diabetes Study, respectively, were included. SBP-CV, FPG-CV, and HbA1c-CV were significant predictors of stroke, CVD event or death, all-cause mortality, and expanded CVD mortality, whereas DBP-CV was a significant predictor of all-cause mortality and expanded and non-expanded CVD mortality. The joint effect of SBP, FPG, and HbA1c predicted the incidence of stroke and CVD event or death with increased risks of 16 %-35 %. In addition, the joint effect of SBP, DBP, FPG, and HbA1c was associated with all-cause and expanded CVD mortality with increased risks of 29 %-81 %.

CONCLUSIONS

The joint effect of BP and glucose variation improved the prediction of cardiovascular morbidity and mortality. Moreover, simultaneous measurement of visit-to-visit BP and glycemic variation may stratify persons with cardiovascular risks and may be regarded as important therapeutic goals in the care of T2DM.

Mean HbA1c and HbA1c variability are associated with differing diabetes-related complications in patients with type 2 diabetes mellitus

AIMS

To study the different effects of mean HbA1c and HbA1c variability on diabetes-related complications in patients with type 2 diabetes mellitus.

METHODS

1869 patients with type 2 diabetes were followed-up for a median of 9.5 years in a Diabetes Shared Care Program. Mean HbA1c (HbA1c-mean) and standard deviation of HbA1c (HbA1c-SD) were calculated during the first 5 years. The clinical outcomes included nephropathy (urine albumin-to-creatinine ratio [UACR] > 300 mg/g and doubling of serum creatinine), retinopathy (any and advanced), and mortality (due to all-causes, and cardiovascular disease [CVD]).

RESULTS

HbA1c-mean was independently associated with UACR > 300 mg/g (Hazard ratio [HR] 1.308 [95% confidence interval {CI}, 1.194-1.433]), any retinopathy (HR 1.274 [1.171-1.385]), and advanced retinopathy (HR 1.237 [1.014-1.509]). HbA1c-SD was independently associated with UACR > 300 mg/g (HR 1.478 [1.189-1.837]), doubling of serum creatinine (HR 2.133 [1.470-3.095]), all-cause mortality (HR 1.880 [1.561-2.266]), and CVD mortality (HR 1.431 [1.069-1.915]). Receiver operating characteristic (ROC) curves showed HbA1c-mean was more associated with any retinopathy, whereas HbA1c-SD was more associated with doubling of serum creatinine, all-cause and CVD mortality.

CONCLUSION

Both HbA1c-mean and HbA1c-SD predicted most diabetes-related complications in patients with type 2 diabetes. However, HbA1c-mean was more effective at predicting retinopathy, while HbA1c-SD was more effective at predicting deterioration of renal function and increased mortality.

The Scope of HbA1c Variability and Risk of Vascular Complications Among Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Prospective Studies

Glycated hemoglobin (HbA1c) variability is emerging as an indicator of long-term glycemic control, which may play a significant role during vascular complications. We conducted a systematic review and meta-analysis to assess the association between the scope of HbA1c variability and vascular complications in patients with type 2 diabetes mellitus. PubMed and Embase were searched for studies that evaluated the association of HbA1c variability with vascular complications in patients with type 2 diabetes. Two reviewers independently completed data extraction. Random-effects meta-analysis was conducted with stratification according to the type of vascular complications. Nine studies were eligible for inclusion in our systematic review and meta-analysis. Six studies evaluated the impact of the standard deviation of HbA1c (HbA1c-SD) on cardiovascular events and showed an association of HbA1c-SD with cardiovascular events (HR: 1.25, 95% CI 1.18-1.32, 5 studies). Six studies evaluated renal disease associated with HbA1c-SD and showed that HbA1c-SD was correlated with an increased risk of renal disease (HR: 1.19, 95% CI 1.13-1.24). Two studies evaluated HbA1c-SD and the risk of retinopathy and showed that no significant association was found between retinopathy and HbA1c-SD (HR 1.08, 95% CI 0.92-125). For HbA1c-SD ranging from 0.6 to 0.8%, HbA1c-SD was associated with an increased risk of cardiovascular events (HR: 1.25, 95% CI 1.15-1.35) and renal disease (HR: 1.16, 95% CI 1.11-1.22). For individuals with index HbA1c variability greater than or equal to 0.6%, HbA1c variability was significantly associated with vascular complications in patients with type 2 diabetes mellitus.

Predictive Ability of Visit-to-Visit Variability of HbA1c Measurements for the Development of Diabetic Kidney Disease: A Retrospective Longitudinal Observational Study

AIMS

This study is aimed at clarifying the relationship between visit-to-visit variability of glycated hemoglobin (HbA1c) and the risk of diabetic kidney disease (DKD) and to identifying the most useful index of visit-to-visit variability of HbA1c.

METHODS

This clinic-based retrospective longitudinal study included 699 Japanese type 2 diabetes mellitus patients. Visit-to-visit variability of HbA1c was calculated as the internal standard deviation of HbA1c (HbA1c-SD), the coefficient of variation of HbA1c (HbA1c-CV), the HbA1c change score (HbA1c-HVS), and the area under the HbA1c curve (HbA1c-AUC) with 3-year serial HbA1c measurement data, and the associations between these indices and the development/progression of DKD were examined.

RESULTS

Cox proportional hazards models showed that the HbA1c-SD and HbA1c-AUC were associated with the incidence of microalbuminuria, independently of the HbA1c level. These results were verified and replicated in propensity score (PS) matching and bootstrap analyses. Moreover, the HbA1c-SD and HbA1c-AUC were also associated with oxidized human serum albumin (HSA), an oxidative stress marker.

CONCLUSIONS

Visit-to-visit variability of HbA1c was an independent risk factor of microalbuminuria in association with oxidative stress among type 2 diabetes mellitus patients. HbA1c-AUC, a novel index of HbA1c variability, may be a potent prognostic indicator in predicting the risk of microalbuminuria.

The Frequency and Determinants of HbA1c Variability in Type 2 Diabetic Patients

Aim: Glycated hemoglobin (HbA1c) is an efficient and easy test to evaluate glycemic control of patients with type 2 diabetes (T2DM). This study aims to evaluate HbA1c variability and associated factors in patients with T2DM. Methods: Four hundred four consecutive patients with T2DM who gave consent to participate and who were eligible were included. The inclusion criterion was presence of three or more HbA1c levels in 1 year. A change ≥0.5% in HbA1c was identified as a significant variability in HbA1c in 1 year. Primary endpoint of the study was to identify the factors associated with HbA1c variability. Patients were grouped as (1) without variability, (2) one variability, and (3) more than one variability. Variability frequency and associated factors such as body mass index, smoking, and c-peptide value were assessed. Results: There were 404 patients (45.3% male) with mean age 58.91 ± 10.8 years. Thirty-four patients (8.4%) had no variability, 19 patients (4.7%) had one variability, and 351 patients (86.9%) had more than one variability. Patients only on insulin treatment and patients on both oral antidiabetic agents (OAD) and insulin had higher variability than patients only on OAD (P = 0.002; P < 0.01). Patients with variability had higher HbA1c levels than patients without variability (P < 0.01). A 1% increase in HbA1c had a 4.864-fold (95% confidence interval: 2.360-10.023) increased variability risk. Conclusions: HbA1c variability is seen in 9 of 10 patients with T2DM and higher HbA1c values and poor glycemic control are associated with a higher risk of HbA1c variability.

Fasting Glucose Variation Predicts Microvascular Risk in ACCORD and VADT

AIMS

The association of glycemic variability with microvascular disease complications in type 2 diabetes (T2D) has been under-studied and remains unclear. We investigated this relationship using both Action to Control Cardiovascular Risk in Diabetes (ACCORD) and the Veteran Affairs Diabetes Trial (VADT).

METHODS

In ACCORD, fasting plasma glucose (FPG) was measured 1 to 3 times/year for up to 84 months in 10 251 individuals. In the VADT, FPG was measured every 3 months for up to 87 months in 1791 individuals. Variability measures included coefficient of variation (CV) and average real variability (ARV) for fasting glucose. The primary composite outcome was time to either severe nephropathy or retinopathy event and secondary outcomes included each outcome individually. To assess the association, we considered variability measures as time-dependent covariates in Cox proportional hazard models. We conducted a meta-analysis across the 2 trials to estimate the risk of fasting glucose variability as well as to assess the heterogenous effects of FPG variability across treatment arms.

