Hemoglobin A1c variability as an independent correlate of cardiovascular disease in patients with type 2 diabetes: a cross-sectional analysis of the renal insufficiency and cardiovascular events (RIACE) Italian multicenter study

Glycated Hemoglobin Variability Is Associated With Adverse Outcomes in Patients With Heart Failure Irrespective of Diabetic Status

BACKGROUND

The effect of glycated hemoglobin (HbA1c) variability on adverse outcomes in patients with heart failure (HF) is unclear. We aim to investigate the predictive value of HbA1c variability on the risks of all-cause death and HF rehospitalization in patients with HF irrespective of their diabetic status.

METHODS AND RESULTS

Using a previously validated territory-wide clinical data registry, HbA1c variability was assessed by average successive variability (ASV) or SD of all HbA1c measurements after HF diagnosis. Multivariable Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) and its corresponding 95% CI. A total of 65 950 patients with HF were included in the study. Over a median follow-up of 6.7 (interquartile range, 4.0-10.6) years, 34 508 patients died and 52 446 required HF rehospitalization. Every unit increment of variability in HbA1c was significantly associated with higher HF rehospitalization (HR ASV, 1.20 [95% CI, 1.18-1.23]) and all-cause death (HR ASV, 1.50 [95% CI, 1.47-1.53]). Diabetes significantly modified the association between HbA1c variability and outcomes (Pinteraction<0.001). HbA1c variability in patients with HF without diabetes conferred a higher risk of rehospitalization (HR ASV, 1.92 [95% CI, 1.70-2.17] versus HR ASV, 1.19 [95% CI, 1.17-1.21]), and all-cause death (HR ASV, 3.90 [95% CI, 3.31-4.61] versus HR ASV, 1.47 [95% CI, 1.43-1.50] compared with patients with diabetes).

CONCLUSIONS

HbA1c variability is significantly associated with greater risk of rehospitalization and all-cause death in patients with HF, irrespective of their diabetic status. These observations were more pronounced in patients with HF without diabetes.

Visit to Visit Hemoglobin A1c Variation and Long-term Risk of Major Adverse Limb Events in Patients With Type 2 Diabetes

CONTEXT

Glycemic variation had been demonstrated to be associated with several complications of diabetes.

OBJECTIVE

Investigation of the association between visit to visit hemoglobin A1c (HbA1c) variation and the long-term risk of major adverse limb events (MALEs).

METHODS

Retrospective database study. Average real variability was used to represent glycemic variations with all the HbA1c measurements during the 4 following years after the initial diagnosis of type 2 diabetes. Participants were followed from the beginning of the fifth year until death or the end of the follow-up. The association between HbA1c variations and MALEs was evaluated after adjusting for mean HbA1c and baseline characteristics. Included were 56 872 patients at the referral center with a first diagnosis of type 2 diabetes, no lower extremity arterial disease, and at least 1 HbA1c measurement in each of the 4 following years were identified from a multicenter database. The main outcome measure was incidence of a MALE, which was defined as the composite of revascularization, foot ulcers, and lower limb amputations.

RESULTS

The average number of HbA1c measurements was 12.6. The mean follow-up time was 6.1 years. The cumulative incidence of MALEs was 9.25 per 1000 person-years. Visit to visit HbA1c variations were significantly associated with MALEs and lower limb amputation after multivariate adjustment. People in the highest quartile of variations had increased risks for MALEs (HR 1.25, 95% CI 1.10-1.41) and lower limb amputation (HR 3.05, 95% CI 1.97-4.74).

CONCLUSION

HbA1c variation was independently associated with a long-term risk of MALEs and lower limb amputations in patients with type 2 diabetes.

Intensified glycemic control by HbA1c for patients with coronary heart disease and Type 2 diabetes: a review of findings and conclusions

The occurrence and development of coronary heart disease (CHD) are closely linked to fluctuations in blood glucose levels. While the efficacy of intensified treatment guided by HbA1c levels remains uncertain for individuals with diabetes and CHD, this review summarizes the findings and conclusions regarding HbA1c in the context of CHD. Our review showed a curvilinear correlation between regulated level of HbA1c and therapeutic effectiveness of intensified glycemic control among patients with type 2 diabetes and coronary heart disease. It is necessary to optimize the dynamic monitoring indicators of HbA1c, combine genetic profiles, haptoglobin phenotypes for example and select more suitable hypoglycemic drugs to establish more appropriate glucose-controlling guideline for patients with CHD at different stage of diabetes.

Long-Term Risk of Cardiovascular Disease Among Type 2 Diabetes Patients According to Average and Visit-to-Visit Variations of HbA1c Levels During the First 3 Years of Diabetes Diagnosis

BACKGROUND

It remains unclear whether a combination of glycemic variability and glycated hemoglobin (HbA1c) status leads to a higher incidence of cardiovascular disease (CVD). Therefore, to investigate CVD risk according to the glucose control status during early diabetes, we examined visit-to-visit HbA1c variability among patients with type 2 diabetes (T2DM).

METHODS

In this 9-year retrospective study, we measured HbA1c levels at each visit and tracked the change in HbA1c levels for 3 years after the first presentation (observation window) in newly diagnosed T2DM patients. We later assessed the occurrence of CVD in the last 3 years (target outcome window) of the study period after allowing a 3-year buffering window. The HbA1c variability score (HVS; divided into quartiles, HVS_Q1-4) was used to determine visit-to-visit HbA1c variability.

RESULTS

Among 4,817 enrolled T2DM patients, the mean HbA1c level was < 7% for the first 3 years. The group with the lowest HVS had the lowest rate of CVD (9.4%; 104/1,109 patients). The highest incidence of CVD of 26.7% (8/30 patients) was found in HVS [≥ 9.0%]_Q3, which was significantly higher than that in HVS [6.0-6.9%]_Q1 (P = 0.006), HVS [6.0-6.9%]_Q2 (P = 0.013), HVS [6.0-6.9%]_Q3 (P = 0.018), and HVS [7.0-7.9%]_Q3 (P = 0.040).

CONCLUSION

To our knowledge, this is the first long-term study to analyze the importance of both HbA1c change and visit-to-visit HbA1c variability during outpatient visits within the first 3 years. Lowering glucose levels during early diabetes may be more critical than reducing visit-to-visit HbA1c variability.

Clinical and Pharmacotherapeutic Profile of Patients with Type 2 Diabetes Mellitus Admitted to a Hospital Emergency Department

Type 2 diabetes mellitus (T2DM) is closely associated with other pathologies, which may require complex therapeutic approaches. We aim to characterize the clinical and pharmacological profile of T2DM patients admitted to an emergency department. Patients aged ≥65 years and who were already using at least one antidiabetic drug were included in this analysis. Blood glycemia, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hemoglobin were analyzed for each patient, as well as personal pathological history, diagnosis(s) at admission, and antidiabetic drugs used before. Outcome variables were analyzed using Pearson's Chi-Square, Fisher's exact test, and linear regression test. In total, 420 patients were randomly selected (48.6% male and 51.4% female). Patients with family support showed a lower incidence of high glycemia at admission (p = 0.016). Higher blood creatinine levels were associated with higher blood glycemia (p = 0.005), and hyperuricemia (HU) (p = 0.001), as well as HU, was associated with a higher incidence of acute cardiovascular diseases (ACD) (p = 0.007). Hemoglobin levels are lower with age (p = 0.0001), creatinine (p = 0.009), and female gender (p = 0.03). The lower the AST/ALT ratio, the higher the glycemia at admission (p < 0.0001). Obese patients with (p = 0.021) or without (p = 0.027) concomitant dyslipidemia had a higher incidence of ACD. Insulin (p = 0.003) and glucagon-like peptide-1 agonists (GLP1 RA) (p = 0.023) were associated with a higher incidence of decompensated heart failure, while sulfonylureas (p = 0.009), metformin-associated with dipeptidyl peptidase-4 inhibitors (DPP4i) (p = 0.029) or to a sulfonylurea (p = 0.003) with a lower incidence. Metformin, in monotherapy or associated with DPP4i, was associated with a lower incidence of acute kidney injury (p = 0.017) or acute chronic kidney injury (p = 0.014). SGLT2i monotherapy (p = 0.0003), associated with metformin (p = 0.026) or with DPP4i (p = 0.007), as well as insulin and sulfonylurea association (p = 0.026), were associated with hydroelectrolytic disorders, unlike GLP1 RA (p = 0.017), DPP4i associated with insulin (p = 0.034) or with a GLP1 RA (p = 0.003). Insulin was mainly used by autonomous and institutionalized patients (p = 0.0008), while metformin (p = 0.003) and GLP1 RA (p < 0.0001) were used by autonomous patients. Sulfonylureas were mostly used by male patients (p = 0.027), while SGLT2 (p = 0.0004) and GLP1 RA (p < 0.0001) were mostly used by patients within the age group 65-85 years. Sulfonylureas (p = 0.008), insulin associated with metformin (p = 0.040) or with a sulfonylurea (p = 0.048), as well as DPP4i and sulfonylurea association (p = 0.031), were associated with higher blood glycemia. T2DM patients are characterized by great heterogeneity from a clinical point of view presenting with several associated comorbidities, so the pharmacotherapeutic approach must consider all aspects that may affect disease progression.

