Characteristics of adult- compared to childhood-onset type 1 diabetes.

Aims: To compare diagnosis characteristics, diabetes management and comorbidities in a population diagnosed with type 1 diabetes in childhood with those in a similar population diagnosed in adulthood to identify disease differences related to the age of diabetes onset.

Methods: This analysis was performed using the T1D Exchange Clinic Registry, a cross-sectional survivor cohort. Retrospectively collected characteristics were compared across the following age-at-diagnosis groups: <10, 10-17, 18-24, 25-39 and ≥40 years.

Results: The entire cohort included 20 660 participants [51% female, median (interquartile range) age 18 (14-36) years, 82% non-Hispanic white]. Diabetic ketoacidosis at diagnosis was more common among those with onset in childhood. Participants diagnosed as adults were more likely to be overweight/obese at diagnosis and to have used oral agents preceding type 1 diabetes diagnosis (57%). Current insulin pump use was less frequent in participants diagnosed at older ages. Current glycaemic control, measured by HbA , insulin requirements and use of a continuous glucose monitor were not different by age at diagnosis. Coeliac disease was the only comorbidity that was observed to have a different frequency by age at diagnosis, being more common in the participants diagnosed at a younger age.

Conclusions: These results show differences and similarities between type 1 diabetes diagnosed in childhood vs adulthood; notably, there was a tendency for there was a higher frequency of diabetic ketoacidosis at onset in children and a higher frequency of use of oral antidiabetes agents in adults. The data indicate that there is little distinction between the clinical characteristics and outcomes of type 1 diabetes diagnosed in childhood vs adulthood. Optimizing glycaemic control remains a challenge in all age groups, with lower use of insulin pumps impacting those diagnosed as adults.