RESULTS

In both ACCORD and the VADT, the CV and ARV of FPG were associated with development of future microvascular outcomes even after adjusting for other risk factors, including measures of average glycemic control (ie, cumulative average of HbA1c). Meta-analyses of these 2 trials confirmed these findings and indicated FPG variation may be more harmful in those with less intensive glucose control.

CONCLUSIONS

This post hoc analysis indicates that variability of FPG plays a role in, and/or is an independent and readily available marker of, development of microvascular complications in T2D.

Glycemic Variability, Oxidative Stress, and Impact on Complications Related to Type 2 Diabetes Mellitus

Chronic hyperglycemia is an established risk factor for the development of complications in both type 1 and type 2 diabetes, but glycemic variability has emerged as a possible independent risk factor for diabetes complications, possibly through oxidative stress. In this review, methods to access glycemic variability and oxidative stress, as well as their correlations, are discussed. Non-pharmacological and pharmacological strategies are also debated to achieve better glycemic control, not only by HbA1c target but also with reduced glycemic fluctuations, possibly minimizing the risk of diabetes complications.

Long-Term Glycemic Variability and Vascular Complications in Type 2 Diabetes: Post Hoc Analysis of the FIELD Study

AIMS

To investigate whether long-term glycemic variability (GV) is associated with vascular complication development in type 2 diabetes.

METHODS

In a post hoc FIELD trial analysis, GV was calculated as the standard deviation and coefficient of variation (CV) of glycated hemoglobin A1c (HbA1c) and fasting plasma glucose. Baseline variables were compared across quartiles of on-study variability by chi square and ANOVA. Prospective associations between baseline to 2-year GV and subsequent vascular and mortality outcomes were analyzed using landmark logistic and Cox proportional hazards regression.

RESULTS

Baseline factors associated with higher on-study GV included younger age, male gender, longer diabetes duration, and higher pharmacological therapies usage. Both HbA1c and fasting glucose CV were associated with increased risk of microvascular complications (HR 1.02 [95% CI, 1.01-1.03] P < 0.01; and HR 1.01 [95% CI, 1.00-1.01] P < 0.001, respectively). HbA1c and fasting glucose CV were associated with increased cardiovascular disease (HR 1.02 [95% CI, 1.00-1.04]; and HR 1.01 [95% CI, 1.00-1.02], both P < 0.05). HbA1c CV associated with increased stroke (HR 1.03 [95% CI, 1.01-1.06) P < 0.01). Glucose CV associated with increased coronary events (HR 1.01 [95% CI, 1.00-1.02] P < 0.05). Both HbA1c and glucose CV associated with increased total mortality (HR 1.04 [95% CI, 1.02-1.06]; and HR 1.01 [95% CI, 1.01-1.02], both P < 0.001) and noncardiovascular mortality (HR 1.05 [95% CI, (1.03-1.07]; and HR 1.02 [95% CI, 1.01-1.03], both P < 0.001). HbA1c CV associated with coronary mortality (HR 1.04 [95% CI, 1.01-1.07] P < 0.05).

CONCLUSIONS

Long-term GV was associated with increased risk of vascular outcomes in type 2 diabetes.

Single snapshot spatial frequency domain imaging for risk stratification of diabetes and diabetic foot

Diabetic foot is one of the major complications of diabetes. In this work, a real-time Single Snapshot Multiple-frequency Demodulation (SSMD) - Spatial Frequency Domain Imaging (SFDI) system was used to image the forefoot of healthy volunteers, diabetes, and diabetic foot patients. A layered skin model was used to obtain the 2D maps of optical and physiological parameters, including cutaneous hemoglobin concentration, oxygen saturation, scattering properties, melanin content, and epidermal thickness, from every single snapshot. We observed a strong correlation between the measured optical and physiological parameters and the degree of diabetes. The cutaneous hemoglobin concentration, oxygen saturation, and epidermal thickness decrease, whereas the melanin content increases with the progress of diabetes. The melanin content further increases, and the reduced scattering coefficient and scattering power are lower for diabetic foot patients than those of both healthy and diabetic subjects. High accuracies (AUC) of 97.2% (distinguishing the diabetic foot patients among all subjects), 95.2% (separating healthy subjects from the diabetes patients), and 87.8% (classifying mild vs severe diabetes), respectively, are achieved in binary classifications in sequence using the SSMD-SFDI system, demonstrating its applicability to risk stratification of diabetes and diabetic foot. The prognostic value of the SSMD-SFDI system in the prediction of the occurrence of the diabetic foot and other applications in monitoring tissue microcirculation and peripheral vascular disease are also addressed.

Comparative predictive ability of visit-to-visit HbA1c variability measures for microvascular disease risk in type 2 diabetes

BACKGROUND

To assess the associations of various HbA1c measures, including a single baseline HbA1c value, overall mean, yearly updated means, standard deviation (HbA1c-SD), coefficient of variation (HbA1c-CV), and HbA1c variability score (HVS), with microvascular disease (MVD) risk in patients with type 2 diabetes.

METHODS

Linked data between National Cheng Kung University Hospital and Taiwan's National Health Insurance Research Database were utilized to identify the study cohort. The primary outcome was the composite MVD events (retinopathy, nephropathy, or neuropathy) occurring during the study follow-up. Cox model analyses were performed to assess the associations between HbA1c measures and MVD risk, with adjustment for patients' baseline HbA1c, demographics, comorbidities/complications, and treatments.

RESULTS

In the models without adjustment for baseline HbA1c, all HbA1c variability and mean measures were significantly associated with MVD risk, except HVS. With adjustment for baseline HbA1c, HbA1c-CV had the strongest association with MVD risk. For every unit of increase in HbA1c-CV, the MVD risk significantly increased by 3.42- and 2.81-fold based on the models without and with adjustment for baseline HbA1c, respectively. The associations of HbA1c variability and mean measures with MVD risk in patients with baseline HbA1c < 7.5% (58 mmol/mol) were stronger compared with those in patients with baseline HbA1c ≥ 7.5% (58 mmol/mol).

CONCLUSIONS

HbA1c variability, especially HbA1c-CV, can supplement conventional baseline HbA1c measure for explaining MVD risk. HbA1c variability may play a greater role in MVD outcomes among patients with relatively optimal baseline glycemic control compared to those with relatively poor baseline glycemic control.

Effect of mean HbA1c on the association of HbA1c variability and all-cause mortality in patients with type 2 diabetes

AIM

To evaluate the effect of mean HbA1c on the correlation between HbA1c variability and all-cause mortality, and the risks associated with different levels of HbA1c and glycaemic control status in patients with type 2 diabetes.

MATERIALS AND METHODS

Patients with type 2 diabetes and at least three HbA1c measurements within 12-24 months were included. HbA1c variability score, coefficient of variation (CV) and standard deviation (SD) were used to evaluate variability. A variability score of 50 was set as a cutoff to define low and high variability.

RESULTS

A total of 4216 patients were included, of whom 1196 died during the observation period (11.1 ± 3.2 years). All-cause mortality increased with HbA1c variability score and the quartiles of HbA1c CV and SD. The strength of this association was attenuated after adjustment for mean HbA1c, and the risks associated with HbA1c variability and glycaemic control status were similar. The highest associated risk was observed with an HbA1c variability score of >50 and mean HbA1c of ≥7.5%. Mortality risk was significantly higher with a mean HbA1c of ≤6.0% and >8.5% and of ≤6.0% and >8.0% for low and high HbA1c variability, respectively.

CONCLUSIONS

Mean HbA1c contributed to the correlation between HbA1c variability and all-cause mortality. The risks associated with HbA1c variability and glycaemic control status were similar. The relationship between mean HbA1c and mortality presented a J-shaped distribution for both low and high HbA1c variability.

Establishment and Validation of a Risk Prediction Model for Early Diabetic Kidney Disease Based on a Systematic Review and Meta-Analysis of 20 Cohorts

BACKGROUND

Identifying patients at high risk of diabetic kidney disease (DKD) helps improve clinical outcome.

PURPOSE

To establish a model for predicting DKD.

DATA SOURCES

The derivation cohort was from a meta-analysis. The validation cohort was from a Chinese cohort.