Visit-to-visit glycated hemoglobin A1c variability in adults with type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Current practice uses the latest measure of glycated hemoglobin (HbAlc) to facilitate clinical decision-making. Studies have demonstrated that HbAlc variability links the risk of death and complications of diabetes. However, the role of HbAlc variability is unclear in clinical practice. This systematic review summarized the evidence of visit-to-visit HbAlc variability regarding different metrics in micro- and macro-vascular complications and death in people with type 2 diabetes.

METHODS

We searched PubMed, EMBASE (via OVID), and Cochrane Central Register (CENTRAL, via OVID) for studies investigating the association between HbAlc variability and adverse outcomes in patients with type 2 diabetes and performed random-effects meta-analysis stratified by HbAlc variability metrics in terms of standard deviation (SD), coefficient of variation (CV), and HbAlc variability score (HVS).

RESULTS

In people with type 2 diabetes, the highest quantile of all three HbAlc variability metrics (HbAlc-standard deviation [HbAlc-SD], HbAlc-coefficient of variance [HbAlc-CV], and HVS) is associated with increased risks of all-cause mortality, cardiovascular events, progression to chronic kidney disease, amputation, and peripheral neuropathy. For example, the hazard ratio of HbAlc-SD on all-cause mortality was l.89 with 95% confidence interval (95% CI) l.46-2.45 (HbAlc-CV l.47, 95% CI l.26-l.72; HVS l.67, 95% CI l.34-2.09).

CONCLUSIONS

High HbAlc variability leads to micro- and macro-vascular complications of type 2 diabetes and related death. People with type 2 diabetes and high HbAlc variability need additional attention and care for the potential adverse outcomes.

Early and ongoing stable glycaemic control is associated with a reduction in major adverse cardiovascular events in people with type 2 diabetes: A primary care cohort study

AIM

To determine whether achieving early glycaemic control, and any subsequent glycaemic variability, was associated with any change in the risk of major adverse cardiovascular events (MACE).

MATERIALS AND METHODS

A retrospective cohort analysis from the Oxford-Royal College of General Practitioners Research and Surveillance Centre database-a large, English primary care network-was conducted. We followed newly diagnosed patients with type 2 diabetes, on or after 1 January 2005, aged 25 years or older at diagnosis, with HbA1c measurements at both diagnosis and after 1 year, plus five or more measurements of HbA1c thereafter. Three glycaemic bands were created: groups A (HbA1c < 58 mmol/mol [<7.5%]), B (HbA1c ≥ 58 to 75 mmol/mol [7.5%-9.0%]) and C (HbA1c ≥ 75 mmol/mol [≥9.0%]). Movement between bands was determined from diagnosis to 1 year. Additionally, for data after the first 12 months, a glycaemic variability score was calculated from the number of successive HbA1c readings differing by 0.5% or higher (≥5.5 mmol/mol). Risk of MACE from 1 year postdiagnosis was assessed using time-varying Cox proportional hazards models, which included the first-year transition and the glycaemic variability score.

RESULTS

From 26 180 patients, there were 2300 MACE. Compared with group A->A transition over 1 year, those with C->A transition had a reduced risk of MACE (HR 0.75; 95% CI 0.60-0.94; P = .014), whereas group C->C had HR 1.21 (0.81-1.81; P = .34). Compared with the lowest glycaemic variability score, the greatest variability increased the risk of MACE (HR 1.51; 1.11-2.06; P = .0096).

CONCLUSION

Early control of HbA1c improved cardiovascular outcomes in type 2 diabetes, although subsequent glycaemic variability had a negative effect on an individual's risk.

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.

Implications of fasting plasma glucose variability on the risk of incident peripheral artery disease in a population without diabetes: a nationwide population-based cohort study

Background

Diabetes have been known as a traditional risk factor of developing peripheral artery disease (PAD). However, the study evaluating the impact of long-term glycemic variability on the risk of developing PAD is limited, especially in a general population without diabetes.

Methods

We included 152,931 individuals without diabetes from the Korean National Health Insurance Service–Health Screening Cohort. Fasting plasma glucose (FPG) variability was measured using coefficient variance (FPG-CV), standard deviation (FPG-SD), and variability independent of the mean (FPG-VIM).

Results

A total of 16,863 (11.0%) incident cases of PAD were identified during a median follow-up of 8.3 years. Kaplan–Meier curves showed a progressively increasing risk of PAD in the higher quartile group of FPG variability than in the lowest quartile group (log rank P < 0.001). Multivariable Cox proportional hazard analysis showed the hazard ratio for PAD prevalence as 1.11 (95% CI 1.07–1.16, P < 0.001) in the highest FPG-CV quartile than in the lowest FPG-CV quartile after adjusting for confounding variables, including mean FPG. Similar degree of association was shown in the FPG-SD and FPG-VIM. In sensitivity analysis, the association between FPG variability and the risk of developing PAD persisted even after the participants were excluded based on previously diagnosed diseases, including stroke, coronary artery disease, congestive heart failure, chronic kidney disease, or current smokers or drinkers. Subgroup analysis demonstrated that the effects of FPG variability on the risk of PAD were more powerful in subgroups of younger age, regular exercisers, and those with higher income.

Conclusions

Increased long-term glycemic variability may have a significant prognostic effect for incident PAD in individuals without diabetes.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01448-1.

Association Between Long-Term Visit-to-Visit Hemoglobin A1c and Cardiovascular Risk in Type 2 Diabetes: The ACCORD Trial

Background: To explore the association between visit-to-visit variability of glycated hemoglobin (HbA1c) and cardiovascular outcomes in the patients with type 2 diabetes mellitus (T2DM) of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study.

Methods: We conducted a post-hoc analysis on the ACCORD population including 9,544 participants with T2DM. Visit-to-visit variability of HbA1c was defined as the individual SD, coefficient of variation (CV), and variability independent of the mean (VIM) across HbA1c measurements. The clinical measurements included primary outcome [the first occurrence of non-fatal myocardial infarction (MI), non-fatal stroke or cardiovascular death], total mortality, cardiovascular death, non-fatal MI event, non-fatal stroke, total stroke, heart failure, macrovascular events, and major coronary events (CHD).

Results: Over a median follow-up of 4.85 years, 594 and 268 participants experienced all-cause mortality and cardiovascular mortality, respectively. After adjusting for baseline HbA1c levels and confounding factors, the adjusted hazard ratio (HR) comparing patients in the highest vs. the lowest quartile CV of HbA1c variability was 1.61 (95% CI 1.29–2.00) for the primary outcome. Similar trends for secondary outcome were also observed. There was no association between HbA1c fluctuation and non-fatal stroke. Noticeably, there was 66% greater risk for the all-cause mortality among patients in the highest vs. the lowest quartile (HR 1.66, 95% CI 1.27–2.17).

Conclusions: Greater variability of HbA1c is associated with higher risk for cardiovascular complications and all-cause death in T2DM. Our study stresses the significance of well-controlled glycemic levels for improving cardiovascular outcomes. Further randomized clinical trials are required to confirm these findings.

