Presence or absence of a known diabetic ketoacidosis precipitant defines distinct syndromes of "A-β+" ketosis-prone diabetes based on long-term β-cell function, human leukocyte antigen class II alleles, and sex predilection.

Abstract Ketosis-prone diabetes (KPD) is heterogeneous. Longitudinal follow-up revealed that patients with "A- β +" KPD (absent autoantibodies and preserved β -cell function) segregated into 2 subgroups with distinct evolution of β -cell function and glycemic control. Generalized linear analysis demonstrated that the variable that most significantly differentiated them was presence of a clinically evident precipitating event for the index diabetic ketoacidosis (DKA). Hence, we performed a comprehensive analysis of A- β + KPD patients presenting with "provoked" compared with "unprovoked" DKA. Clinical, biochemical, and β -cell functional characteristics were compared between provoked and unprovoked A- β + KPD patients followed prospectively for 1 to 8 years. Human leukocyte antigen class II allele frequencies were compared between these 2 groups and population controls. Unprovoked A- β + KPD patients (n = 83) had greater body mass index, male preponderance, higher frequency of women with oligo-/anovulation, more frequent African American ethnicity, and less frequent family history of diabetes than provoked A- β + KPD patients (n = 64). The provoked group had higher frequencies of the human leukocyte antigen class II type 1 diabetes mellitus susceptibility alleles DQB1*0302 (than the unprovoked group or population controls) and DRB1*04 (than the unprovoked group), whereas the unprovoked group had a higher frequency of the protective allele DQB1*0602. β -Cell secretory reserve and glycemic control improved progressively in the unprovoked group but declined in the provoked group. The differences persisted in comparisons restricted to patients with new-onset diabetes. "Unprovoked" A- β + KPD is a distinct syndrome characterized by reversible β -cell dysfunction with male predominance and increased frequency of DQB1*0602, whereas "provoked" A- β + KPD is characterized by progressive loss of β -cell reserve and increased frequency of DQB1*0302 and DRB1*04. Unprovoked DKA predicts long-term β -cell functional reserve, insulin independence, and glycemic control in KPD.