A patient with ketosis-prone type 2 diabetes showing nearly normalized glucose tolerance after recovery from severe diabetic ketoacidosis.

Unprovoked A-β+ ketosis-prone type 2 diabetes (KPD) is characterized by the sudden onset of diabetic ketosis/ketoacidosis (DK/DKA) without precipitating factors, negative anti-islet autoantibodies ("A- "), and preservation of β-cell function ("β+ ") after recovery from DKA using insulin therapy. However, there have been few reports on glucose tolerance after recovery. We present a case of KPD with nearly normalized glucose tolerance after recovery from severe DKA. A 41-year-old obese woman first presented with unprovoked severe DKA, i.e., ketonuria, plasma glucose 570 mg/dL, pH 7.18, and HCO₃ ^- 5.2 mmol/L, without anti-islet autoantibodies. She achieved insulin-free glycemic remission after recovery from DKA, leading to the diagnosis of KPD. Thereafter, 75 g oral glucose tolerance test showed impaired fasting glucose and time-in-range using intermittently scanned continuous glucose monitoring was 97% without medication. These findings suggest that, despite the initial severe DKA, some patients with KPD might achieve normalized glucose tolerance after recovery. The similar onset patterns of DKA necessitates appropriately distinguishing KPD from acute-onset type 1B (idiopathic) diabetes.

Supplementary information: The online version contains supplementary material available at 10.1007/s13340-022-00599-6.