Changes over Time in Hemoglobin A1C (HbA1C) Levels Predict Long-Term Survival Following Acute Myocardial Infarction among Patients with Diabetes Mellitus

Frequent fluctuations of hemoglobin A1c (HbA_1C) values predict patient outcomes. However, data regarding prognoses depending on the long-term changes in HbA_1C among patients after acute myocardial infarction (AMI) are scarce. We evaluated the prognostic significance of HbA_1C levels and changes among diabetic patients (n = 4066) after non-fatal AMI. All the results of HbA_1C tests up to the 10-year follow-up were obtained. The changes (∆) of HbA_1C were calculated in each patient. The time intervals of ∆HbA_1C values were classified as rapid (<one year) and slow (≥one year) changes. The outcome was all-cause mortality. The highest mortality rates of 53.8% and 35.5% were found in the HbA_1C < 5.5–7% and ∆HbA_1C = −2.5–(−2%) categories. A U-shaped association was observed between HbA_1C and mortality: adjOR = 1.887 and adjOR = 1.302 for HbA_1C < 5.5% and ≥8.0%, respectively, as compared with 5.5–6.5% (p < 0.001). Additionally, ∆HbA_1C was associated with the outcome (U-shaped): adjOR = 2.376 and adjOR = 1.340 for the groups of <−2.5% and ≥2.5% ∆HbA_1C, respectively, as compared to minimal ∆HbA_1C (±0.5%) (p < 0.001). A rapid increase in HbA_1C (but not decrease) was associated with a greater risk of mortality. HbA_1C values and their changes are significant prognostic markers for long-term mortality among AMI-DM patients. ∆HbA_1C and its timing, in addition to absolute HbA_1C values, should be monitored.

Association between visit-to-visit HbA1c variability and the risk of cardiovascular disease in patients with type 2 diabetes

AIM

To investigate the association between visit-to-visit HbA1c variability and the risk of cardiovascular disease in patients with type 2 diabetes.

MATERIALS AND METHODS

We performed a retrospective cohort study of 29 260 patients with at least four HbA1c measurements obtained within 2 years of their first diagnosis of type 2 diabetes. Different HbA1c variability markers were calculated, including the standard deviation (SD), coefficient of variation (CV) and adjusted SD. Cox proportional hazards regression models were used to estimate the association of these HbA1c variability markers with incident cardiovascular disease.

RESULTS

During a mean follow-up of 4.18 years, a total of 3746 incident cardiovascular disease cases were diagnosed. Multivariate-adjusted hazard ratios for cardiovascular disease across the first, second, third and fourth quartiles of HbA1c SD values were 1.00, 1.30 (95% confidence interval [CI] 1.18-1.42), 1.40 (95% CI 1.26-1.55) and 1.59 (95% CI 1.41-1.77) (P for trend <.001), respectively. When we utilized HbA1c CV and adjusted HbA1c SD values as exposures, similar positive associations were observed. HbA1c variability was also associated with the risk of first and recurrent severe hypoglycaemic events. A mediating effect of severe hypoglycaemia was observed between HbA1c variability and incident cardiovascular disease.

CONCLUSIONS

Large visit-to-visit HbA1c variability is associated with an increased risk of cardiovascular disease in patients with type 2 diabetes. Severe hypoglycaemia may mediate the association between HbA1c variability and incident cardiovascular disease.

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.

Effect of Flash Glucose Monitoring on Glycemic Control, Hypoglycemia, Diabetes-Related Distress, and Resource Utilization in the Association of British Clinical Diabetologists (ABCD) Nationwide Audit

OBJECTIVE

The FreeStyle Libre (FSL) flash glucose-monitoring device was made available on the U.K. National Health Service (NHS) drug tariff in 2017. This study aims to explore the U.K. real-world experience of FSL and the impact on glycemic control, hypoglycemia, diabetes-related distress, and hospital admissions.

RESEARCH DESIGN AND METHODS

Clinicians from 102 NHS hospitals in the U.K. submitted FSL user data, collected during routine clinical care, to a secure web-based tool held within the NHS N3 network. The t and Mann-Whitney U tests were used to compare the baseline and follow-up HbA_1c and other baseline demographic characteristics. Linear regression analysis was used to identify predictors of change in HbA_1c following the use of FSL. Within-person variations of HbA_1c were calculated using [Formula: see text].

RESULTS

Data were available for 10,370 FSL users (97% with type 1 diabetes), age 38.0 (±18.8) years, 51% female, diabetes duration 16.0 (±49.9) years, and BMI of 25.2 (±16.5) kg/m² (mean [±SD]). FSL users demonstrated a -5.2 mmol/mol change in HbA_1c, reducing from 67.5 (±20.9) mmol/mol (8.3%) at baseline to 62.3 (±18.5) mmol/mol (7.8%) after 7.5 (interquartile range 3.4-7.8) months of follow-up (n = 3,182) (P < 0.0001). HbA_1c reduction was greater in those with initial HbA_1c ≥69.5 mmol/mol (>8.5%), reducing from 85.5 (±16.1) mmol/mol (10%) to 73.1 (±15.8) mmol/mol (8.8%) (P < 0.0001). The baseline Gold score (score for hypoglycemic unawareness) was 2.7 (±1.8) and reduced to 2.4 (±1.7) (P < 0.0001) at follow-up. A total of 53% of those with a Gold score of ≥4 at baseline had a score <4 at follow-up. FSL use was also associated with a reduction in diabetes distress (P < 0.0001). FSL use was associated with a significant reduction in paramedic callouts and hospital admissions due to hypoglycemia and hyperglycemia/diabetic ketoacidosis.

CONCLUSIONS

We show that the use of FSL was associated with significantly improved glycemic control and hypoglycemia awareness and a reduction in hospital admissions.

Age-specific associations of glycated haemoglobin variability with cardiovascular disease and mortality in patients with type 2 diabetes mellitus: A 10- year cohort study

AIMS

To investigate the associations of increased variability in glycated haemoglobin (HbA1c) with cardiovascular disease (CVD) and mortality risk in patients with diabetes.

MATERIALS AND METHODS

This prospective cohort study included 147 811 patients aged 45 to 84 years with type 2 diabetes mellitus, without CVD and with at least three HbA1c values recorded before baseline in the period 2008 to 2010. HbA1c variability was evaluated using a mixed effects model to reduce regression dilution bias. Age-specific associations (45- 54, 55- 64, 65- 74 and 75- 84 years) between HbA1c variability and risk of CVD and mortality were assessed by Cox regression, adjusted for patient characteristics and usual HbA1c.

RESULTS

After a median follow-up of 7.4 years(1.02 million person-years), an overall incidence of 40 785 events including CVD (incidence 27  793) and all-cause mortalities (incidence 23 175) were identified. Positive log-linear associations between HbA1c variability and CVD and mortality were identified in all age groups. The hazard ratios (HRs) for the composite of CVD and all-cause mortality showed that age was inversely associated with HbA1c variability, with a 28% higher risk per 1% increase in HbA1c variability in the age group 45 to 54 years (all composite outcomes: HR 1.28, 95% confidence interval [CI] 1.21, 1.35), whereas only a 14% higher risk in the 75- 84 age group (all composite outcomes: HR 1.14, 95% CI 1.11, 1.17). Subgroup analysis showed the risk in patients with usual HbA1c <53mmol/mol was about eight times higher than in those with usual HbA1c ≥64mmol/mol.

CONCLUSIONS

HbA1c variability was strongly related to CVD and mortality in patients with diabetes across all age groups. Whilst pursuing optimal HbA1c targets, attention should be given to patients with high HbA1c variability, especially younger patients with good HbA1c control.

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.

Mean and variability of annual haemoglobin A1c are associated with high-risk peripheral artery disease

BACKGROUND

Glucose variability is predictive of cardiovascular events and all-cause mortality. However, the association between peripheral artery disease and glucose variability has not been thoroughly investigated. Therefore, the standard deviation of annual haemoglobin A1c was assessed in patients with type 2 diabetes for evaluating the different risks of peripheral artery disease.

METHODS

A total of 4144 patients underwent an evaluation for the ankle-brachial index and the percentage of mean arterial pressure at the ankle. The first haemoglobin A1c record was retrospectively collected from each year until the ankle-brachial index measurement.