STUDY SELECTION

Cohort studies that reported risk factors of DKD with their corresponding risk ratios (RRs) in patients with type 2 diabetes were selected. All patients had estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m² and urinary albumin-to-creatinine ratio (UACR) <30 mg/g at baseline.

DATA EXTRACTION

Risk factors and their corresponding RRs were extracted. Only risk factors with statistical significance were included in our DKD risk prediction model.

DATA SYNTHESIS

Twenty cohorts including 41,271 patients with type 2 diabetes were included in our meta-analysis. Age, BMI, smoking, diabetic retinopathy, hemoglobin A_1c, systolic blood pressure, HDL cholesterol, triglycerides, UACR, and eGFR were statistically significant. All these risk factors were included in the model except eGFR because of the significant heterogeneity among studies. All risk factors were scored according to their weightings, and the highest score was 37.0. The model was validated in an external cohort with a median follow-up of 2.9 years. A cutoff value of 16 was selected with a sensitivity of 0.847 and a specificity of 0.677.

LIMITATIONS

There was huge heterogeneity among studies involving eGFR. More evidence is needed to power it as a risk factor of DKD.

CONCLUSIONS

The DKD risk prediction model consisting of nine risk factors established in this study is a simple tool for detecting patients at high risk of DKD.

HbA1C Variability Is Strongly Associated with Development of Macroalbuminuria in Normal or Microalbuminuria in Patients with Type 2 Diabetes Mellitus: A Six-Year Follow-Up Study

Background

Glycemic variability is associated with higher risk of microvascular complications in patients with type 2 diabetes.

Aim

To test the hypothesis that glycemic variability can contribute to progression to macroalbuminuria in normal or microalbuminuria in patients with type 2 diabetes.

Design

This prospective study enrolled 193 patients with type 2 diabetes at a tertiary medical center.

Methods

For each patient, the intrapersonal glycemic variability (mean, SD, and coefficient of variation of HbA1c) was calculated using all measurements obtained three years before the study. Patients were divided into four groups stratified by both urine albumin/creatinine ratio and HbA1c-SD. The presence of macroalbuminuria was assessed with Kaplan–Meier plots and compared by log-rank test.

Results

Of the 193 patients, 83 patients were in the macroalbuminuria state. Patients in the initial macroalbuminuria group after enrollment had the highest diabetes duration, mean, CV-HbA1c and HbA1c-SD, and uric acid level, and the lowest estimate glomerular filtration rate, followed by subsequent macroalbuminuria and without macroalbuminuria groups. Patients with microalbuminuria and high HbA1c-SD showed the highest progression rate to macroalbuminuria, after a six-year follow-up study by Kaplan–Meier Plots and compared by log-rank test.

Conclusions

Higher HbA1C variability is more likely to progress to macroalbuminuria in those patients who are already in a microalbuminuria state. We recommend that clinicians should aggressively control blood glucose to an acceptable range and avoid blood glucose fluctuations by individualized treatment to prevent renal status progression.

Visit-to-visit variability of glycemia and vascular complications: the Hoorn Diabetes Care System cohort

BACKGROUND

Glycemic variation has been suggested to be a risk factor for diabetes-related complications. Previous studies did not address confounding of diabetes duration, number of visits and length of follow-up. Here, we characterize glycemic variability over time and whether its relation to diabetes-related complications and mortality is independent from diabetes- and follow-up duration.

MATERIALS AND METHODS

Individuals with type 2 diabetes (n = 6770) from the Hoorn Diabetes Care System cohort were included in this study. The coefficient of variation (CV) was calculated over 5-year sliding intervals. People divided in quintiles based on their CV. Cox proportional hazard models were used to investigate the role of glycemic CV as risk factor in diabetes-related complications and mortality.

RESULTS

The coefficient of variation of glucose (FG-CV) increased with time, in contrast to HbA1c (HbA1c-CV). People with a high FG-CV were those with an early age of diabetes onset (Δ_Q5-Q1 = - 2.39 years), a higher BMI (Δ_Q5-Q1 = + 0.92 kg/m²), an unfavorable lipid profile, i.e. lower levels of HDL-C (Δ_Q5-Q1 = - 0.06 mmol/mol) and higher triglycerides (Δ_Q5-Q1 =+ 1.20 mmol/mol). People with the highest FG-CV in the first 5-year interval showed an increased risk of insulin initiation, retinopathy, macrovascular complications and mortality independent of mean glycemia, classical risk factors and medication use. For HbA1c, the associations were weaker and less consistent.

CONCLUSIONS

Individuals with a higher FG-CV have an unfavorable metabolic profile and have an increased risk of developing micro- and macrovascular complications and mortality. The association of HbA1c-CV with metabolic outcomes and complications was less consistent in comparison to FG-CV.

Discordance in risk factors for the progression of diabetic retinopathy and diabetic nephropathy in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

We aimed to investigate whether there are differences in the risk factors or markers for the progression of diabetic retinopathy (DR) and diabetic nephropathy (DN) in type 2 diabetes mellitus.

MATERIALS AND METHODS

We carried out a 3-year retrospective cohort study of 604 patients with type 2 diabetes mellitus. The outcomes were the progression of DR (worsening of the DR stage) and DN (an estimated glomerular filtration rate decline >12%) at the 3-year follow up. The mean hemoglobin A1c (HbA1c) level and HbA1c variability (HbA1c-VAR) were calculated.

RESULTS

The mean HbA1c and HbA1c-VAR levels were higher in the DR progressors (n = 67) than in the DR non-progressors (n = 537). The mean HbA1c was a significant predictor for DR progression independent of the duration of diabetes and HbA1c-VAR levels. The urine albumin-to-creatinine ratio at baseline and HbA1c-VAR levels were higher in the DN progressors (n = 34) than in the DN non-progressors (n = 570). The triglyceride to high-density lipoprotein cholesterol ratio at baseline tended to be higher in the DN progressors than in the DN non-progressors. HbA1c-VAR levels and the triglyceride-to-high-density lipoprotein cholesterol ratio were significant predictors for DN progression independent of estimated glomerular filtration rate and the urine albumin-to-creatinine ratio.

CONCLUSIONS

Average glycemia was significantly associated with progression of DR, whereas glycemic variability and dyslipidemia were significantly associated with progression of DN in type 2 diabetes mellitus.

Asian Americans & chronic kidney disease in a nationally representative cohort

Background

There is a paucity of specific data on early stages of chronic kidney disease (CKD) among Asian Americans (AAs). The objective of this study was to examine the independent association of Asian race/ethnicity and socio-demographic and co-morbidity factors with markers of early kidney damage, ascertained by ACR levels, as well as kidney dysfunction, ascertained by eGFR levels in a large cross-sectional sample of AAs enrolled in the National Health and Nutrition Examination Survey (NHANES).

Methods

Secondary data analyses of the NHANES 2011–2014 data of a nationally representative sample of 5907 participants 18 years and older, US citizens, and of Asian and White race. NHANES data included race (Asian vs. White), as well as other socio-demographic information and comorbidities. Urine albumin-to-creatinine ratio (ACR) categories and estimated glomerular filtration rate (eGFR) were used as indicators for CKD. Descriptive analyses using frequencies, means (standard deviations), and chi-square tests was first conducted, then multivariable logistic regression serial adjustment models were used to examine the associations between race/ethnicity, other socio-demographic factors (age, sex, education), and co-morbidities (obesity, diabetes, hypertension) with elevated ACR levels (A2 & A3 – CKD Stages 3 and 4–5, respectively) as well as reduced eGFR (G3a-G5 and G3b –G5 - CKD Stage 3–5).

Results

AAs were more likely than White participants to have ACR levels > 300 mg/g (A3) (adjusted OR (aOR) (95% CI) 2.77 (1.55, 4.97), p = 0.001). In contrast, adjusted analyses demonstrated that AAs were less likely to have eGFR levels < 60 ml/min/1.73 m2 (G3a-G5) (aOR (95% CI) 0.50 (0.35, 0.72), p < .001).

Conclusions

This is one of the first large U.S. population-based studies of AAs that has shown a comparatively higher risk of elevated ACR > 300 mg/g levels (A3) but lower risk of having eGFR levels < 60 ml/min/1.732 m2 (G3a-G5). The findings support the need to address the gaps in knowledge regarding disparities in risk of early stage CKD among AAs.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1145-5) contains supplementary material, which is available to authorized users.

