Comprises 10% to 20% of all cases of severe hyperglycemia. Most common in elderly with mild recent-onset diabetes mellitus. Mortality 40% to 50%.

Average age 60 years. Diabetes often unrecognized; few patients taking insulin.

Often precipitated by associated illness (chronic renal insufficiency, gram-negative pneumonia or sepsis, gastrointestinal hemorrhage, myocardial infarction, pulmonary embolism, subdural hematoma, stroke, pancreatitis, burns) or medical therapy (diuretic agents, corticosteroids, phenytoin, propranolol, cimetidine, diazoxide, chlorpromazine, loxapine, L-asparaginase, immunosuppressive agents, hyperalimentation, peritoneal dialysis, hemodialysis, cardiac surgery).