RESULTS

The standard deviation of annual haemoglobin A1c was higher in patients with ankle-brachial index ⩽0.90 than in those with ankle-brachial index >0.90 (1.1 ± 0.9% vs 1.0 ± 0.8%, p = 0.009) and was higher in patients with percentage of mean arterial pressure ⩾45% than in those with percentage of mean arterial pressure <45% (1.1 ± 0.8% vs 1.0 ± 0.8%, p = 0.007). A high standard deviation and mean of annual haemoglobin A1c are associated with high-risk peripheral artery disease, which is defined as a combination of ankle-brachial index ⩽0.90, percentage of mean arterial pressure ⩾45% or both (odds ratio = 1.306; 95% confidence interval = 1.057-1.615; p = 0.014).

CONCLUSION

Fluctuation in the haemoglobin A1c value indicates higher risk for peripheral artery disease in patients with type 2 diabetes and poor glucose control.

Association of Longitudinal Values of Glycated Hemoglobin With Cardiovascular Events in Patients With Type 2 Diabetes and Multivessel Coronary Artery Disease

IMPORTANCE

Glycated hemoglobin (HbA1c) values are used to guide glycemic control, but in patients with type 2 diabetes and multivessel coronary artery disease (CAD), the association of the longitudinal values of HbA1c with cardiovascular outcomes is unclear.

OBJECTIVE

To assess whether longitudinal variation of HbA1c is associated with cardiovascular events in long-term follow-up among patients with diabetes and multivessel CAD.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 888 patients with type 2 diabetes and multivessel CAD in the Medicine, Angioplasty, or Surgery Study (MASS) Registry of the Heart Institute of the University of São Paulo from January 2003 to December 2007. Data were analyzed from January 15, 2018, to October 15, 2019.

EXPOSURE

Longitudinal HbA1c values.

MAIN OUTCOMES AND MEASURES

The combined outcome of all-cause mortality, myocardial infarction, and ischemic stroke.

RESULTS

Of 888 patients with type 2 diabetes and multivessel CAD, 725 (81.6%; median [range] age, 62.4 [55.7-68.0] years; 467 [64.4%] men) had complete clinical and HbA1c information during a median (interquartile range) follow-up period of 10.0 (8.0-12.3) years, with a mean (SD) of 9.5 (3.8) HbA1c values for each patient. The composite end point of death, myocardial infarction, or ischemic stroke occurred in 262 patients (36.1%). A 1-point increase in the longitudinal value of HbA1c was significantly associated with a 14% higher risk of the combined end point of all-cause mortality, myocardial infarction, and ischemic stroke (hazard ratio, 1.14; 95% CI, 1.04-1.24; P = .002) in the unadjusted analysis. After adjusting for baseline factors (ie, age, sex, 2-vessel or 3-vessel CAD, initial CAD treatments, ejection fraction, and creatinine and low-density lipoprotein cholesterol levels), a 1-point increase in the longitudinal value of HbA1c was associated with a 22% higher risk of the combined end point (hazard ratio, 1.22; 95% CI, 1.12-1.35; P < .001).

CONCLUSIONS AND RELEVANCE

Longitudinal increase of HbA1c was independently associated with higher rates of cardiovascular events in patients with type 2 diabetes and multivessel CAD.

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.

Prognostic impact of visit-to-visit glycemic variability on the risks of major adverse cardiovascular outcomes and hypoglycemia in patients with different glycemic control and type 2 diabetes

PURPOSE

The prognostic impact of visit-to-visit glycemic variability on clinical outcomes in patients with different glycemic control and type 2 diabetes remains obscure. We investigated glucose variability and clinical outcomes for patients in the groups of Good glycemic control (GC), Insufficient glycemic control (IC), and Poor glycemic control (PC) in a prospective cohort study.

METHODS

By using data from Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation (ADVANCE), 930 patients were enrolled from 61 centers in China and grouped into GC, IC, and PC according to their glycated hemoglobin A1_c (HbA1_c) and fasting plasma glucose (FPG). Visit-to-visit glycemic variability was defined using the coefficient of variation (CV) of five measurements of HbA1_c and FPG taken 3-24 months after treatment. Multivariable Cox proportional hazards models were employed to estimate adjusted hazard ratio (aHR).

RESULTS

Among 930 patients in the intensive glucose control, 82, 538, and 310 patients were assigned to GC, IC, and PC, respectively. During the median of 4.8 years of follow-up, 322 patients were observed hypoglycemia and 244 patients experienced major adverse cardiovascular events (MACE). The CV of HbA1_c and FPG was significantly lower for GC (6.0 ± 3.8, 11.2 ± 6.2) than IC (8.3 ± 5.6, 17.9 ± 10.6) and PC (9.5 ± 6.3, 19.3 ± 10.8). High glycemic variability was associated with a greater risk of MACE (aHR: 2.21; 95% confidence interval (CI): 1.61-3.03; p < 0.001) and hypoglycemia (aHR: 1.36; 95% CI: 1.04-1.79; p = 0.025) than low glycemic variability in total patients. The consistent trend was also found in subgroups of GC, IC, and PC.

CONCLUSIONS

This prospective cohort study showed that glycemic variability was significantly lower for GC than IC and PC. Furthermore, glycemic variability was associated with the risk of MACE and hypoglycemia in total patients and subgroups of different glycemic control.

What to do with diabetes therapies when HbA1c lowering is inadequate: add, switch, or continue? A MASTERMIND study

BACKGROUND

It is unclear what to do when people with type 2 diabetes have had no or a limited glycemic response to a recently introduced medication. Intra-individual HbA1c variability can obscure true response. Some guidelines suggest stopping apparently ineffective therapy, but no studies have addressed this issue.

METHODS

In a retrospective cohort analysis using the UK Clinical Practice Research Datalink (CPRD), we assessed the outcome of 55,530 patients with type 2 diabetes starting their second or third non-insulin glucose-lowering medication, with a baseline HbA1c > 58 mmol/mol (7.5%). For those with no HbA1c improvement or a limited response at 6 months (HbA1c fall < 5.5 mmol/mol [0.5%]), we compared HbA1c 12 months later in those who continued their treatment unchanged, switched to new treatment, or added new treatment.

RESULTS

An increase or a limited reduction in HbA1c was common, occurring in 21.9% (12,168/55,230), who had a mean HbA1c increase of 2.5 mmol/mol (0.2%). After this limited response, continuing therapy was more frequent (n = 9308; 74%) than switching (n = 1177; 9%) or adding (n = 2163; 17%). Twelve months later, in those who switched medication, HbA1c fell (- 6.8 mmol/mol [- 0.6%], 95%CI - 7.7, - 6.0) only slightly more than those who continued unchanged (- 5.1 mmol/mol [- 0.5%], 95%CI - 5.5, - 4.8). Adding another new therapy was associated with a substantially better reduction (- 12.4 mmol/mol [- 1.1%], 95%CI - 13.1, - 11.7). Propensity score-matched subgroups demonstrated similar results.

CONCLUSIONS

Where glucose-lowering therapy does not appear effective on initial HbA1c testing, changing agents does not improve glycemic control. The initial agent should be continued with another therapy added.

Cardiovascular Autonomic Neuropathy Predicts Higher HbA1c Variability in Subjects with Type 2 Diabetes Mellitus

BACKGROUND

This study aimed to investigate the association between the presence and severity of cardiovascular autonomic neuropathy (CAN) and development of long-term glucose fluctuation in subjects with type 2 diabetes mellitus.

METHODS

In this retrospective cohort study, subjects with type 2 diabetes mellitus who received cardiovascular autonomic reflex tests (CARTs) at baseline and at least 4-year of follow-up with ≥6 measures of glycosylated hemoglobin (HbA1c) were included. The severity of CAN was categorized as normal, early, or severe CAN according to the CARTs score. HbA1c variability was measured as the standard deviation (SD), coefficient of variation, and adjusted SD of serial HbA1c measurements.

RESULTS

A total of 681 subjects were analyzed (294 normal, 318 early, and 69 severe CAN). The HbA1c variability index values showed a positive relationship with the severity of CAN. Multivariable logistic regression analysis showed that CAN was significantly associated with the risk of developing higher HbA1c variability (SD) after adjusting for age, sex, body mass index, diabetes duration, mean HbA1c, heart rate, glomerular filtration rate, diabetic retinopathy, coronary artery disease, insulin use, and anti-hypertensive medication (early CAN: odds ratio [OR], 1.65; 95% confidence interval [CI], 1.12 to 2.43) (severe CAN: OR, 2.86; 95% CI, 1.47 to 5.56). This association was more prominent in subjects who had a longer duration of diabetes (>10 years) and lower mean HbA1c (<7%).

