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A tricky transition: when adolescents with type 1 diabetes move from paediatric to adult care

31st August 2023

A new study, based on type 1 diabetes audit data and reported in Diabetes Care, shows that failure to engage with services, hyperglycaemia and diabetic ketoacidosis peak in late adolescence. Therefore, innovative approaches to optimising glycaemia during the transition from paediatric to adult care are needed to avoid later-life complications. Dr Susan Aldridge reports. 

In young people who have type 1 diabetes, hyperglycaemia increases during adolescence and continues to do so as they transition to adult services. Data from the T1D Exchange Clinical Network confirm this and their 2016-2018 report shows that glycaemic control in those aged 15 to 18 years has deteriorated further, despite increased use of diabetes technology.  

It is generally assumed that it is the transition from paediatric to adult services at the age of 16 to 18 years, with changes in continuity and support, which leads to hyperglycaemia at this stage of life. There are also personal psychological issues and the influence of growth-related hormonal change on insulin requirements to consider. Whatever the cause, even these few years of hyperglycaemia can have long-term consequences, as seen from the follow-up of the Diabetes Control and Complications Trial.

In a new study, Naomi Holman at Imperial College London and colleagues looked at data from diabetes audits in England and Wales to investigate the age-related changes in HbA1c measurement, HbA1c levels and hospital admissions for diabetic ketoacidosis (DKA) in children and young people.

Exploring the age-related trajectory of hyperglycaemia

The National Diabetes Audit (NDA) for England and Wales collects data on people of all ages with a diabetes diagnosis from primary care records and adult specialist diabetes services. Each audit includes data for a 15-month period from 1 January to 31 March in the following year. Meanwhile, the National Paediatric Diabetes Audit (NPDA) collects data on children and young people from paediatric diabetes services in England and Wales for a 12-month time period from 1 April to 31 March in the following year. 

The researchers identified sequential cohorts of people with type 1 diabetes aged between five and 30 years from the 2017/2018, 2018/2019 and 2019/2020 data collections of the NDA and NPDA, from which they created a pooled cohort of 93,125 individuals. Then, for each year of age, the latest HbA1c measurement was identified and recorded, along with hospital admissions for DKA. 

The existence of an HbA1c record was used as a measure of clinic attendance and engagement with health services. The proportion of records lacking an HbA1c measurement was low (around 5%) up to age 16 and then it rose rapidly, peaking at 22.3% at age 21 for men and 17.3% at age 19 to 20 years for women. It then fell gradually to 17.9% for men and 13.1% for women at the age of 30. This reflects a peak in lack of engagement with services around the ages of 19 to 21, which never falls back to the level achieved in childhood.  

As has been previously observed, HbA1c rises with age, peaking in young adulthood, then falling again. At the age of nine, median HbA1c was 60 mmol/mol for males and 61 mmol/mol for females, peaking at age 19 at 72 mmol/mol for young men and 74 mmol/mol for young women. By the age of 39, it had fallen to 68 mmol/mol for men and 66 mmol/mol for women. Between the ages of 16 and 22 years, median HbA1c was consistently higher for women than men. 

When it came to glycaemic control, those aged 20 had the lowest proportion reaching a target of 58 mmol/mol or lower. And the greatest proportion of those with a very high HbA1c (more than 86 mmol/mol) was among young men aged 17 (31.4%) and young women aged 18 (35.8%). These age-related patterns persisted after adjustment for ethnicity, social deprivation and duration of diabetes. 

Finally, annual prevalence of one or more hospital admissions for DKA rose from 2% for boys and 1.4% for girls at the age of six, to a peak of 7.9% at age 19 for young men and 12.7% at age 18 for young women. After this, prevalence fell and, at age 30, it was 4.3% for men and 5.4% for women. Each year from the age of nine, the proportion of females with one or more annual hospitalisations for DKA was significantly higher than in males.

