Type 1 diabetes management: is HbA1c an out-of-date measure?

HbA1c has been an established clinical measure of glucose control for diabetes since the late 1970s, but, like sideburns and flares, has HbA1c become a relic that has outstayed its welcome?

HbA1c tests measure glycosylated haemoglobin, which means how much glucose has ‘stuck’ to your red blood cells over the last 8-12 weeks.

The higher the levels of glucose in the blood over this time, the more glucose gets stuck to your red blood cells.

In this way, clinicians can get a rough idea of whether someone with diabetes (any type) has blood glucose levels that are higher than a target level. Some have questioned, however, whether HbA1c alone is still a useful measure to consider when assessing type 1 management as it can only give a sense of average glucose levels over time, not the ups and downs that many experience on a day to day basis.

‘Time in range’ and other measures

JDRF in the USA has spent two years working with clinicians, researchers, other funders, and people affected by type 1 diabetes to understand what we can measure beyond HbA1c; what else might be useful in order to understand the full story for someone managing their type 1 diabetes?

The results show that HbA1c, while useful, cannot capture the day-to-day variations in blood glucose levels and other complexities that make up life with type 1. With advancing technology, however, we can make use of increasing amounts of data to explore glucose level changes in more detail, such as time spent in range, or long periods of time avoiding hypos.

A published consensus statement summarising the findings suggests that other measurable outcomes should be considered when building a fuller picture of type 1 management, including hypoglycaemic and  hyperglycaemic events, time in range, and experience of diabetic ketoacidosis.

The research also identified a need for more nuance in defining hypo- and hyperglycaemia. Both states can range in severity, and the consensus statement makes a recommendation for a three level classification system for hypos and a two level classification for hyperglycaemia, ranging from mild and in need of action, to serious and requiring assistance.

Beyond the numbers – examining feelings

Discovery Days' families

Relying not just on numbers, but on physical and emotional feelings also reflects the fact that different people can experience different physical responses to the same glucose level.

The most important message that comes out of the research is that evaluation of type 1 management comes from more than just tests. Everyone with type 1 experiences the condition through a different lens, and the clinical and research world needs to shift to adapt to these different perspectives, and develop a more personalised approach to treatment and research.

To this end, the consensus statement highlights the importance of patient reported outcomes, or PROs. A PRO is any information given directly by someone living with a condition which is not interpreted through a clinician or test.

In short, researchers and clinicians must listen to how people with type 1 describe their experience of managing the condition, and consider this alongside the numbers. Only then can effective changes be made where needed.

So while we should not scrap HbA1c as part of type 1 care, as with 1970s fashion, we should be open up to newer trends and updated approaches to type 1 management.