CONCLUSION

CAN is an independent risk factor for future higher HbA1c variability in subjects with type 2 diabetes mellitus. Tailored therapy for stabilizing glucose fluctuation should be emphasized in subjects with CAN.

Glycemic Variation and Cardiovascular Risk in the Veterans Affairs Diabetes Trial

OBJECTIVE

There is uncertainty about the importance of glycemic variability in cardiovascular complications in patients with type 2 diabetes. Using the Veterans Affairs Diabetes Trial (VADT), we investigated the association between variation in fasting glucose and glycated hemoglobin (HbA_1c) over time and the incidence of cardiovascular disease (CVD) and assessed whether this is influenced by intensive or standard glycemic control.

RESEARCH DESIGN AND METHODS

During the VADT, fasting glucose and HbA_1c were measured every 3 months for up to 84 months in 1,791 individuals. Variability measures included coefficient of variation (CV) and average real variability (ARV) for fasting glucose and HbA_1c. Overall mean glucose and HbA_1c measures as well as their maximum and the most recent measurement were also examined.

RESULTS

Variability measures (CV and ARV) of fasting glucose were significantly associated with CVD even after adjusting for other risk factors, including mean fasting glucose. When considering separately groups receiving intensive and standard glycemic control, this relationship was evident in the intensive treatment group but not in the standard group. Additional adjustment for severe hypoglycemic episodes did not alter the relationship between fasting glucose variability and CVD. Interestingly, no HbA_1c measures were associated with CVD after adjusting for multiple baseline risk factors.

CONCLUSIONS

Our analysis indicates that in the VADT, variability of fasting glucose plays a role in the development of CVD complications beyond the influence of standard fasting glucose measures. The adverse consequences of fasting glucose variability on CVD appear greatest in those receiving intensive glucose control.

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.

Prognostic impact of HbA1c variability on long-term outcomes in patients with heart failure and type 2 diabetes mellitus

Background

The prognostic impact of long-term glycemic variability on clinical outcomes in patients with heart failure (HF) and type 2 diabetes mellitus (T2DM) remains unclear. We determined and compared hemoglobin A1c (HbA1c) variability and clinical outcomes for patients with HF with preserved ejection fraction (HFpEF), HF with mid-range ejection fraction (HFmrEF) and HF with reduced ejection fraction (HFrEF) in a prospective longitudinal study.

Methods

Patients with HF and T2DM, undergone 3 or more HbA1c determinations during the first 18 months, were then followed for 42 months. The primary outcome was death from any cause. Secondary outcome was composite endpoints with death and HF hospitalization. Cox proportional hazards models were used to compare outcomes for patients with HFpEF, HFmrEF and HFrEF.

Results

Of 902 patients enrolled, 32.2% had HFpEF, 14.5% HFmrEF, and 53.3% HFrEF. During 42 months of follow-up, 270 (29.9%) patients died and 545 (60.4%) patients experienced composite endpoints of death and HF readmission. The risk of all-cause death or composite endpoints was lower for HFpEF than HFrEF. Moreover, higher HbA1c variability was associated with higher all-cause mortality or composite endpoints and HbA1c variability was an independent predictor of all-cause mortality or composite endpoints, regardless of EF.

Conclusions

This prospective longitudinal study showed that the all-cause death and composite events was lower for HFpEF than HFrEF. HbA1c variability was independently and similarly predictive of death or combined endpoints in the three HF phenotypes.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0739-3) contains supplementary material, which is available to authorized users.

Hemoglobin A1c Variability Predicts Symptoms of Depression in Elderly Individuals With Type 2 Diabetes

OBJECTIVE

This study aimed to analyze the relationship of variability in hemoglobin A_1c (HbA_1c) over years with subsequent depressive symptoms.

RESEARCH DESIGN AND METHODS

Subjects (n = 837) were participants of the Israel Diabetes and Cognitive Decline (IDCD) study, which aimed to examine the relationship of characteristics of long-term type 2 diabetes with cognitive decline. All pertain to a diabetes registry established in 1998, which contains an average of 18 HbA_1c measurements per subject. The results presented here are based on the IDCD baseline examination. Symptoms of depression were assessed using the 15-item version of the Geriatric Depression Scale (GDS). To quantify the association between variability in glycemic control (measured as the SD of HbA_1c measurements [HbA_1c-SD]) since 1998 with the number of depression symptoms at IDCD baseline, incidence rate ratios (IRRs) and corresponding 95% CIs were estimated via negative binomial regression modeling and used to account for the overdispersion in GDS scores.

RESULTS

Subjects' ages averaged 72.74 years (SD 4.63 years), and the mean number of years in the diabetes registry was 8.7 (SD 2.64 years). The mean GDS score was 2.16 (SD 2.26); 10% of subjects had a GDS score ≥6, the cutoff for clinically significant depression. Mean HbA_1c significantly correlated with HbA_1c-SD (r = 0.6625; P < 0.0001). The SD, but not the mean, of HbA_1c measurements was significantly associated with the number of subsequent depressive symptoms. For each additional 1% increase in HbA_1c-SD, the number of depressive symptoms increased by a factor of 1.31 (IRR = 1.31 [95% CI 1.03-1.67]; P = 0.03).

CONCLUSIONS

Variability in glycemic control is associated with more depressive symptoms.

Association of hemoglobin A1c variability and the incidence of heart failure with preserved ejection fraction in patients with type 2 diabetes mellitus and arterial hypertension

BACKGROUND

This study aimed to investigate the association between variability in hemoglobin A1c (HbA1c) and left ventricular (LV) diastolic function and incidence of symptomatic heart failure with preserved ejection fraction (HFpEF) in patients with type 2 diabetes mellitus (T2DM) and arterial hypertension.

METHODS

A retrospective cohort study was conducted on eligible patients with T2DM and hypertension and without clinical signs or symptoms of heart failure in our hospital medical record database. Variability in HbA1c was measured by standard deviation (SD) and coefficient of variation (CV). Risk of new onset of symptomatic HFpEF was evaluated by multivariable cox regression analysis.

RESULTS

A total of 201 subjects were categorized according to the median value of HbA1c variability indicators. Over a median follow-up of 7.3 years, the percentage of subjects who had new incidence of symptomatic HFpEF was higher in those with higher HbA1c-SD level (5/105 vs. 13/96, P=0.029) and higher HbA1c-CV level (5/101 vs. 13/100, P=0.046). Multivariable cox regression analysis also showed that higher HbA1c variability [HbA1c-SD (HR 1.754, 95% CI: 1.003-3.104, P=0.049) or HbA1c-CV (HR 1.604 95% CI: 1.064-2.419, P=0.024)] was associated with the presence of new-onset symptomatic HFpEF, independent of HbA1c-mean level, in T2DM and hypertensive patients. Moreover, lower HbA1c variability generated more prominent improvement in LV diastolic function (E/E') during the follow-up.

CONCLUSIONS

HbA1c variability may provide additional valuable information as a potential predictor of the progression of HFpEF in T2DM and hypertensive patients.

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.

Diabetes Camp as Continuing Education for Diabetes Self-Management in Middle-Aged and Elderly People with Type 2 Diabetes Mellitus

BACKGROUND

Despite the established benefits of diabetes camps for the continuing education of children with type 1 diabetes mellitus, little is known about the long-term metabolic benefits of diabetes camps for middle-aged and elderly people with type 2 diabetes mellitus (T2DM), especially in terms of glycosylated hemoglobin (HbA1c) variability.

METHODS

The 1-year mean and variability of HbA1c before and after the diabetes camp was compared between the participants of the diabetes camp (n=57; median age 65 years [range, 50 to 86 years]; median diabetes duration 14 years [range, 1 to 48 years]). Additional case-control analysis compared the metabolic outcomes of the participants of the diabetes camp and their propensity score-matched controls who underwent conventional diabetes education (n=93).

RESULTS

The levels of HbA1c during the first year after the diabetes camp were comparable to those of the matched controls (P=0.341). In an analysis of all participants of the diabetes camp, the 1-year mean±standard deviation (SD) of HbA1c decreased (P=0.010 and P=0.041) after the diabetes camp, whereas the adjusted SD and coefficient of variance (CV) of HbA1c did not decrease. The adjusted SD and CV significantly decreased after the diabetes camp in participants whose 1-year mean HbA1c was ≥6.5% before the diabetes camp (n=40) and those with a duration of diabetes less than 15 years (n=32).