Association of HbA1C Variability and Renal Progression in Patients with Type 2 Diabetes with Chronic Kidney Disease Stages 3⁻4

Little is known about the predictive value of glycosylated hemoglobin (HbA_1C) variability in patients with advanced chronic kidney disease (CKD). The aim of this study was to investigate whether HbA_1C variability is associated with progression to end-stage renal disease in diabetic patients with stages 3–5 CKD, and whether different stages of CKD affect these associations. Three hundred and eighty-eight patients with diabetes and stages 3–5 CKD were enrolled in this longitudinal study. Intra-individual HbA_1C variability was defined as the standard deviation (SD) of HbA_1C, and the renal endpoint was defined as commencing dialysis. The results indicated that, during a median follow-up period of 3.5 years, 108 patients started dialysis. Adjusted Cox analysis showed an association between the highest tertile of HbA_1C SD (tertile 3 vs. tertile 1) and a lower risk of the renal endpoint (hazard ratio = 0.175; 95% confidence interval = 0.059–0.518; p = 0.002) in the patients with an HbA_1C level ≥ 7% and stages 3–4 CKD, but not in stage 5 CKD. Further subgroup analysis showed that the highest two tertiles of HbA_1C SD were associated with a lower risk of the renal endpoint in the group with a decreasing trend of HbA_1C. Our results demonstrated that greater HbA_1C variability and a decreasing trend of HbA_1C, which may be related to intensive diabetes control, was associated with a lower risk of progression to dialysis in the patients with stages 3–4 CKD and poor glycemic control (HbA1c ≥ 7%).

The association of serum creatinine and estimated glomerular filtration rate variability with diabetic retinopathy in Asians with type 2 diabetes: A nested case-control study

BACKGROUND

Fluctuation of kidney function may signify intra-glomerular microvascular hemodynamic instability. We aim to examine the association of long-term serum creatinine and estimated glomerular filtration rate variability with diabetic retinopathy.

METHODS

We included type 2 diabetes mellitus patients who attended the Diabetes Centre in 2011-2014 and were followed up (median = 3.2 years). Digital colour fundus photographs were assessed for diabetic retinopathy at follow-up. Diabetic retinopathy severity was categorized into non-proliferative diabetic retinopathy and proliferative diabetic retinopathy. We conducted a nested case-control study involving 177 diabetic retinopathy (118 non-proliferative diabetic retinopathy, 50 proliferative diabetic retinopathy) and 327 age- and gender-matched non-diabetic retinopathy. Serum creatinine measured before follow-up visit was obtained (⩾3 readings/patient). Variability was calculated as intra-individual standard deviation/√ n/( n - 1).

RESULTS

Diabetic retinopathy have higher adjusted-serum creatinine-standard deviation than non-diabetic retinopathy [9.1 (4.9-21.6) vs 5.4 (3.4-10.1) µM, p < 0.001]. After multivariable adjustment, adjusted-serum creatinine-standard deviation was associated with diabetic retinopathy [odds ratio = 1.47, 95% confidence interval (1.02-2.10), p = 0.04]. The area under the curve increased significantly after adding adjusted-serum creatinine-standard deviation [0.70 (0.65-0.75) vs 0.72 (0.68-0.77), p < 0.03]. Proliferative diabetic retinopathy have higher adjusted-serum creatinine-standard deviation than non-proliferative diabetic retinopathy [15.5 (6.6-39.7) vs 7.47 (4.52-17.8) µM, p < 0.001]. After adjustment, adjusted-serum creatinine-standard deviation remained associated with non-proliferative diabetic retinopathy [1.48 (1.04-2.12), p = 0.03] and proliferative diabetic retinopathy [2.43 (1.34-4.39), p = 0.003; p-trend = 0.002]. Similar findings were observed for estimated glomerular filtration rate variability.

CONCLUSION

Serum creatinine and estimated glomerular filtration rate variability is associated with the presence and severity of diabetic retinopathy independent of intra-individual means. This may inform novel therapeutic strategies aiming to achieve stable renal function in type 2 diabetes mellitus.

Risk factors for the development of micro-vascular complications of type 2 diabetes in a single-centre cohort of patients

AIMS

In type 2 diabetes, we aimed at clarifying the role of glycated haemoglobin variability and other risk factors in the development of the main micro-vascular complications: peripheral neuropathy, nephropathy and retinopathy.

METHODS

In a single-centre cohort of 900 patients, glycated haemoglobin variability was evaluated as intra-individual standard deviation, adjusted standard deviation and coefficient of variation of serially measured glycated haemoglobin in the 2-year period before a randomly selected index visit. We devised four models considering different aspects of glycated haemoglobin evolution. Multivariate stepwise logistic regression analysis was performed including the following covariates at the index visit: age, disease duration, body mass index, total cholesterol, high-density lipoprotein cholesterol, triglycerides, sex, smoking habit, hypertension, dyslipidemia, treatment with anti-diabetic drugs, occurrence of macro-vascular events and the presence of another micro-vascular complication.

RESULTS

Males with high mean glycated haemoglobin, long duration of diabetes, presence of macro-vascular events and retinopathy emerged at higher risk for peripheral neuropathy. Development of nephropathy was independently associated with higher glycated haemoglobin variability, older age, male sex, current smoking status, presence of retinopathy, of peripheral neuropathy and of hypertension. Higher mean glycated haemoglobin, younger age, longer duration of diabetes, reduced estimated glomerular filtration rate and the presence of peripheral neuropathy were significantly associated with increased incidence of retinopathy.

CONCLUSION

Glycated haemoglobin variability was associated with increased incidence of nephropathy, while mean glycated haemoglobin emerged as independent risk factor for the development of retinopathy and peripheral neuropathy. The presence of macro-vascular events was positively correlated with peripheral neuropathy. Finally, the occurrence of another micro-vascular complication was found to be a stronger risk factor for developing another micro-vascular complication than the mean or variability of glycated haemoglobin.

Haemoglobin A1c variability as an independent correlate of atherosclerosis and cardiovascular disease in Chinese type 2 diabetes

OBJECTIVE

To examine the association between haemoglobin A1c variability and macrovascular complication in type 2 diabetes.

METHODS

We retrospectively enrolled 5278 diabetes patients with no history of cardiovascular disease and atherosclerosis by ultrasound at their first visit to the hospital from 1999 to 2010. Patients had a median of 4 haemoglobin A1c (range = 3-9) measurements during follow-up. Average haemoglobin A1c and haemoglobin A1c variability were calculated as intra-individual mean, standard deviation, coefficient of variation and adjusted standard deviation. Cardiovascular disease events and ultrasound results were re-evaluated from the medical history at the end of the study.

RESULTS

A total of 972 patients had macrovascular complication. Compared to those without atherosclerosis/cardiovascular disease (n = 4306), haemoglobin A1c intra-individual mean and haemoglobin A1c variability levels were significantly higher in patients with macrovascular complication ( p < 0.001). Multivariable logistic regression analysis showed that haemoglobin A1c variability was associated with macrovascular complication. Moreover, 488 patients with only atherosclerosis had significantly higher haemoglobin A1c intra-individual mean and haemoglobin A1c variability values than those without atherosclerosis/cardiovascular disease ( p < 0.001), but in 484 patients with cardiovascular disease incidents, only higher haemoglobin A1c intra-individual mean level was found ( p = 0.004).

CONCLUSIONS

In Chinese type 2 diabetes, haemoglobin A1c variability was associated with macrovascular complication. Long-term stabilization of glucose is important in diabetes management, especially in the early stage of atherosclerosis.

Haemoglobin A1c variability is a strong, independent predictor of all-cause mortality in patients with type 2 diabetes

AIMS

To evaluate various measures of haemoglobin (Hb) A1c variability, compared with average HbA1c, as independent predictors of mortality.

