Influence of age at diagnosis on glycaemic control evolution in patients with type 1 diabetes

The objective of this study was to describe the relationship between age at onset, with no age limits, and glycaemic control evolution from the time of onset in patients with type 1 diabetes (T1D).

This observational retrospective follow-up study included 716 patients with T1D onset between 1990 and 2008 treated at the Navarre Hospital Complex. The mean (SD) follow-up lasted 10.1 (5.3) years. Information on their HbA(1c) levels was collected at onset and every year thereafter. Generalized additive mixed models and linear models were used, with patients' annual HbA1c levels as the response variable and the number of years since onset together with age at onset as covariates.

The evolution of glycaemic control is not linear and differs across all age groups. Children reach their highest values in adolescence, while patients with onset at ages 10-15 years stabilize their HbA(1c) values after 7 or 8 years. In adults, it is notable that an age of onset ≥ 45 years is associated with the worst control.

A non-linear increase in HbA(1c) levels can be observed from the time of T1D diagnosis, with significant differences across all age groups.