CONCLUSION

The 1-year mean and SD of HbA1c decreased after the diabetes camp, with significant reduction in the adjusted SD and CV in those with higher baseline HbA1c and a shorter duration of diabetes.

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.

Identifying the independent effect of HbA1c variability on adverse health outcomes in patients with Type 2 diabetes

AIMS

To characterize the relationship between HbA1c variability and adverse health outcomes among US military veterans with Type 2 diabetes.

METHODS

This retrospective cohort study used Veterans Affairs and Medicare claims for veterans with Type 2 diabetes taking metformin who initiated a second diabetes medication (n = 50 861). The main exposure of interest was HbA1c variability during a 3-year baseline period. HbA1c variability, categorized into quartiles, was defined as standard deviation, coefficient of variation and adjusted standard deviation, which accounted for the number and mean number of days between HbA1c tests. Cox proportional hazard models predicted mortality, hospitalization for ambulatory care-sensitive conditions, and myocardial infarction or stroke and were controlled for mean HbA1c levels and the direction of change in HbA1c levels during the baseline period.

RESULTS

Over a mean 3.3 years of follow-up, all HbA1c variability measures significantly predicted each outcome. Using the adjusted standard deviation measure for HbA1c variability, the hazard ratios for the third and fourth quartile predicting mortality were 1.14 (95% CI 1.04, 1.25) and 1.42 (95% CI 1.28, 1.58), for myocardial infarction and stroke they were 1.25 (95% CI 1.10, 1.41) and 1.23 (95% CI 1.07, 1.42) and for ambulatory-care sensitive condition hospitalization they were 1.10 (95% CI 1.03, 1.18) and 1.11 (95% CI 1.03, 1.20). Higher baseline HbA1c levels independently predicted the likelihood of each outcome.

CONCLUSIONS

In veterans with Type 2 diabetes, greater HbA1c variability was associated with an increased risk of adverse long-term outcomes, independently of HbA1c levels and direction of change. Limiting HbA1c fluctuations over time may reduce 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.

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.

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.

Liraglutide Improves Glycemic and Blood Pressure Control and Ameliorates Progression of Left Ventricular Hypertrophy in Patients with Type 2 Diabetes Mellitus on Peritoneal Dialysis

Diabetes mellitus (DM) is a multifactorial disease associated with cardiovascular complications. Patients undergoing peritoneal dialysis also experience an increased incidence of cardiovascular disease. To prevent progression of cardiovascular complications in DM patients, glycemic control is important. In this study, we examined the efficacy and safety of the glucagon-like peptide analog liraglutide for treating type 2 diabetes patients undergoing peritoneal dialysis. Sixteen type 2 diabetes patients on peritoneal dialysis were enrolled. Before liraglutide initiation, 11 patients were on insulin therapy, three were on oral antidiabetic agents, and two were on diet therapy. Of the 16 patients, 12 had switched to liraglutide because of severe hypoglycemia and four because of hyperglycemia. Echocardiography was performed at baseline and 12 months after liraglutide initiation. Hemoglobin A1c, glycosylated albumin, and fasting/postprandial glucose levels gradually decreased after liraglutide initiation. After 6 and 12 months of treatment, postprandial glucose levels showed a significant difference from baseline. Moreover, the mean daily glucose level and glycemic fluctuations decreased. Systolic blood pressure upon waking also decreased. In addition, after 12 months, left ventricular mass index (LVMI) decreased and left ventricular ejection fraction increased. Changes in LVMI positively correlated with morning systolic blood pressure and fasting glucose levels. One patient restarted insulin because of anorexia but severe hypoglycemia was not observed. These findings suggest that liraglutide therapy in type 2 diabetes patients undergoing peritoneal dialysis is safe and effective for decreasing glucose levels, glycemic fluctuations, and blood pressure, apart from improving left ventricular function.

HbA1c below 7% as the goal of glucose control fails to maximize the cardiovascular benefits: a meta-analysis

Objective

Whether lowering glycosylated haemoglobin (HbA1c) level below 7.0 % improves macro-vascular outcomes in diabetes remains unclear. Here, we aimed to assess the effect of relatively tight glucose control resulting in a follow-up HbA1c level of less or more than 7.0 % on cardiovascular outcomes in diabetic patients.

Research design and methods

We systematically searched Medline, Web of science and Cochrane Library for prospective randomized controlled trials published between Jan 1, 1996 and July 1, 2015 that recorded cardiovascular outcome trials of glucose-lowering drugs or strategies in patients with type 2 diabetes mellitus.

Results

Data from 15 studies involving 88,266 diabetic patients with 4142 events of non-fatal myocardial infarction, 6997 of major cardiovascular events, 3517 of heart failure, 6849 of all-cause mortality, 2084 of non-fatal stroke, 3816 of cardiovascular death were included. A 7 % reduction of major cardiovascular events was observed only when relatively tight glucose control resulted in a follow-up HbA1c level above 7.0 % (OR 0.93, 95 % CI 0.88–0.98; I² = 33 %), however, the patients can benefit from reduction incidence of non-fatal myocardial infarction only when the follow-up HbA1c value below 7.0 % (OR 0.85, 95 % CI 0.74–0.96). Apart from the HbA1c value above 7.0 % (OR 1.22, 95 % CI 1.06–1.40), the application of thiazolidinediones (OR 1.39, 95 % CI 1.14–1.69) also increased the risk of heart failure, while the gliptins shows neutral effects to heart failure (OR 1.14, 95 % CI 0.97–1.34).

Conclusions

Relatively tight glucose control has some cardiovascular benefits. HbA1c below 7.0 % as the goal to maximize the cardiovascular benefits remains suspended.

Adjustment of the GRACE score by HemoglobinA1c enables a more accurate prediction of long-term major adverse cardiac events in acute coronary syndrome without diabetes undergoing percutaneous coronary intervention

Background

The Global Registry of Acute Coronary Events (GRACE) risk score is widely recommended for risk assessment in patients with acute coronary syndrome (ACS). Chronic hyperglycemia [hemoglobinA1c (HbA1c)] can independently predict major adverse cardiac events (MACEs) in patients with ACS. We investigated whether the prediction of MACEs with the GRACE score could be improved with the addition of HbA1c content in ACS patients without diabetes mellitus (DM) undergoing percutaneous coronary intervention (PCI).

Methods

We enrolled 549 ACS patients without DM who underwent PCI. The GRACE score and HbA1c content were determined on admission. Correlation was analyzed by Spearman’s rank correlation. Cumulative MACE curve was calculated using the Kaplan–Meier method. Multivariate Cox regression was used to identify predictors of MACEs. Additionally, the predictive value of HbA1c content alone and combined with GRACE score was estimated by the area under the receiver-operating characteristic curve (AUC), continuous net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

Results

During a median of 42.3 months (interquartile range 39.3–44.2 months), 16 (2.9 %) were lost to follow-up, and patients experienced 69 (12.9 %) MACEs: 51 (9.6 %) all-cause deaths and 18 (3.4 %) nonfatal myocardial infarction cases. The GRACE score was positively associated with HbA1c content. Multivariate Cox analysis showed that both GRACE score and HbA1c content were independent predictors of MACEs (hazard ratio 1.030; 95 % CI 1.020–1.040; p < 0.001; 3.530; 95 % CI 1.927–6.466; p < 0.001, respectively). Furthermore, Kaplan–Meier analysis demonstrated increased risk of MACEs with increasing HbA1c content (log-rank 33.906, p < 0.001). Adjustment of the GRACE risk estimate by HbA1c improved the predictive value of the GRACE score [increase in AUC from 0.75 for the GRACE score to 0.80 for the GRACE score plus HbA1c, p = 0.012; IDI = 0.055, p < 0.001; NRI (>0) = 0.70, p < 0.001].

Conclusions

HbA1c content is positively associated with GRACE risk score and their combination further improved the risk stratification for ACS patients without DM undergoing PCI.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0274-4) contains supplementary material, which is available to authorized users.