MATERIALS AND METHODS

The Renal Insufficiency And Cardiovascular Events Italian multicentre study enroled 15 733 patients with type 2 diabetes from 19 diabetes clinics during 2006-2008. A total of 3 to 5 HbA1c measures, obtained during the 2-year period before enrolment, were available from 9 centres (8290 patients) and were used to calculate average HbA1c (HbA1c -MEAN) and HbA1c variability, measured as intra-individual standard deviation (HbA1c-SD), SD adjusted for the number of HbA1c assessments (HbA1c-AdjSD) and coefficient of variation (HbA1c-CV), that is, the HbA1c-SD to HbA1c-MEAN ratio. Vital status on October 31, 2015 was retrieved for 8252 patients (99.5%).

RESULTS

The measures of HbA1c variability increased according to quartiles of HbA1c-MEAN and vice versa. HbA1c-MEAN and measures of HbA1c variability were associated with all-cause mortality; however, the strength of association of HbA1c-MEAN was lower than that of HbA1c -SD, HbA1c-CV or HbA1c-AdjSD, and disappeared after adjusting for confounders and any of the measures of HbA1c variability. Mortality increased with quartiles of HbA1c-MEAN, HbA1c -SD, HbA1c-CV and HbA1c-AdjSD, but only the association with HbA1c variability measures remained after adjustment for confounders and/or each other measure. In the fully adjusted model, mortality risk was lower for HbA1c-SD below the median and higher for HbA1c-SD above the median, regardless of whether HbA1c-MEAN was below or above the median. Conclusions HbA1c variability is a strong, independent predictor of all-cause mortality in type 2 diabetes and appears to be even more powerful than average HbA1c in predicting mortality.

Discovery and validation of serum creatinine variability as novel biomarker for predicting onset of albuminuria in Type 2 diabetes mellitus

AIM

We aim to study association serum creatinine(cr) variability and albuminuria progression.

METHODS

We conducted a retrospective cohort study on patients with Type 2 Diabetes Mellitus at a Diabetes Centre in Singapore ("discovery cohort"). Outcome is worsening of urinary albumin-to-creatinine(ACR) across stages. Cr variability was expressed as adjusted cr-intrapersonal standard deviation(SD) and coefficient-of-variation(cr-CV). A separate cohort was used for validating association between cr variability and albuminuria progression ("validation cohort").

RESULTS

Over median follow-up of 4.2 years, 38.4% of 636 patients had albuminuria progression in the discovery cohort. Increasing log-transformed adjusted cr-intrapersonal SD and cr-CV were significantly associated with albuminuria progression: HRs 1.43 (95%CI 1.11-1.85) and 1.44 (1.11-1.87) respectively in the discovery cohort, and HRs 1.94 (1.09-3.45) and 1.91 (1.05-3.45) respectively in the validation cohort. When stratified by baseline urinary ACR, higher cr variability was significantly associated with albuminuria progression in patients with normoalbuminuria but not microalbuminuria.

CONCLUSIONS

Cr variability independently predicts albuminuria onset. This is evident in patients with normoalbuminuria, suggesting that higher cr variability could herald albuminuria onset.

Visit-to-visit HbA1c variability and systolic blood pressure (SBP) variability are significantly and additively associated with mortality in individuals with type 1 diabetes: An observational study

AIM

To investigate the relationship between variability in both visit-to-visit HbA1c and SBP and mortality in individuals with type 1 diabetes.

METHODS

The Scottish Care Information (SCI) Diabetes dataset was used to identify 5952 individuals with type 1 diabetes for inclusion in this observational study. The SCI-Diabetes dataset allowed access to blood pressure values, HbA1c readings, demographic information and mortality rates for all study participants. Participants were dichotomized to above and below median values for both HbA1c coefficient of variation (CV) and SBP CV, thus dividing participants into 4 cohorts for survival analysis. Survival analysis was carried out over 1430 days. A Cox proportional hazard model was used to allow comparison of mortality between the 4 cohorts.

RESULTS

Of the 5952 patients, death occurred in 416. CV for both HbA1c and SBP were significantly associated with mortality. The median values for HbA1c CV and SBP CV were 8.0 and 8.1, respectively. The hazard ratio for high HbA1c CV only (P = .0015) was 1.78 ± 0.36. The hazard ratio for high SBP CV only (P = .0018) was 1.69 ± 0.33. The hazard ratio for both high HbA1c CV and high SBP CV (P < .00001) was 2.37 ± 0.32.

CONCLUSIONS

Our findings demonstrate that variability of both HbA1c and SBP is significantly and additively associated with mortality in individuals with type 1 diabetes. The variability of these parameters might be useful for risk stratification and is a potential target for future interventional studies.

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.

Diabetic Kidney Disease: Is There a Role for Glycemic Variability?

PURPOSE OF REVIEW

Diabetes is the leading cause of kidney disease globally. Diabetic kidney disease (DKD) is a heterogeneous disorder manifested as albuminuria and/or decreasing GFR. Hyperglycemic burden is the major contributor to the development of DKD. In this article, we review the evidence for the contribution of glycemic variability and the pitfalls associated with use of hemoglobin A1c (A1C), the gold standard for assessment of glucose control, in the setting of DKD.

RECENT FINDINGS

Glycemic variability, characterized by swings in blood glucose levels, can result in generation of mitochondrial reactive oxygen species, a putative inciting factor for hyperglycemia-induced alterations in intracellular metabolic pathways. While there is indirect evidence supporting the role of glycemic variability in the pathogenesis of DKD, definitive data are lacking. A1C has many limitations and is a particularly suboptimal measure in patients with kidney disease, because its accuracy is compromised by variables affecting RBC survival and other factors. Continuous glucose monitoring (CGM) technology has the potential to enable us to use glucose as a more important clinical tool, for a more definitive understanding of glucose variability and its role in DKD. Glycemic variability may be a factor in the development of DKD, but definitive evidence is lacking. Currently, all available glycemic biomarkers, including A1C, have limitations and in the setting of DKD and should be used cautiously. Emerging data suggest that personal and professional CGM will play an important role in managing diabetes in patients with DKD, where risk of hypoglycemia is high.

Effect of long-term glycemic variability on estimated glomerular filtration rate decline among patients with type 2 diabetes mellitus: Insights from the Diabetic Nephropathy Cohort in Singapore

BACKGROUND

In the present study, we examined the association between HbA1c variability and renal disease progression based on estimated glomerular filtration rate (eGFR) decline in patients with type 2 diabetes mellitus (T2DM) in Singapore.

METHODS

Glycemic burden and renal function were retrospectively assessed in 1628 patients in 2002-2014. Multivariable logistic regression was used to assess the relationships between HbA1c variability (expressed as HbA1c coefficient of variation [HbA1c-CV] in quartiles), HbA1c intrapersonal mean (HbA1c-IM), and eGFR decline, adjusted for baseline covariates.

RESULTS

Among patients with relatively good glycemic control (i.e. HbA1c-IM below the median cohort value [8.0%]), HbA1c-CV Quartile 4 was associated with eGFR decline (odds ratio [OR] 1.88; 95% confidence interval [CI] 1.10-3.25). The OR for HbA1c-CV Quartile 4 was 2.20 (95% CI 1.24-3.89) after additional adjustment for HbA1c-IM. Where HbA1c-IM was above the median cohort value, HbA1c-CV Quartiles 3 and 4 were associated with eGFR decline, with ORs of 2.60 (95% CI 1.48-4.55) and 3.29 (95% CI 1.89-5.76) respectively. After further adjusting for HbA1c-IM, the ORs for Quartiles 3 and 4 were 2.69 (95% CI 1.53-4.74) and 3.51 (95% CI 1.98-6.21), respectively.

CONCLUSIONS

Variability in HbA1c is strongly and independently associated with eGFR decline in patients with T2DM independent of mean HbA1c. The findings may highlight the importance of sustained stable glycemic control in management of diabetes mellitus.

Visit-to-Visit Variations in Fasting Plasma Glucose and HbA1c Associated With an Increased Risk of Alzheimer Disease: Taiwan Diabetes Study

OBJECTIVE

The relationship between glycemic variability and the incidence of Alzheimer disease (AD) in patients with type 2 diabetes mellitus (T2DM) is unclear. The aim of this study was to examine visit-to-visit variations in fasting plasma glucose (FPG) and glycated hemoglobin (HbA_1c) represented by the coefficient of variation (CV) and to determine whether they were independently associated with AD, irrespective of HbA_1c and other traditional risk factors in such patients.

