Identifying Diabetic Ketoacidosis Encounters at Diagnosis Among Children with Type 1 Diabetes in Claims Data

Among 728 Colorado children newly diagnosed with type 1 diabetes between 2014 and 2019, 56% had diabetic ketoacidosis (DKA), a life-threatening complication of untreated diabetes, at diagnosis, but ICD-based billing code algorithms inconsistently identified these cases in claims: a strict definition requiring both DKA and type 1 diabetes codes missed 37% of true cases, while a broader definition captured 89% but misclassified more children without DKA. These findings suggest claims-based algorithms likely undercount DKA at diagnosis, warranting sensitivity analyses in future research.