Aims
The reported relationship between diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes (T1D) and long-term glycemic control varies between studies. We aimed firstly to characterise the association of DKA and its severity with long-term HbA1c in a large contemporary cohort, and secondly to identify other independent determinants of long-term HbA1c.
Methods
Participants were 7961 children and young adults diagnosed with T1D by age 30 years from 2000-2019 and followed prospectively in the Australasian Diabetes Data Network (ADDN) until 31/12/2020. Linear mixed effect models were used to study the relationship between HbA1c and other variables.
Results
DKA at diagnosis was present in 2647 (33.2%) participants. Over a median 5.6 (IQR 3.2, 9.4) years follow-up, participants with severe, but not moderate or mild, DKA at diagnosis had a higher mean HbA1c (+0.23%, 95% CI: 0.11, 0.28; p<0.001) compared to those without DKA. Use of continuous subcutaneous insulin infusion (CSII) was independently associated with a lower HbA1c over time than multiple daily injections (MDI) (-0.28%, 95% CI: -0.31, -0.25; p<0.001), and this relationship was more pronounced in participants with severe DKA at diagnosis. Indigenous status was associated with higher HbA1c (+1.37%, 95% CI: 1.15, 1.59; p<0.001), as was residing in postcodes of lower socioeconomic status (most versus least disadvantaged quintile +0.43%, 95% CI: 0.34, 0.52; p<0.001).
Conclusion
Severe DKA at diagnosis (but not moderate or mild) was associated with a marginally higher HbA1c over follow-up of ADDN children and young adults with T1D, an effect which was modified by use of CSII. Indigenous status and lower socioeconomic status were independently associated with higher HbA1c, and CSII with lower HbA1c, further emphasising the need for equity of access to health services and modern diabetes technology for all patients with T1D.