RESEARCH DESIGN AND METHODS

Patients with T2DM enrolled in the National Diabetes Care Management Program, age ≥60 years, and without diagnosis of AD (n = 16,706) were included in the study. Potential risk factors were analyzed using extended Cox proportional hazards regression models for competing risk of mortality on AD incidence.

RESULTS

During a median follow-up of 8.88 years, 831 incident cases of AD were identified, with a crude incidence rate of 3.5/1,000 person-years. After adjustment for sociodemographic factors, lifestyle behaviors, diabetes-related variables, FPG and HbA_1c, drug-related variables, and comorbidities, both FPG CV and HbA_1c CV were found to be significant predictors of AD, with corresponding hazard ratios of 1.27 (95% CI 1.06-1.52) for the third tertile in FPG CV and 1.32 (95% CI 1.11-1.58) for the third tertile in HbA_1c CV.

CONCLUSIONS

FPG CV and HbA_1c CV are independently associated with AD. The associations between glycemic variability and AD demonstrated in this study suggest a linked pathophysiological mechanism, which is worthy of further investigation. Further research is required to confirm our results and to evaluate whether FPG CV and HbA_1c CV can be valuable therapeutic targets for patients with T2DM at risk.

The relationship between fasting blood glucose variability and coronary artery collateral formation in type 2 diabetes patients with coronary artery disease

BACKGROUND

Coronary collaterals are an alternative source of blood supply to ischemic myocardium. Well-developed coronary collateral arteries in patients with coronary artery disease (CAD) limit the size of acute myocardial infarction and improves survival. The aim of this study was to investigate the relationship between glycemic variability and coronary collateral formation in patients with type 2 diabetes mellitus and CAD.

METHODS

Consecutive patients undergoing percutaneous coronary intervention or coronary artery bypass grafting procedures were studied. Multivariate logistic regression models were used to examine the association between coronary artery collateral formation graded by Rentrope classification and glycemic variability, measured by coefficient variation of fasting blood glucose.

RESULTS

In our study, we retrospectively enrolled 300 patients, of whom 239 were diabetic (age: 70.1±11.9, 56% men) and 61 were nondiabetic (age: 71.5±11.5, 72% men). Diabetic patients were further stratified as follows: those with poor coronary collateral artery development (n=171, age: 69.7±12.4, 55% men) and those with good coronary collateral artery development (n=68, age 71.1±10.8, 59% men) according to the Rentrope classification. Our findings did not show association between glycemic variability and coronary collateral vessels development after controlling for potential confounders (odds ratio: 2.51; 95% confidence interval: 0.57-11.03; P=0.22). The culprit lesion (≥75% stenosis) in the left anterior descending artery and the right coronary artery was more frequent in the good collateral group compared with the poor collateral group (66 vs. 50%, P=0.02; 63 vs. 45%, P=0.01 respectively).

CONCLUSION

Glycemic variability is not associated with coronary collateral artery formation in patients with type 2 diabetes mellitus and CAD.

Greater HbA1c variability is associated with increased cardiovascular events in type 2 diabetes patients with preserved renal function, but not in moderate to advanced chronic kidney disease

Emerging evidence suggests that glycemic variability may be a more reliable measure of glycemic control than mean HbA1c in type 2 diabetes mellitus. This study aimed to determine if HbA1c variability is associated with cardiovascular events in type 2 diabetic patients and if different renal functions affect such association. This longitudinal study enrolled 8259 diabetic patients from the Kaohsiung Medical University Research Database in 2009 and were followed-up until 2015. Intra-individual HbA1C variability was defined as the standard deviation (SD) of HbA1c and cardiovascular events were defined as hospitalization for coronary artery disease, unstable angina, myocardial infarction, stroke, peripheral artery disease, and cardiovascular death. The patients were grouped into two based on their estimated glomerular filtration rate (eGFR) ≥ 60 or < 60 min/ml/1.73m2. In a mean follow-up period of 6.3 years, cardiovascular events were recorded in 8.9% of the patients. In an adjusted Cox model, high HbA1c SD (hazard ratio, 1.290; 95% confidence interval, 1.008-1.650; p = 0.043), but not mean HbA1c, was associated with significantly increased risk of cardiovascular events in patients with eGFR ≥ 60 min/ml/1.73m2. This association was not seen in patients with eGFR < 60 min/ml/1.73m2. In this study, greater HbA1c variability is associated with increased risk of cardiovascular among patients with preserved renal function, but not in those with moderate to advanced chronic kidney disease.

HbA1c variability in type 2 diabetes is associated with the occurrence of new-onset albuminuria within three years

AIMS

To evaluate the association between HbA1c coefficient of variation (HbA1c-CV) and 3-year new-onset albuminuria risk.

METHODS

A retrospective cohort study involving 716 normoalbuminuric type 2 diabetes patients was conducted between 2010 and 2014. HbA1c-CV was used to categorize patients into low, moderate or high variability groups. Multivariate logistic models were constructed and validated. Integrated discrimination (IDI) and net reclassification (NRI) improvement indices were used to quantify the added predictive value of HbA1c-CV.

RESULTS

The mean age of our cohort was 56.1±12.9years with a baseline HbA1c of 8.3±1.3%. Over 3-years of follow-up, 35.2% (n=252) developed albuminuria. An incremental risk of albuminuria was observed with moderate (6.68-13.43%) and high (above 13.44%) HbA1c-CV categories demonstrating adjusted odds ratios of 1.63 (1.12-2.38) and 3.80 (2.10-6.97) for 3-year new-onset albuminuria, respectively. Including HbA1c-CV for 3-year new-onset albuminuria prediction improved model discrimination (IDI: 0.023, NRI: 0.293, p<0.05). The final model had a C-statistic of 0.760±0.018 on validation.

CONCLUSION

HbA1c-CV improves 3-year prediction of new-onset albuminuria. Together with mean HbA1c, baseline urine albumin-to-creatinine ratio and presence of hypertension, accurate 3-year new-onset albuminuria prediction may be possible.

Variability in glycated albumin levels predicts the progression of diabetic nephropathy

AIM

The present study was performed to assess variability in glycated albumin (GA) using a coefficient of variation (CV) to predict the progression of diabetic nephropathy in type 2 diabetic patients, independently of HbA1c and other conventional risk factors.

METHODS

The present study consecutively enrolled 369 patients with type 2 diabetes mellitus from outpatient clinic. During the follow-up period, GA and HbA1c levels were measured repeatedly (≥5 times), and the CV of GA (GA-CV) was calculated for each patient. The patients were divided into two subgroups: Group 1, a MEAN-HbA1c value <7.2% (55mmol/mol); Group 2, a MEAN-HbA1c value ≥7.2% (55mmol/mol). The primary outcome was the renal composite outcome (RCO), which was based on the progression rates of chronic kidney disease and albuminuria and renal death.

RESULTS

The median follow-up period was 33months. The RCO was developed in 109 patients (29.5%). In Group 1, the third highest and highest quartile groups for GA-CV had higher cumulative incidences of the RCO than those of the lowest quartile group (Q4 vs. Q1: HR=5.43, P=0.007, Q3 vs. Q1: HR=5.16, P=0.009). After adjusting for HbA1c levels and other risk factors, the GA-CV remained significantly associated with the development of the RCO. However, Group 2 did not exhibit any significant differences in terms of the cumulative incidence of the RCO among the four GA-CV quartile groups.

CONCLUSIONS

The present findings suggest that variability in GA may be a better predictor of the progression of diabetic nephropathy in type 2 diabetic patients regardless of HbA1c.

HbA1c, systolic blood pressure variability and diabetic retinopathy in Asian type 2 diabetics

BACKGROUND

The aim of the present study was to examine the association between variability in HbA1c or systolic blood pressure (SBP) and diabetes-specific moderate retinopathy in Asians with type 2 diabetes (T2D).

METHODS

A retrospective study was conducted of 172 cases of moderate diabetic retinopathy (DR) cases and 226 controls without DR, matched for age, sex, and ethnicity. Serial HbA1c and SBP (range 3-6 readings) over the 2 years prior to photographic screening of DR were collected. Intrapersonal mean and SD values for HbA1c (iM-HbA1c and iSD-HbA1c) and SBP (iM-SBP and iSD-SBP) were derived. Moderate DR was assessed from digital retinal photographs and defined as levels >43 using the Early Treatment Diabetic Retinopathy Study scale.

