HbA1c variability is associated with increased mortality and earlier hospital admission in people with Type 1 diabetes

Higher HbA1c variability is associated with increased arterial stiffness in individuals with type 1 diabetes

BACKGROUND

Both long-term glycaemic variability and arterial stiffness have been recognized as cardiovascular risk factors. This study aims to investigate whether an association between these phenomena exists in individuals with type 1 diabetes.

METHODS

This cross-sectional study included 673 adults (305 men, 368 women) with type 1 diabetes and combined available retrospective laboratory data on HbA_1c from the preceding 10 years with outcome data on arterial stiffness and clinical variables from a comprehensive study visit. HbA_1c variability was calculated as adjusted standard deviation (adj-HbA_1c-SD), coefficient of variation (HbA_1c-CV) and average real variability (HbA_1c-ARV). As measures of arterial stiffness, carotid-femoral pulse wave velocity (cfPWV; n = 335) and augmentation index (AIx; n = 653) were assessed using applanation tonometry.

RESULTS

The study population had a mean age of 47.1 (± 12.0) years and a median duration of diabetes of 31.2 (21.2-41.3) years. The median number of HbA_1c assessments per individual was 17 (12-26). All three indices of HbA_1c variability were significantly correlated with both cfPWV and AIx after adjustment for sex and age (p < 0.001). In separate multivariable linear regression models, adj-HbA_1c-SD and HbA_1c-CV were significantly associated with cfPWV (p = 0.032 and p = 0.046, respectively) and AIx (p = 0.028 and p = 0.049, respectively), even after adjustment for HbA_1c-mean. HbA_1c-ARV was not associated with cfPWV or AIx in the fully adjusted models.

CONCLUSIONS

An association independent of HbA_1c-mean was found between HbA_1c variability and arterial stiffness, suggesting a need to consider multiple HbA_1c metrics in studies assessing cardiovascular risk in type 1 diabetes. Longitudinal and interventional studies are needed to confirm any causal relationship and to find strategies for reducing long-term glycaemic variability.

A systematic review and dose-response meta-analysis on the efficacy of dapagliflozin in patients with type 1 diabetes mellitus

Formulation of insulin analogs and its delivery are developed in over recent years but glycemic control in most patients with type-1 diabetes mellitus (DM) is not adequate yet. The aim of this meta-analysis is to evaluate the efficacy of dapagliflozin in patients with type-1 DM. The MEDLINE/PubMed, Scopus, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases were searched up to Aug 2020 to identify the potential literature. Random-effects model (DerSimonian and Laird method) was used to estimate the pooled effect size as weighted mean difference (WMD) with 95 % confidence interval (CI). Five randomized placebo-controlled trials with 11 arms were included in the quantitative analysis. The pooled results suggested a significant reduction in glycated hemoglobin A1C (HbA1C; WMD: -0.36 %, 95 % CI: -0.55, -0.18), body weight (WMD: -4.02 kg, 95 % CI: -4.78, -3.25), and total daily insulin dose (TDID; WMD: -10.36 %, 95 % CI: -13.42, -7.29), as well as an increase in 24-h urinary glucose excretion (24-h UGE; WMD: 90.02 g/24-h, 95 % CI: 72.96, 107.09) in dapagliflozin group compared to control group. Dose of dapagliflozin had a significant effect on body weight reduction (Coef = -3.7, p = 0.01) and 24-h UGE (coef = 0.85, p = 0.005). Pooled results of this meta-analysis identified a significant reduction in HbA1c levels, body weight, and TDID, and a substantial increase in 24-h UGE in patients who received dapagliflozin versus placebo.

Glycated hemoglobin variability and microvascular complications in patients with type 1 diabetes mellitus

OBJECTIVES

Glycated hemoglobin (HbA1c) has proven to be indicative in the development of microvascular complications. In this study, the contribution of HbA1c variability to microvascular complications was evaluated.

METHODS

Twenty-one cases with type 1 diabetes mellitus (T1DM) who developed microvascular complications and 39 cases without complications, that were similar in terms of gender, age of diagnosis, insulin treatment, insulin doses (U/kg), and mean HbA1c levels were included.

RESULTS

Mean age of T1DM diagnosis was 5.87 ± 3.93 years in the complication group and 4.63 ± 3.33 years in the control group. Nephropathy was detected in 17 cases, neuropathy in 8 cases, and retinopathy in 1 case. Nephropathy occurred at a mean age of 11.52 ± 4.12 years and neuropathy at 14.13 ± 5.68 years. The mean HbA1c during follow-up was similar in the group with complications and the control group (8.60 ± 0.63 vs. 8.84 ± 1.32). Adjusted HbA1c-standard deviation (SD) and HbA1c-variation coefficient (CV) values were 1.30 ± 0.65 and 14.36 ± 6.23 in the group with complications (p=0.014), and 0.91 ± 0.37 and 10.59 ± 4.01 in the control group (p=0.013). In the Receiver Operating Characteristic (ROC)-analysis for microvascular complications, the limit value HbA1c-CV was 11.99 (sensitivity: 61.9%, specificity: 71.9%). This value for HbA1c-SD was 0.9699 (sensitivity: 71.43%, specificity: 66.67%).

CONCLUSIONS

This study has shown that long-term fluctuations in HbA1c are associated with the development of microvascular complications in type 1 diabetes.

Glycemic variability: adverse clinical outcomes and how to improve it?

Glycemic variability (GV), defined as an integral component of glucose homoeostasis, is emerging as an important metric to consider when assessing glycemic control in clinical practice. Although it remains yet no consensus, accumulating evidence has suggested that GV, representing either short-term (with-day and between-day variability) or long-term GV, was associated with an increased risk of diabetic macrovascular and microvascular complications, hypoglycemia, mortality rates and other adverse clinical outcomes. In this review, we summarize the adverse clinical outcomes of GV and discuss the beneficial measures, including continuous glucose monitoring, drugs, dietary interventions and exercise training, to improve it, aiming at better addressing the challenging aspect of blood glucose management.

Structured education using Dose Adjustment for Normal Eating (DAFNE) reduces long-term HbA1c and HbA1c variability

AIMS

Previous evidence has demonstrated that participation in the Dose Adjustment for Normal Eating (DAFNE) education programme can reduce HbA_1c and severe hypoglycaemia in people with Type 1 diabetes. In a number of studies, increased HbA_1c variability has been associated with higher diabetic morbidity and mortality. No studies have examined the impact of structured education on HbA_1c variability in Type 1 diabetes.

METHODS

People with Type 1 diabetes who had attended DAFNE were identified for inclusion from the Scottish Care Information-Diabetes dataset. HbA_1c median and variability, expressed as coefficient of variation (CV) before and after DAFNE was calculated.

RESULTS

Some 1061 individuals participated in DAFNE education and 687 met the inclusion criteria. A significant median reduction in HbA_1c [-3.5 mmol/mol (-0.3%)] was seen at 12 months with a significant reduction [-1.5 mmol/mol (-0.1%)] still seen at 60 months of follow-up. HbA_1c variability as measured by CV was significantly lower during the post-DAFNE period: 0.08 (IQR 0.05-0.12) reduced to 0.07 (IQR 0.05-0.10); P = 0.002.

CONCLUSION

The data confirm that DAFNE participation improves glycaemic control in Type 1 diabetes with benefits being sustained for 5 years. This study is the first to demonstrate reduced HbA_1c variability after completion of structured education. This is new evidence of the beneficial impact of DAFNE on glycaemic profile.

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.