Eighteen‐Year Incidence, Health Outcomes and Costs Associated With Diabetic Ketoacidosis at Diagnosis of Type 1 Diabetes in Children in NSW, Australia

<b>Aim:</b> Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 diabetes (T1D). We determined the incidence, trends, cost and characteristics of children with and without DKA at T1D diagnosis and association with DKA readmissions. <b>Methods:</b> Children aged <16 years with T1D and residing in New South Wales, Australia, were identified from population-based hospital records (Admitted Patient Data Collection; APDC) for 2002-2019. Diagnoses of T1D and DKA were identified using ICD10 codes. Costs were determined using the 'Australian Refined-Diagnosis Related Group' (AR-DRG) code multiplied by the cost weight and National Efficient Price for the admission year. Associations were assessed using Chi-squared analyses and multivariate regression. <b>Results:</b> A total of 5832 children with T1D were identified, and 36% had DKA at diagnosis. The proportion with DKA at diagnosis was 34.4% in 2002-2003 and 41.0% in 2018-2019, with limited evidence to support a meaningful change over time (Cochrane-Armitage test-for-trend, <i>p</i>=0.062). DKA at diagnosis was associated with age <2 years, lower socio-economic status (SES) and rural/regional areas. DKA at diagnosis was also associated with an increased risk of readmission(s) for DKA (odds ratio [OR]: 1.35 [95% confidence interval [CI] 1.23, 1.49]). DKA doubled the costs/person, considering all available follow-up ($20,571 [interquartile range: $10,825, $37,845] vs. $9743 [$4980, $18,287]). <b>Conclusion:</b> DKA at diagnosis of T1D is a common and expensive health issue in Australia, with the rate of DKA at diagnosis not improving over the last two decades. Effective strategies are needed to improve health outcomes and reduce the economic burden.