A significant drop in attendance

This analysis of over 93,000 individuals in England and Wales highlights the changes that occur when children with type 1 diabetes pass through adolescence to early adulthood. We’ve learned that almost all children have annual records for HbA1c – only 5% do not – reflecting faithful attendance at clinic. When they transition to adult services between the ages of 16 and 20, this proportion drops to around 80%. Median HbA1c, along with hospitalisation for DKA, starts to rise earlier but peaks around the time of transition. It then decreases again, but never goes back to childhood levels. 

So the HbA1c upward trend starts before, and continues after, the transition period. This hyperglycaemia pattern reflects that found in the SWEET project, which compiled data on 66,418 individuals with type 1 diabetes from 22 centres across 19 countries. It found that, from 2016 to 2018, HbA1c rose steadily from the age of six to 18 years. The scale in the rise of HbA1c from age nine to 18 years was 12 mmol/mol for males and 11 mmol/mol for females, and is similar to the 11 mmol/mol increase in HbA1c reported in another study for a combined cohort of individuals living in Germany or Austria and the US. 

The sudden increase at age 17 to 19 years in those lacking annual HbA1c records suggests a dramatic reduction in attendance at clinic at the time of changing provision from paediatric to adult. This age is also a time of increasing psychological and social pressures – leaving home for university, for instance. Adolescence is a time of profound psychological change for all young people and the more so if they have to manage a chronic condition like diabetes. The need for continual self-care is relentless and can create a considerable burden. Both very high HbA1c levels and DKA have been associated with insulin omission and psychological stress. An additional personal and clinical challenge is the effects of the surge in puberty-associated growth hormones. This demands physiologically matched adjustments of insulin, which will only add to the burden. 

While this study was not designed to identify the underlying reasons for lack of engagement, the authors suggest that it is likely due to a combination of personal and health-service factors. Whatever the reasons, this lack of engagement in late adolescence is concerning – research shows that people with type 1 diabetes for whom routine care processes have not been recorded are at increased risk of future morbidity and mortality. This is particularly so for those with the highest HbA1c levels and repeated admissions for DKA. 

This study found greater adverse changes among young women with type 1 diabetes. They were less likely to reach a glycaemic target of 58 mmol/mol and more likely to have an HbA1c of more than 86 mmol/mol. And, between the ages of 15 and 25, they were more likely to have at least one episode of DKA, compared with men of the same age. One reason for this inequality might be the higher prevalence of disordered eating among women. Psychological and societal pressures, including approaches to body image and peer pressure, may play out differently between men and women in this age group. 

The authors point out that this new study may even underestimate problematic hyperglycaemia among children and young people. The data comes from routine health records, which means that it is limited to those individuals who are actually engaging with health services. It therefore misses those who are potentially at greatest risk. The peak age for highest HbA1c coincides with the peak age for lack of records. One-third of the cohort had HbA1c of 86 mmol/mol or more at a time when another fifth had not even had their HbA1c recorded. While we can’t know for sure, it is likely that non-attenders have high HbA1c. So the scale of the increase in HbA1c in the late teens might be even greater than that recorded in this study. 

In conclusion, these findings point to the need for novel approaches to the support of children and young adults with type 1 diabetes. The aim should be to flatten the rise in HbA1c during the teenage years and reduce the peak in DKA admissions that occurs around the same time. It is clear from this study that improved, innovative, well-resourced and age-appropriate service designs oriented to deliver optimal diabetes care over the course of adolescence to young adulthood are warranted.

To read this paper, go to Holman N, Woch E, Dayan C, Warner J, Robinson H, Young B, Elliott J. National trends in hyperglycaemia and diabetic ketoacidosis in children, adolescents and young adults with type 1 diabetes: a challenge due to age of stage of development or is new thinking about service provision needed? Diabetes Care 2023; 46(7): 1404–1408.

To learn more about how to manage patients after the transition into adult care, enrol on the EASD e-Learning course ‘Management of type 1 diabetes in adults’.

Any opinions expressed in this article are the responsibility of the EASD e-Learning Programme Director, Dr Eleanor D Kennedy.