Diabetic Ketoacidosis at Diagnosis is Associated With Adverse Long‐Term Glycaemic Trajectories and Retinopathy in Adult‐Onset Type 1 Diabetes. A Single‐Centre Retrospective Cohort Study
Riccardo Maria Pollis, Federico Boscari, Damiano Furlanetto, Cristina Bittante, Maria Cristina Crepaldi, Monica Vedovato, Daniela Bruttomesso, Alberto Maran, Benedetta Maria Bonora, Mario Luca Morieri, Gian Paolo FadiniABSTRACT
Aims
The long‐term significance of diabetic ketoacidosis (DKA) at the diagnosis of adult‐onset type 1 diabetes (T1D) is poorly understood. We investigated the association between DKA at diagnosis and long‐term outcomes.
Methods
In this retrospective study, we analysed adults with T1D diagnosed at age ≥ 18 years who attended a single tertiary diabetes centre between 2000 and 2025. Participants were classified according to the presence or absence of DKA at diagnosis. Longitudinal changes in HbA1c were analysed using mixed models. Incident chronic complications were evaluated using Cox regression models.
Results
Among 517 adults with T1D (47.2% women), 112 (21.7%) presented with DKA at diagnosis. The frequency of DKA at diagnosis increased from 13.2% in 2000–2008 to 34.6% after 2016 ( p < 0.001). During a median (IQR) follow‐up of 9.3 (3.5–15.5) years after cohort entry, individuals presenting with DKA had persistently higher HbA1c levels than those without DKA, with an adjusted between‐group difference of 0.37% (95% CI 0.20, 0.53; p < 0.001). When data were aligned to the diabetes onset date, the estimated mean difference was 0.66% ( p < 0.001). In exploratory analyses, DKA at diagnosis was associated with a higher incidence of retinopathy (HR 1.61; 95% CI 1.02–2.55; p = 0.041). The association was confirmed after accounting for delayed cohort entry and was attenuated by adjusting for mean HbA1c during follow‐up.
Conclusions
Among individuals with adult‐onset T1D attending a tertiary diabetes clinic, DKA at diagnosis was associated with persistently less favourable glycaemic control during long‐term follow‐up. Interpretation is limited by the single‐centre retrospective design and delayed cohort entry.