New Insights into the Role of Visit-to-Visit Glycemic Variability and Blood Pressure Variability in Cardiovascular Disease Risk

Variability in Cardiometabolic Parameters and All-Cause and Cause-Specific Mortality in Older Adults: Evidence From 2 Prospective Cohorts

INTRODUCTION

The aim of this study is to assess the individual and joint associations of variability in multiple cardiometabolic parameters with mortality risk across older populations.

METHODS

A total of 51,551 Chinese elderly participants (aged ≥60 years) with ≥3 measurements of systolic blood pressure, visceral adiposity index, fasting blood glucose, and low-density lipoprotein cholesterol during 2018-2022 were included. Variability metrics included SD, coefficient of variation, average real variability, and variability independent of the mean (used in primary analysis). Participants were classified on the basis of the number of high-variability (highest quartile of variability) parameters into 4 categories: with 0, 1, 2, and 3-4 high-variability cardiometabolic parameters. Cox regression analyses were performed in 2024. Findings were then externally validated using the Health and Retirement Study (Waves 8-15).

RESULTS

Higher systolic blood pressure, visceral adiposity index, fasting plasma glucose, and low-density lipoprotein cholesterol variability were associated with greater all-, cardiovascular-, and other-cause mortality risk. Compared with those of subjects with no high-variability parameters measured as the variability independent of the mean, the hazard ratios (95% CI) of all-cause mortality were 1.30 (1.16, 1.44) for 1 parameter, 1.86 (1.66, 2.09) for 2 parameters, and 2.02 (1.75, 2.32) for 3-4 parameters. Consistent results were noted for cardiovascular-, cancer-, and other-cause mortality using other variability indices and in various sensitivity and subgroup analyses. These associations were validated in the Health and Retirement Study (n=1,991).

CONCLUSIONS

Increased variability in cardiometabolic parameters is associated with elevated risks of all-cause and cause-specific mortality among older adults in China. Reducing variability of these parameters could serve as a target to increase life expectancy in older populations.

HbA1c variability associated with dementia risk in people with type 2 diabetes

INTRODUCTION

Although poor glycemic control is associated with dementia, it is unknown if variability in glycemic control, even in those with optimal glycosylated hemoglobin A1c (HbA1c) levels, increases dementia risk.

METHODS

Among 171,964 people with type 2 diabetes, we evaluated the hazard of dementia association with long-term HbA1c variability using five operationalizations, including standard deviation (SD), adjusting for demographics and comorbidities.

RESULTS

The mean baseline age was 61 years (48% women). Greater HbA1c SD was associated with greater dementia hazard (adjusted hazard ratio = 1.15 [95% confidence interval: 1.12, 1.17]). In stratified analyses, higher HbA1c SD quintiles were associated with greater dementia hazard among those with a mean HbA1c < 6% (P = 0.0004) or 6% to 8% (P < 0.0001) but not among those with mean HbA1c ≥ 8% (P = 0.42).

DISCUSSION

Greater HbA1c variability is associated with greater dementia risk, even among those with HbA1c concentrations at ideal clinical targets. These findings add to the importance and clinical impact of recommendations to minimize glycemic variability.

HIGHLIGHTS

We observed a cohort of 171,964 people with type 2 diabetes (mean age 61 years). This cohort was based in Northern California between 1996 and 2018. We examined the association between glycosylated hemoglobin A1c (HbA1c) variability and dementia risk. Greater HbA1c variability was associated with greater dementia hazard. This was most evident among those with normal-low mean HbA1c concentrations.

Visit-to-Visit Glucose Variability, Cognition, and Global Cognitive Decline: The Multi-Ethnic Study of Atherosclerosis

CONTEXT

Higher visit-to-visit glucose variability (GV) is associated with dysglycemia and type 2 diabetes (T2D), key risk factors for cognitive decline.

OBJECTIVE

Evaluate the association of GV with cognitive performance and decline in racially/ethnically diverse older populations with and without T2D.

