Objective: To analyse among adult Caucasian patients hospitalised for diabetic ketoacidosis the relative frequency of patients with type 2 diabetes and their characteristics.
Research design: A retrospective review of adult patients presenting with diabetic ketoacidosis was conducted between 1993 and 1996. Patients with typical type 1 diabetes were classified according to age of onset < 35 years, insulin-dependence and BMI < 25 kg/m2; patients who did not meet these criteria were further classified on the basis of a basal and stimulated C-peptide and the detection of antibodies to glutamic acid decarboxylase (GADA) and to islet cells (ICA).
Results: 43 patients presenting with an episode of diabetic ketoacidosis were divided into two groups, A and B. Group A consisted of 19 patients, 17 patients classified as patients with typical type 1 diabetes and 2 patients with diabetes post-pancreatectomy. The other patients were the subjects of our study (group B; n = 20, 4 lost to follow-up). 13 patients (65% of group B = B I) were diagnosed with type 1 diabetes (median basal C-peptide: 0.15 nmol/l) and 7 patients (35% of group B = B II) with type 2 diabetes (median basal C-peptide of 1 nmol/l). Higher body mass index (BMI), shorter duration of diabetes, smaller anion gap and worse glycaemic control were found to be significantly different between groups B I and II on admission (p < 0.05). After a median follow-up of 18 months, patients in group B II had a better metabolic control than those in B I and 5 of the 7 patients were treated without insulin.
Conclusion: Diabetic ketoacidosis is more common than previously thought in patients with type 2 diabetes, occurring in 16% of all cases. Distinctive features at presentation are the degree of acidosis, the duration of diabetes, BMI and HbA1c. However, the basal plasma C-peptide value remains the best discriminating factor.