RESULTS

Cases of moderate DR had higher iM-HbA1c (8.2 % vs 7.3 %; P = 0.001), iSD-HbA1c (1.22 vs 0.64; P = 0.001), iM-SBP (136.8 vs 129.6 mmHg; P = 0.001) and iSD-SBP (13.3 vs 11.1; P = 0.002) than controls. In the multivariate regression model adjusted for age, gender, ethnicity, duration of diabetes, SBP, and HbA1c, iM-HbA1c and iM-SBP were significantly associated with moderate DR (odds ratio [OR] 1.80, 95 % confidence interval [CI] 1.37-2.36; and OR 1.03, 95 % CI 1.01-1.05, respectively). Neither iSD-HbA1c nor iSD-SBP were associated with moderate DR. When stratified by HbA1c <7 %, only iSD-SBP remained significantly associated with moderate DR (OR 1.11, 95 % CI 1.01-1.21).

CONCLUSION

In a cohort of Asian patients with T2D, both higher mean HbA1c levels and SBP, but not their variability, were associated with moderate DR. Among those with good glycemic control, wider variability of SBP is associated with moderate DR.

Ten-year hemoglobin A1c trajectories and outcomes in type 2 diabetes mellitus: The Diabetes & Aging Study

AIMS

To classify trajectories of long term HbA1c values in patients after diagnosis of type 2 diabetes and examine each trajectory's associations with subsequent microvascular and macrovascular events and mortality.

METHODS

A longitudinal follow-up of 28,016 patients newly diagnosed with type 2 diabetes was conducted. Latent growth mixture modeling was used to identify ten-year HbA1c trajectories. Cox proportional hazards models were used to assess how HbA1c trajectories were associated with events (microvascular and macrovascular) and mortality.

RESULTS

We identified 5 HbA1c trajectories: "low stable" (82.5%), "moderate increasing late" (5.1%), "high decreasing early" (4.9%), "moderate peaking late" (4.1%) and "moderate peaking early" (3.3%). After adjusting for average HbA1c, compared to the low stable trajectory, all non-stable trajectories were associated with higher incidences of microvascular events (hazard ratio (HR) range, 1.28 (95% CI, 1.08-1.53) (high decreasing early) to 1.45 (95% CI, 1.20-1.75) (moderate peaking early)). The high decreasing early trajectory was associated with an increased mortality risk (HR, 1.27 (95% CI, 1.03-1.58)). Trajectories were not associated with macrovascular events.

CONCLUSIONS

Non-stable HbA1c trajectories were associated with greater risk of microvascular events and mortality. These findings suggest a potential benefit of early diabetes detection, prioritizing good glycemic control, and maintaining control over time.

Relationship between daily and day-to-day glycemic variability and increased oxidative stress in type 2 diabetes

AIMS

To determine the association of daily and day-to-day glucose variability with oxidative stress.

METHODS

This was a cross-sectional analysis of 68 patients with type 2 diabetes mellitus (T2DM) over 72h of continuous glucose monitoring. Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) were measured before breakfast on day 1. Glucose variability, mean glucose level (MGL), mean amplitude of glycemic excursions (MAGE), mean of daily differences (MODD) in glucose levels and area under the postprandial plasma glucose curve (AUC_PP) were measured on days 2 and 3. Plasma oxidant capacity against N,N-diethylparaphenylenediamine was measured with the diacron-reactive oxygen metabolites (d-ROMs) test on day 1.

RESULTS

Overall, 66.2% males with the mean age of 63.2±12.6years, diabetes duration of 12.9±10.4years, and HbA1c level of 8.1±1.6% (65±17mmol/mol) were included. MGL (r=0.330), HbA1c (r=0.326), MAGE (r=0.565), MODD (r=0.488), and AUC_PP (r=0.254) exhibited significant correlations with d-ROMs and not FPG; these correlations remained significant after adjustment for clinical factors (sex, age, duration of diabetes, smoking habit, insulin use, statin use, angiotensin II receptor blocker use, BMI, LDL-C, HDL-C, TG, eGFR, and systolic blood pressure) (R²=0.268, R²=0.268, R²=0.417, R²=0.314, and R²=0.347, respectively). MAGE was significantly correlated with MODD (r=0.708) and MAGE and MODD were independently correlated with d-ROMs by multivariate analysis.

CONCLUSIONS

Therefore, oxidative stress is associated with daily and day-to-day glucose variability in patients with T2DM.

Risk Factors for the Development and Progression of Diabetic Kidney Disease in Patients with Type 2 Diabetes Mellitus and Advanced Diabetic Retinopathy

BACKGROUND

Some patients with type 2 diabetes mellitus (T2DM) do not develop diabetic kidney disease (DKD) despite the presence of advanced diabetic retinopathy (DR). We aimed to investigate the presence of DKD and its risk factors in patients with T2DM and advanced DR.

METHODS

We conducted a cross-sectional study in 317 patients with T2DM and advanced DR. The phenotypes of DKD were divided into three groups according to the urine albumin/creatinine ratio (uACR, mg/g) and estimated glomerular filtration rate (eGFR, mL/min/1.73 m²): no DKD (uACR <30 and eGFR ≥60), non-severe DKD (uACR ≥30 or eGFR <60), and severe DKD (uACR ≥30 and eGFR <60). Mean systolic and diastolic blood pressure, mean glycosylated hemoglobin (HbA1c) level, and HbA1c variability (standard deviation [SD] of serial HbA1c values or HbA1c-SD) were calculated for the preceding 2 years.

RESULTS

The prevalence of no DKD, non-severe DKD, and severe DKD was 37.2% (n=118), 37.0% (n=117), and 25.8% (n=82), respectively. HbA1c-SD and the triglyceride/high density lipoprotein cholesterol (TG/HDL-C) ratio correlated positively with uACR and negatively with eGFR. Multiple linear regression analyses showed that the HbA1c-SD and TG/HDL-C ratio were significantly related with eGFR. Multiple logistic regression analyses after adjusting for several risk factors showed that HbA1c-SD and the TG/HDL-C ratio were significant risk factors for severe DKD.

CONCLUSION

The prevalence of DKD was about 60% in patients with T2DM and advanced DR. HbA1c variability and TG/HDL-C ratio may affect the development and progression of DKD in these patients.

The Protective Effect of Antioxidants Consumption on Diabetes and Vascular Complications

Obesity and diabetes is generally accompanied by a chronic state of oxidative stress, disequilibrium in the redox balance, implicated in the development and progression of complications such as micro- and macro-angiopathies. Disorders in the inner layer of blood vessels, the endothelium, play an early and critical role in the development of these complications. Blunted endothelium-dependent relaxation and/or contractions are quietly associated to oxidative stress. Thus, preserving endothelial function and oxidative stress seems to be an optimization strategy in the prevention of vascular complications associated with diabetes. Diet is a major lifestyle factor that can greatly influence the incidence and the progression of type 2 diabetes and cardiovascular complications. The notion that foods not only provide basic nutrition but can also prevent diseases and ensure good health and longevity is now attained greater prominence. Some dietary and lifestyle modifications associated to antioxidative supply could be an effective prophylactic means to fight against oxidative stress in diabesity and complications. A significant benefit of phytochemicals (polyphenols in wine, grape, teas), vitamins (ascorbate, tocopherol), minerals (selenium, magnesium), and fruits and vegetables in foods is thought to be capable of scavenging free radicals, lowering the incidence of chronic diseases. In this review, we discuss the role of oxidative stress in diabetes and complications, highlight the endothelial dysfunction, and examine the impact of antioxidant foods, plants, fruits, and vegetables, currently used medication with antioxidant properties, in relation to the development and progression of diabetes and cardiovascular complications.

Long-term Variability in Glycemic Control Is Associated With White Matter Hyperintensities in APOE4 Genotype Carriers With Type 2 Diabetes

OBJECTIVE

We assessed whether the apolipoprotein ε4 (APOE4) genotype affects the relationship of variability in long-term glycemic control (measured by HbA1c SD of multiple measurements) with white matter hyperintensities (WMHs) in elderly patients with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

WMH volume was generated from structural T1 and fluid-attenuated inversion recovery MRI in each subject. The analysis included 124 subjects; 27 (21.8%) had one or more APOE4 alleles.