METHODS

We calculated the standard deviation of glucose (SDG), average real variability (ARV), and variability independent of the mean (VIM) among 4367 Multi-Ethnic Study of Atherosclerosis participants over 6 clinical examinations. Participants completed a cognitive assessment at the fifth examination, and a subset completed a second assessment 6 years later. We used multivariable linear regression to estimate the association of intraindividual GV with cognitive test scores after adjustments for cardiovascular risk factors and mean glucose level over the study period.

RESULTS

Two-fold increments in the VIM and SDG were associated with worse Cognitive Abilities Screening Instrument (CASI) performance, while two-fold increments in VIM and ARV were associated with worse Digit Symbol Coding test score. GV measures were not associated with change in CASI performance among 1834 participants with repeat CASI data 6 years later. However, among 229 participants with incident T2D, the SDG and VIM were associated with decline in CASI (-1.7 [95% CI: -3.1, -0.3] and -2.1 [-3.7, -0.5] points, respectively). In contrast, single-timepoint glucose and HbA1c were not associated with CASI decline among participants with or without incident T2D.

CONCLUSION

Higher visit-to-visit GV over 16 to 18 years is associated with worse cognitive performance in the general population, and with modest global cognitive decline in participants with T2D.

Attachment in close relationships and glycemic outcomes in children with type 1 diabetes

BACKGROUND

Our aim was to determine whether child attachment to parents, parent attachment style, and morning cortisol levels were related to diabetes outcomes measured by average glycated hemoglobin (HbA1c), HbA1c variability over 4 years and time in range (TIR) in children with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

101 children with T1D and one of their parents were assessed at baseline for child attachment (Child Attachment Interview; CAI) and parent attachment (Relationship Structures Questionnaire; ECR-RS). Serum samples were collected for cortisol measurements before the interviews. HbA1c levels were measured during a 4-year follow-up period at regular 3-monthly visits, and data for TIR were exported from blood glucose measuring devices. Multivariate linear regression models were constructed to identify independent predictors of glycemic outcomes.

RESULTS

More girls than boys exhibited secure attachment to their mothers. The results of the regression models showed that securely attached girls (CAI) had higher average HbA1c than did insecurely attached girls (B = -0.64, p = 0.03). In boys, the more insecure the parent's attachment style, the worse the child's glycemic outcome: the higher the average Hb1Ac (B = 0.51, p = 0.005), the higher the HbA1c variability (B = 0.017, p = 0.011), and the lower the TIR (B = -8.543, p = 0.002).

CONCLUSIONS

Attachment in close relationships is associated with glycemic outcomes in children with T1D, and we observed significant differences between sexes. A sex- and attachment-specific approach is recommended when treating children with less favorable glycemic outcomes. Special attention and tailored support should be offered to securely attached girls in transferring responsibility for diabetes care and at least to male children of insecurely attached parents to prevent suboptimal glycemic control. Further studies in larger samples and more daily cortisol measurements may help us better understand the links between stress response, attachment and T1D.

Visit-to-visit HbA1c variability is associated with aortic stiffness progression in participants with type 2 diabetes

BACKGROUND

Glycemic variability plays an important role in the development of cardiovascular disease (CVD). This study aims to determine whether long-term visit-to-visit glycemic variability is associated with aortic stiffness progression in participants with type 2 diabetes (T2D).

METHODS

Prospective data were obtained from 2115 T2D participants in the National Metabolic Management Center (MMC) from June 2017 to December 2022. Two brachial-ankle pulse wave velocity (ba-PWV) measurements were performed to assess aortic stiffness over a mean follow-up period of 2.6 years. A multivariate latent class growth mixed model was applied to identify trajectories of blood glucose. Logistic regression models were used to determine the odds ratio (OR) for aortic stiffness associated with glycemic variability evaluated by the coefficient of variation (CV), variability independent of the mean (VIM), average real variability (ARV), and successive variation (SV) of blood glucose.

