This study aimed to assess the clinical severity and risk factors of diabetic ketoacidosis (DKA) at type 1 diabetes (T1D) diagnosis in children under 18 years in Greater Poland from 2006 to 2023, including temporal trends and the impact of COVID-19.

A retrospective cross-sectional study.

Greater Poland Province, Poland.

The study cohort comprised 2432 European Caucasian children (boys: 1335) aged 0–18 years with newly diagnosed T1D admitted to one hospital between 2006 and 2023.

DKA and its severity were classified according to the International Society for Pediatric and Adolescent Diabetes criteria. The multivariable analysis assessed the following risk factors for DKA at T1D diagnosis: age, sex, seasonality and the presence of T1D autoantibodies. Poisson regression models with a log link were used to assess the impact of the COVID-19 pandemic on monthly DKA cases at T1D onset, including time, pandemic period and their interaction as predictors.

DKA was diagnosed in 51.4% (1248) of newly diagnosed T1D patients, with 24.9% classified as mild, 14.4% as moderate and 12.1% as severe. Modest sex-related differences were observed, with DKA at T1D onset slightly more common in males than females (52.8% vs 47.2%). However, when comparing the DKA and non-DKA groups, a higher proportion of females presented with DKA (47.2%) than those without DKA (42.9%) (p=0.034). Children aged 0–2 years showed the highest DKA prevalence at T1D onset (76.4%), with a significant proportion experiencing severe DKA (33.6%). Factors like age, sex, season, glycaemia, glycated haemoglobin and autoantibodies did not independently predict DKA risk. The COVID-19 pandemic did not affect DKA rates at diagnosis.

The frequency of DKA is high, and its severity is substantial among children with newly diagnosed T1D in Greater Poland. Children aged 0–2 years are at the greatest risk of severe DKA at onset, underscoring the need for earlier recognition and intervention in this age group. Our findings emphasise the critical importance of increased awareness, education, point-of-care glucose testing, and targeted strategies such as T1D screening programmes to reduce the occurrence of DKA.