TiR and HbA1c
There is a good correlation between HbA1c and %TIR across a broad range of subjects (T1D and T2D), ages, and technologies across 18 studies
HbA1c has been used as gold standard for last 3 decades, but two people with the same HbA1c may actually have very different glucose variability e.g. one with high variability has many hyperglycaemic and hypoglycaemic episodes, whereas the other may have little variability does not
Why isn't HbA1c alone sufficient?
- HbA1c alone does not provide a comprehensive view of an individual’s glucose profile and variability nor take into account the conditions that affect HbA1c, such as anaemia and pregnancy
- HbA1c has been the gold standard for diagnosing diabetes and assessing glycaemic management for more than three decades
- HbA1c reflects the average plasma glucose over the previous 8–12 weeks
- Increasing levels of HbA1c (above the ADA recommended HbA1c of 7) are associated with increased risk of microvascular and cardiovascular diabetes complications and mortality
- Two people with the same HbA1c may actually have very different glucose variability e.g. one with high variability and therefore many hyperglycaemic and hypoglycaemic episodes, whereas the other may have little variability and therefore no hyperglycaemic and hypoglycaemic episodes
Time in Range: Time-in-range can capture these differences in a way HbA1c cannot.
How does TiR complement HbA1c?
TIR can be used as a metric for providing a more detailed view of an individual patients’ glycaemic control, predicting the risk of diabetes complications, and determining the outcome of clinical studies
- There is a good correlation between HbA1c and %TIR across a broad range of subjects (T1D and T2D), ages, and technologies across 18 studies
- For every absolute 10% change in %TIR, there was a ~0.8% (9 mmol/mol) reduction in HbA1c