RESULTS

HbA1c variability was associated with significantly higher WMH in APOE4 carriers (r = 0.47, P = 0.03), controlling for age, sex, mean HbA1c, number of follow-up years, and a composite of cardiovascular risk factors, but not in noncarriers (r = -0.04, P = 0.71; P for interaction = 0.050).

CONCLUSIONS

The results suggest that the APOE4 genotype affects the relationship of long-term glycemic control with WMH load so that APOE4 carriers may be more vulnerable to the insults of poor control.

Clinical implications of oxidative stress and potential role of natural antioxidants in diabetic vascular complications

AIMS

The possible link between hyperglycaemia-induced oxidative stress (OxS) and diabetic complications is suggested by many in vitro studies. However, not much attention has been paid to the clinical evidence supporting this hypothesis, as well as to their possible therapeutic implications.

DATA SYNTHESIS

Some prospective studies show a direct correlation between an increase in OxS biomarkers and the appearance of diabetes complications. This is consistent with the evidence that any acute increase of glycaemia, particularly post-prandial, and hypoglycaemia causes endothelial dysfunction and inflammation, through the generation of an OxS. However, the detection of free radicals is difficult as they are highly reactive molecules with a short half-life. Instead, the metabolites of OxS are measured. Interventional trials with supplemented antioxidants have failed to show any beneficial effects. Conversely, natural foods show very promising results.

CONCLUSIONS

The "new antioxidant" approach includes the possibility of controlling free radical production and increasing intracellular antioxidant defence, a concept different from the old one, when antioxidant activities implied scavenging the free radicals already produced. A synergistic action in this respect could convincingly be obtained with a balanced 'Mediterranean Diet' (MedD) type. Early intensive glucose control is still the best strategy to avoid OxS and its associated diabetes complications.

Association of the average rate of change in HbA1c with severe adverse events: a longitudinal evaluation of audit data from the Bavarian Disease Management Program for patients with type 2 diabetes mellitus

AIMS/HYPOTHESIS

In patients with type 2 diabetes mellitus, the effects of HbA1c variability on macrovascular events remain uncertain. The present investigation evaluates the association of HbA1c variability with non-fatal cardiovascular events, emergency admissions and episodes of severe hypoglycaemia in a cohort of patients newly started on insulin therapy.

METHODS

HbA1c variability was defined as the rate of change in values between observations. The medical records of 406,356 patients enrolled in a disease management programme for type 2 diabetes mellitus were analysed to identify a cohort of 13,777 patients with observed transition to insulin therapy. The cohort was observed for a period of at least 5 years. Cox regression models were applied to quantify the association of HbA1c variability with the events of interest.

RESULTS

The models reveal a significant non-linear association between HbA1c variability and the risk of experiencing myocardial infarction, stroke and hypoglycaemia. The lowest risk is seen with a variability of approximately 0.5% (5.5 mmol/mol) per quarter. Using Cox models to predict survival curves for the cohort with hypothetical HbA1c variability of 0.5% (5.5 mmol/mol) and 1.5% (16.4 mmol/mol) per quarter, the proportion experiencing myocardial infarction within 2 years increases significantly from 1% to 10%. The proportion experiencing stroke increases from 1% to 29%, hypoglycaemia from 2% to 24% and the risk of emergency admission from 2% to 21%.

CONCLUSIONS/INTERPRETATION

In patients newly started on insulin therapy, rapid and higher HbA1c variability is associated with an increased risk of myocardial infarction, stroke, severe hypoglycaemia and emergency admission.

Specialist-led diabetes registries and predictors of poor glycemic control in type 2 diabetes: Insights into the functionally refractory patient from the LMC Diabetes Registry database

BACKGROUND

The aim of the present study was to explore features associated with glycemic control in type 2 diabetes (T2D) patients undergoing care by specialist clinics.

METHODS

Literature searches identified diabetes registries whose databases recorded outcomes of specialist care. The LMC Diabetes Registry database (n = 58 280; LMC) was queried to identify patients with T2D who had been seen in a defined 14-month period. Logistic regression modeling was used to identify predictors of glycemic control in these patients. Poor glycemic control was defined as HbA1c ≥9.0% (75 mmol/mol) despite specialist care for ≥1 year.

RESULTS

Few published registry-based studies have discussed glycemic control and outcomes of specialist care for T2D. Among 10 590 LMC patients with T2D, mean HbA1c was 7.6% (60 mmol/mol), with 38% of patients meeting the Canadian Diabetes Association target of ≤7.0% (53 mmol/mol). Overall, 15% showed poor glycemic control with persistent HbA1c ≥9.0% (75 mmol/mol); among insulin-treated patients (n = 3856), 28% met this criterion. Patient characteristics independently associated with poor glycemic control included early age of onset, the number of diabetes education program visits, the number of oral therapies, and insulin use.

CONCLUSIONS

Type 2 diabetes patients with poor glycemic control are found disproportionately in referral specialist care clinics. These functionally refractory patients demonstrate features that may assist in predicting their potential outcome, and may represent a group with specific barriers to care. Specialist patient registries, such as the LMC Diabetes Registry, may provide critical information regarding this cohort.

Long-term Glycemic Variability and Risk of Adverse Outcomes: A Systematic Review and Meta-analysis

OBJECTIVE

Glycemic variability is emerging as a measure of glycemic control, which may be a reliable predictor of complications. This systematic review and meta-analysis evaluates the association between HbA1c variability and micro- and macrovascular complications and mortality in type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Medline and Embase were searched (2004-2015) for studies describing associations between HbA1c variability and adverse outcomes in patients with type 1 and type 2 diabetes. Data extraction was performed independently by two reviewers. Random-effects meta-analysis was performed with stratification according to the measure of HbA1c variability, method of analysis, and diabetes type.

RESULTS

Seven studies evaluated HbA1c variability among patients with type 1 diabetes and showed an association of HbA1c variability with renal disease (risk ratio 1.56 [95% CI 1.08-2.25], two studies), cardiovascular events (1.98 [1.39-2.82]), and retinopathy (2.11 [1.54-2.89]). Thirteen studies evaluated HbA1c variability among patients with type 2 diabetes. Higher HbA1c variability was associated with higher risk of renal disease (1.34 [1.15-1.57], two studies), macrovascular events (1.21 [1.06-1.38]), ulceration/gangrene (1.50 [1.06-2.12]), cardiovascular disease (1.27 [1.15-1.40]), and mortality (1.34 [1.18-1.53]). Most studies were retrospective with lack of adjustment for potential confounders, and inconsistency existed in the definition of HbA1c variability.

CONCLUSIONS

HbA1c variability was positively associated with micro- and macrovascular complications and mortality independently of the HbA1c level and might play a future role in clinical risk assessment.

Visit-to-Visit Glucose Variability Predicts the Development of End-Stage Renal Disease in Type 2 Diabetes: 10-Year Follow-Up of Taiwan Diabetes Study

The purpose of this study was to examine the association of glucose variability using coefficient of variation of fasting plasma glucose (FPG-CV) and coefficient of variation of glycated hemoglobin (HbA1c-CV) to end-stage renal disease (ESRD) in 31,841 Chinese patients with type 2 diabetes.Patients with type 2 diabetes enrolled in National Diabetes Care Management Program, aged ≧30 years, and free of ESRD (n = 31,841) in January 1, 2002 to December 31, 2004 were included. Extended Cox proportional hazards regression models with competing risk of all-cause mortality were used to evaluate risk factors on ESRD incidence. Patients were followed till 2012.After a median follow-up period of 8.23 years, 1642 patients developed ESRD, giving a crude incidence rate of 6.27/1000 person-years (6.36 for men, 6.19 for women). After the multivariate adjustment, both FPG-CV and HbA1c-CV were independent predictors of ESRD with corresponding hazard ratios of 1.20 (95% confidence interval [CI] 1.01, 1.41), 1.24 (95% CI 1.05, 1.46) in HbA1c-CV from fourth to fifth quintile and 1.23 (95% CI 1.03, 1.47) in FPG-CV from fifth quintile.One-year visit-to-visit glucose variability expressed by FPG-CV and HbA1c-CV predicted development of ESRD in patients with type 2 diabetes, suggesting therapeutic strategies toward a goal to minimize glucose fluctuation.