Association between glycemic control and antidiabetic drugs in type 2 diabetes mellitus patients with cardiovascular complications

PURPOSE

Cardiovascular disease (CVD) is a macrovascular complication in patients with type 2 diabetes mellitus (T2DM). To date, glycemic control profiles of antidiabetic drugs in cardiovascular (CV) complications have not been clearly elucidated. Therefore, this study was conducted retrospectively to assess the association of antidiabetic drugs and glycemic control with CV profiles in T2DM patients. The association of concurrent medications and comorbidities with glycemic control was also investigated.

METHODS

A total of 220 T2DM patients from the University of Malaya Medical Centre, Malaysia, who had at least one CV complication and who had been taking at least one antidiabetic drug for at least 3 months, were included. The associations of antidiabetics, cardiovascular diseases, laboratory parameters, concurrent medications, comorbidities, demographics, and clinical characteristics with glycemic control were investigated.

RESULTS

Sulfonylureas in combination (P=0.002) and sulfonylurea monotherapy (P<0.001) were found to be associated with good glycemic control, whereas insulin in combination (P=0.051), and combination biguanides and insulin therapy (P=0.012) were found to be associated with poor glycemic control. Stroke (P=0.044) was the only type of CVD that seemed to be significantly associated with good glycemic control. Other factors such as benign prostatic hyperplasia (P=0.026), elderly patients (P=0.018), low-density lipoprotein cholesterol levels (P=0.021), and fasting plasma glucose (P<0.001) were found to be significantly correlated with good glycemic control.

CONCLUSION

Individualized treatment in T2DM patients with CVDs can be supported through a better understanding of the association between glycemic control and CV profiles in T2DM patients.

Lack of correlation between the optimal glycaemic control and coronary micro vascular dysfunction in patients with diabetes mellitus: a cross sectional study

Background

Coronary microvascular dysfunction (CMD) is associated with cardiovascular events in type 2 diabetes mellitus (T2DM). Optimal glycaemic control does not always preclude future events. We sought to assess the effect of the current target of HBA1c level on the coronary microcirculatory function and identify predictive factors for CMD in T2DM patients.

Methods

We studied 100 patients with T2DM and 214 patients without T2DM. All of them with a history of chest pain, non-obstructive angiograms and a direct assessment of coronary blood flow increase in response to adenosine and acetylcholine coronary infusion, for evaluation of endothelial independent and dependent CMD. Patients with T2DM were categorized as having optimal (HbA1c < 7 %) vs. suboptimal (HbA1c ≥ 7 %) glycaemic control at the time of catheterization.

Results

Baseline characteristics and coronary endothelial function parameters differed significantly between T2DM patients and control group. The prevalence of endothelial independent CMD (29.8 vs. 39.6 %, p = 0.40) and dependent CMD (61.7 vs. 62.2 %, p = 1.00) were similar in patients with optimal vs. suboptimal glycaemic control. Age (OR 1.10; CI 95 % 1.04–1.18; p < 0.001) and female gender (OR 3.87; CI 95 % 1.45–11.4; p < 0.01) were significantly associated with endothelial independent CMD whereas glomerular filtrate (OR 0.97; CI 95 % 0.95–0.99; p < 0.05) was significantly associated with endothelial dependent CMD. The optimal glycaemic control was not associated with endothelial independent (OR 0.60, CI 95 % 0.23–1.46; p 0.26) or dependent CMD (OR 0.99, CI 95 % 0.43–2.24; p = 0.98).

Conclusions

The current target of HBA1c level does not predict a better coronary microcirculatory function in T2DM patients. The appropriate strategy for prevention of CMD in T2DM patients remains to be addressed.

Delay in treatment intensification increases the risks of cardiovascular events in patients with type 2 diabetes

BACKGROUND

The aim of the study was to evaluate the effect of delay in treatment intensification (IT; clinical inertia) in conjunction with glycaemic burden on the risk of macrovascular events (CVE) in type 2 diabetes (T2DM) patients.

METHODS

A retrospective cohort study was carried out using United Kingdom Clinical Practice Research Datalink, including T2DM patients diagnosed from 1990 with follow-up data available until 2012.

RESULTS

In the cohort of 105,477 patients mean HbA1c was 8.1% (65 mmol/mol) at diagnosis, 11% had a history of cardiovascular disease, and 7.1% experienced at least one CVE during 5.3 years of median follow-up. In patients with HbA1c consistently above 7/7.5% (53/58 mmol/mol, n = 23,101/11,281) during 2 years post diagnosis, 26/22% never received any IT. Compared to patients with HbA1c <7% (<53 mmol/mol), in patients with HbA1c ≥7% (≥53 mmol/mol), a 1 year delay in receiving IT was associated with significantly increased risk of MI, stroke, HF and composite CVE by 67% (HR CI: 1.39, 2.01), 51% (HR CI: 1.25, 1.83), 64% (HR CI: 1.40, 1.91) and 62% (HR CI: 1.46, 1.80) respectively. One year delay in IT in interaction with HbA1c above 7.5% (58 mmol/mol) was also associated with similar increased risk of CVE.

CONCLUSIONS

Among patients with newly diagnosed T2DM, 22% remained under poor glycaemic control over 2 years, and 26% never received IT. Delay in IT by 1 year in conjunction with poor glycaemic control significantly increased the risk of MI, HF, stroke and composite CVE.

Association between hemoglobin A1c variability and subclinical coronary atherosclerosis in subjects with type 2 diabetes

AIMS

We examined the association between hemoglobin A1c (HbA1c) variability and subclinical coronary atherosclerosis in subjects with type 2 diabetes.

METHODS

We used the multidetector coronary computed tomography data collected from subjects with type 2 diabetes who did not have a history of cardiovascular disease or angina symptoms. HbA1c measurements preceding the date of cardiac imaging were retrospectively collected, and intraindividual SD (HbA1c-SD), CV and adjusted SD of HbA1c measurements were calculated. Subclinical coronary atherosclerosis was defined as calcium score >400 without any cardiac symptoms.

RESULTS

A total of 595 subjects were categorized according to the median value of each HbA1c variability indicators. The prevalence of subclinical coronary atherosclerosis was higher in higher HbA1c variability group compared with lower HbA1c variability group. Multivariable logistic regression analysis showed that higher HbA1c-SD and -CV were associated with the presence of subclinical coronary atherosclerosis, independent of mean HbA1c level in subjects with diabetes duration ≤10 years (OR [95% CI]; HbA1c-SD, 2.894 [1.105-7.584]; HbA1c-CV, 2.540 [1.022-6.316]).

CONCLUSIONS

Long-term stabilization of blood glucose level might be important in preventing subclinical coronary atherosclerosis in subjects with earlier period of type 2 diabetes.

The association between glycemic variability and diabetic cardiovascular autonomic neuropathy in patients with type 2 diabetes

Background

It is presently unclear whether glycemic variability is associated with diabetic cardiovascular autonomic neuropathy (CAN). The aim of this study was to examine whether short- and/or long-term glycemic variability (GV) contribute to CAN.

Methods

A total of 110 patients with type 2 diabetes who underwent three-day continuous glucose monitoring (CGM) completed five standardized autonomic neuropathy tests. Short-term GV was measured by the standard deviation (SD), coefficient of variation (CV) of glucose, and the mean amplitude of glycemic excursions (MAGE) in CGM. HbA1c variability was calculated from the intrapersonal SD, adjusted SD, and CV of serial HbA1c over 2-year period. CAN was defined as the presence of at least two abnormal parasympathetic function tests. The severity of CAN was evaluated by total scores of five autonomic function tests.

Results

In univariate analysis, not only SD and CV in CGM but also all parameters of HbA1c variability were significantly higher in the patients with CAN (n = 47, 42.7 %) than in those without CAN. In multivariate analysis, CV (Odds ratio [OR] 1.07, 95 % confidence interval [CI] 1.01–1.13; p = 0.033), but neither SD nor MAGE in CGM, independently correlated with the presence of CAN. All parameters of HbA1c variability, such as SD of HbA1c (OR 12.10 [95 % CI 2.29–63.94], p = 0.003), adjusted SD of HbA1c (OR 17.02 [95 % CI 2.66–108.86], p = 0.003), and log CV of HbA1c (OR 24.00 [95 % CI 3.09–186.48], p = 0.002), were significantly associated with the presence of CAN. The patients with higher HbA1c variability had an increased risk of advanced CAN.

