First year national Swedish paediatric Hba1c data are at the level of several intervention studies: Results from a Swedish nationwide diabetes register study

Aims/hypothesis

To study the progression of HbA1c after diagnosis of type 1 diabetes in children and adolescents during 2010–2019 with emphasis on HbA1c nadir 3–6 months after onset.

Methods

Partial funding was secured for this study. The Swedish paediatric diabetes quality register SWEDIABKIDS has >95 % coverage of type 1 diabetes up to 18 years. A mixed model for repeated measurements was used to estimate differences in HbA1c between onset year periods.

Results

We followed 6,891 patients over two years from onset (48,292 HbA1c values). We found a gradual decrease in mean HbA1c 24 months after onset from 56.0 mmol/mol (7.28 %) in 2010/11 to 50.5 mmol/mol (6.77 %) in 2018/19, which is at the level of several recent intervention studies. The initial drop in HbA1c from onset until 3 and 6 months has become more pronounced in recent years. There was a significant positive correlation between HbA1c at 3 and 6 months with 12, 18 and 24 months. Percentage of severe hypoglycaemic coma was higher (5.1 % vs 3.4 %; p = 0.023) in 2010/2011 than 2018/2019, but the absolute risk of ketoacidosis was essentially unchanged, (1.5 % to 0.8 %, p = 0.110)

Conclusions/interpretation

There was a continuous decrease in HbA1c over the study period 2010–2019, which coincides in time with an increased use of diabetes technology and lowering the HbA1c target to 48 mmol/mol (6.5 %). The decrease in 2-year HbA1c was preceded by a lower HbA1c nadir, which may set the trajectories for coming HbA1c and be a modifiable factor for a long-term improvement in metabolic control.