Glycemic Variability and Cardiovascular Outcomes in Diabetes

Glycemic variability refers to fluctuations in blood glucose levels over time and has emerged as a critical dimension of metabolic control in diabetes beyond average measures such as haemoglobin A1c (HbA1c). Accumulating evidence links both short-term swings and long-term visit-to-visit variability with adverse cardiovascular outcomes. Mechanistic studies suggest that oscillating glucose levels provoke oxidative stress, endothelial dysfunction and inflammatory responses, thereby accelerating atherogenesis. Clinically, higher variability has been associated with increased rates of major adverse cardiovascular events, heart failure admissions and cardiovascular mortality across diverse patient populations, including those with established coronary disease and those at high risk. Incorporating metrics of variability alongside mean glucose indices may refine risk stratification and guide individualised therapy, emphasising the selection and timing of antihyperglycaemic agents to smooth glycaemic excursions. Ultimately, targeting both sustained hyperglycaemia and marked fluctuations offers a more comprehensive approach to cardiovascular risk reduction in diabetes.

Research from Nature Portfolio

A large retrospective cohort study of Chinese patients with type 2 diabetes evaluated whether visit-to-visit variability in fasting plasma glucose independently predicts all-cause mortality. Patients were stratified by quartiles of the coefficient of variation of fasting plasma glucose over one year and followed for up to seven years. While the variability measure was not uniformly predictive across the whole cohort, in patients with suboptimal overall control (mean glucose ≥7 mmol/L) higher variability was robustly associated with elevated mortality risk. This work underscored the importance of monitoring glucose stability, particularly in those who struggle to achieve target levels, and suggested that minimising day-to-day fluctuations might yield survival benefits.

Glycemic Variability and Cardiovascular Outcomes in Diabetes publication trend

The graph below shows the total number of articles in glycemic variability and cardiovascular outcomes in diabetes across all publications each year (not limited to Nature Index journals).

Technical terms

Glycemic variability: The degree of fluctuation in blood glucose levels over defined time frames, including short-term (day-to-day) and long-term (visit-to-visit) measures.

Haemoglobin A1c (HbA1c): A marker of average blood glucose over the preceding two to three months, expressed as a percentage.

Fasting plasma glucose (FPG): The blood glucose concentration measured after an overnight fast, used as a standard metric for glycaemic control.

Coefficient of variation (CV): A normalized measure of dispersion calculated as the standard deviation divided by the mean, often expressed as a percentage to quantify variability.

Major adverse cardiovascular events (MACE): A composite endpoint commonly including cardiovascular death, non-fatal myocardial infarction and non-fatal stroke, used to assess the safety and efficacy of interventions.

References

1. Fasting plasma glucose variability and all-cause mortality among type 2 diabetes patients: a dynamic cohort study in Shanghai, China. Scientific Reports (2016).
2. Long-term visit-to-visit glycemic variability as predictor of micro- and macrovascular complications in patients with type 2 diabetes: The Rio de Janeiro Type 2 Diabetes Cohort Study. Cardiovascular Diabetology (2018).
3. Day-to-day fasting glycaemic variability in DEVOTE: associations with severe hypoglycaemia and cardiovascular outcomes (DEVOTE 2). Diabetologia (2017).
4. Glycemic and lipid variability for predicting complications and mortality in diabetes mellitus using machine learning. BMC Endocrine Disorders (2021).