RESULTS

Four distinct trajectories of glycated hemoglobin (HbA1c) or fasting blood glucose (FBG) were identified. In the U-shape class of HbA1c and FBG, the adjusted ORs were 2.17 and 1.21 for having increased/persistently high ba-PWV, respectively. Additionally, HbA1c variability (CV, VIM, SV) was significantly associated with aortic stiffness progression, with ORs ranging from 1.20 to 1.24. Cross-tabulation analysis indicated that the third tertile of the HbA1c mean and VIM conferred a 78% (95% confidence interval [CI] 1.23-2.58) higher odds of aortic stiffness progression. Sensitivity analysis demonstrated that the SD of HbA1c and the highest HbA1c variability score (HVS) were significantly associated with the adverse outcomes independent of the mean of HbA1c during the follow-up.

CONCLUSIONS

Long-term visit-to-visit HbA1c variability was independently associated with aortic stiffness progression, suggesting that HbA1c variability was a strong predictor of subclinical atherosclerosis in T2D participants.

Association between Variability of Metabolic Risk Factors and Cardiometabolic Outcomes

Despite strenuous efforts to reduce cardiovascular disease (CVD) risk by improving cardiometabolic risk factors, such as glucose and cholesterol levels, and blood pressure, there is still residual risk even in patients reaching treatment targets. Recently, researchers have begun to focus on the variability of metabolic variables to remove residual risks. Several clinical trials and cohort studies have reported a relationship between the variability of metabolic parameters and CVDs. Herein, we review the literature regarding the effect of metabolic factor variability and CVD risk, and describe possible mechanisms and potential treatment perspectives for reducing cardiometabolic risk factor variability.

Association Between Long-Term HbA1c Variability and Functional Limitation in Individuals Aged Over 50 Years: A Retrospective Cohort Study

BACKGROUND

As mean HbA1c provides incomplete information regarding glycemic variability, there has been considerable interest in the emerging association between glycemic variability and macrovascular events and with microvascular complications and mortality in adults with and without diabetes. However, the association between long-term glycemic variability, represented by visit-to-visit HbA1c variability, and functional limitations has not been clarified in previous literature. The present study aimed to explore the longitudinal association between long-term glycemic variability, represented by visit-to-visit HbA1c variability and functional limitations.

METHODS

This cohort study included adults aged over 50 years who participated in the 2006 to 2016 waves of the Health and Retirement Study. Physical functions, including mobility, large muscle function, activities of daily living (ADLs), and instrumental ADLs (IADLs), were assessed at baseline and every 2 years, and HbA1c levels were assessed at baseline and every 4 years. Visit-to-visit HbA1c variability was calculated using the HbA1c variability score (HVS) during the follow-up period. Generalized estimating equation models were used to evaluate the longitudinal association between HbA1c variability and functional limitations with adjustment for a series of confounders.

RESULTS

A total of 5,544 participants having three HbA1c measurements from 2006 to 2016, having two or more physical function measures (including one at baseline), and age over 50 years were included in this analysis. The mean age at baseline was 66.13 ± 8.39 years. A total of 916 (16.5%) participants had an HVS = 100, and 35.1% had an HVS = 50. The highest HVS category (HVS =100) was associated with increased functional status score (β = 0.093, 95% CI: 0.021-0.165) in comparison with the lowest HVS category (HVS = 0). Sensitivity analyses using the CV and SD of HbA1c as measures of variability showed similar associations between HbA1c variability and functional limitation. An incremental increase in HbA1c-CV (β = 0.630, 95% CI: 0.127-1.132) or HbA1c-SD (β = 0.078, 95% CI: 0.006-0.150) was associated with an increase in functional limitation in the fully adjusted model.

CONCLUSIONS

HbA1c variability was associated with heightened difficulty in performing functional activities over time after adjusting for mean HbA1c levels and multiple demographics and comorbidities. This study provides further evidence regarding the detrimental effect of HbA1c variability and highlights the significance of steady glycemic control.