Conclusion

CV in CGM and all parameters of HbA1c variability were independently associated with the presence of CAN in patients with inadequately controlled type 2 diabetes requiring CGM.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0233-0) contains supplementary material, which is available to authorized users.

Cardiovascular events and all-cause mortality in a cohort of 57,946 patients with type 2 diabetes: associations with renal function and cardiovascular risk factors

Background

Diabetes and chronic kidney disease (CKD) are independent predictors of death and cardiovascular events and their concomitant prevalence has increased in recent years. The aim of this study was to characterize the effect of the estimated glomerular filtration rate (eGFR) and other factors on the risk of death and cardiovascular events in patients with type 2 diabetes.

Methods

A cohort of 57,946 patients with type 2 diabetes who were aged 20–89 years in 2000–2005 was identified from The Health Improvement Network, a UK primary care database. Incidence rates of death, myocardial infarction (MI), and ischemic stroke or transient ischemic attack (IS/TIA) were calculated overall and by eGFR category at baseline. eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) study equation. Death, MI and IS/TIA cases were detected using an automatic computer search and IS/TIA cases were further ascertained by manual review of medical records. Hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) for death, MI, and IS/TIA associated with eGFR category and other factors were estimated using Cox regression models adjusted for potential confounders.

Results

Overall incidence rates of death (mean follow-up time of 6.76 years), MI (6.64 years) and IS/TIA (6.56 years) were 43.65, 9.26 and 10.39 cases per 1000 person-years, respectively. A low eGFR (15–29 mL/min) was associated with an increased risk of death (HR: 2.79; 95% CI: 2.57–3.03), MI (HR: 2.33; 95% CI: 1.89–2.87) and IS/TIA (HR: 1.77; 95% CI: 1.43–2.18) relative to eGFR ≥ 60 mL/min. Other predictors of death, MI and IS/TIA included age, longer duration of diabetes, poor control of diabetes, hyperlipidemia, smoking and a history of cardiovascular events.

Conclusions

In patients with type 2 diabetes, management of cardiovascular risk factors and careful monitoring of eGFR may represent opportunities to reduce the risks of death, MI and IS/TIA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0204-5) contains supplementary material, which is available to authorized users.

Treatment-dependent and treatment-independent risk factors associated with the risk of diabetes-related events: a retrospective analysis based on 229,042 patients with type 2 diabetes mellitus

BACKGROUND

The aim of this study was to analyse which factors predict the real-world macro-/microvascular event, hospitalisation and death risk in patients with type 2 diabetes mellitus. Furthermore, we aimed to investigate whether there exists both an under- and over-treatment risk of these patients.

METHODS

We used a German claims/clinical data set covering the years 2010-12. Diabetes-related events were defined as (1) macro-, (2) microvascular events leading to inpatient hospitalisation, (3) other hospitalisations with type 2 diabetes mellitus as main diagnosis, (4) all-cause death and (5) a composite outcome including all event categories 1-4. Factors associated with event risk were analysed by a Kaplan-Meier curve analysis and by multivariable Cox regression models.

RESULTS

229,042 patients with type 2 diabetes mellitus (mean age 70.2 years; mean CCI 6.03) were included. Among factors that increased the event risk were patients' age, male gender, the adapted Charlson Comorbidity Index, the adapted Diabetes Complication Severity Index, previous events, and number of prescribed chronic medications. For systolic blood pressure/HbA1C, a double-J/U-curve pattern was detected: HbA1C of 6-6.5% (42-48 mmol/mol) and systolic blood pressure of 130-140 mmHg (17.3-18.7kPa) were associated with the lowest event risk, values below/above that range were associated with higher risk. However, this pattern was mainly driven by the death risk and was much less clearly observed for the macrovascular/microvascular/hospitalization risk and for young/less comorbid patients.

CONCLUSIONS

Both blood pressure and HbA1C seem to be very important treatment targets, especially in comorbid old patients. It is of particular clinical importance that both over- and under-treatment pose a threat to patients with type 2 diabetes mellitus.

Relationship of HbA1c variability, absolute changes in HbA1c, and all-cause mortality in type 2 diabetes: a Danish population-based prospective observational study

OBJECTIVE

We assessed the relationship of mortality with glycated hemoglobin (HbA1c) variability and with absolute change in HbA1c.

DESIGN

A population-based prospective observational study with a median follow-up time of 6 years.

METHODS

Based on a validated algorithm, 11 205 Danish individuals with type 2 diabetes during 2001-2006 were identified from public data files, with at least three HbA1c measurements: one index measure, one closing measure 22-26 months later, and one measurement in-between. Medium index HbA1c was 7.3%, median age was 63.9 years, and 48% were women. HbA1c variability was defined as the mean absolute residual around the line connecting index value with closing value. Cox proportional hazard models with restricted cubic splines were used, with all-cause mortality as the outcome.

RESULTS

Variability between 0 and 0.5 HbA1c percentage point was not associated with mortality, but for index HbA1c ≤8% (64 mmol/mol), a variability above 0.5 was associated with increased mortality (HR of 1 HbA1c percentage point variability was 1.3 (95% CI 1.1 to 1.5) for index HbA1c 6.6-7.4%). For index HbA1c≤8%, mortality increased when HbA1c declined, but was stable when HbA1c rose. For index HbA1c>8%, change in HbA1c was associated with mortality, with the lowest mortality for greatest decline (HR=0.9 (95% CI 0.80 to 0.98) for a 2-percentage point decrease).

CONCLUSIONS

For individuals with an index HbA1c below 8%, both high HbA1c variability and a decline in HbA1c were associated with increased mortality. For individuals with index HbA1c above 8%, change in HbA1c was associated with mortality, whereas variability was not.

Assessment of the association between glycemic variability and diabetes-related complications in type 1 and type 2 diabetes

Chronic hyperglycemia is the main risk factor for the development of diabetes-related complications in both type 1 and type 2 diabetes, but it is thought that frequent or large glucose fluctuations may contribute independently to diabetes-related complications. A systematic literature review was performed using the PubMed, EMBASE and Cochrane Library databases with searches limited to studies published from June 2002 to March 2014, in English and including ≥50 patients. Twenty eight articles were included in the final review. Eighteen studies reported the association between glucose variability and diabetes-related complications exclusively in type 2 diabetes. A positive association between increased variability and microvascular complications and coronary artery disease was consistently reported. Associations between glucose variability and other macrovascular complications were inconsistent in type 2 diabetes. Seven studies examined the association between glucose variability and complications exclusively in type 1 diabetes. Increased glucose variability appears to play a minimal role in the development of micro- and macrovascular complications in type 1 diabetes. Consistent findings suggest that in type 2 diabetes glucose variability is associated with development of microvascular complications. The role of increased glucose variability in terms of microvascular and macrovascular complications in type 1 diabetes is less clear; more data in are needed.

Chronic kidney disease in type 2 diabetes: lessons from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study

The Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study is an ongoing observational survey that examines the role of estimated glomerular filtration rate (eGFR) as an independent predictor of cardiovascular and renal outcomes in 15,773 Italian subjects with type 2 diabetes. The analysis of data collected at the enrollment visit provided a picture of chronic kidney disease (CKD) and its association with other complications, risk factors for cardiovascular disease (CVD) and treatments in a large contemporary cohort. Main results of this analysis were that (a) non-albuminuric renal impairment is the predominant clinical phenotype in patients, particularly women, with reduced eGFR; (b) concordance between CKD and diabetic retinopathy is low, with only a minority of patients with renal dysfunction presenting with any or advanced retinal lesions; (c) the non-albuminuric form is associated with a significant prevalence of CVD, especially at the level of the coronary vascular bed; (d) CKD is associated with hemoglobin (Hb) A1c variability more than with average HbA1c, whereas retinopathy and CVD are not; (e) in elderly individuals with moderate-to-severe eGFR reduction, use of agents which are not recommended, such as sulphonylureas and metformin, is still frequent; and (f) though complications are generally more prevalent in men (except non-albuminuric renal impairment) women show a less favorable CVD risk profile and achieve therapeutic targets to a lesser extent than men, despite the fact that treatment intensity is not lower. These data update existing information on the natural history of CKD in patients with type 2 diabetes.