A 74-year-old woman is admitted to the hospital in an obtunded condition. Her temperature is 37deg C, pulse is 95/ min, respirations are 22/min, and blood pressure is 90/60 mm Hg. She appears dehydrated and has poor skin turgor. Her serum glucose level is 872 mg/dL. Urinalysis shows 4+ glucosuria, but no ketones, protein, or blood. Which of the following factors is most important in the pathogenesis of this patient's condition?

A complication of type 2 diabetes mellitus is hyperosmolar, nonketotic coma. In type 2 diabetes mellitus, the fundamental defect is insulin resistance, leading to an eventual decrease in plasma insulin or a relative lack of insulin, but there is still enough insulin to prevent ketosis. The resulting hyperglycemia tends to produce polyuria, leading to dehydration, which increases the serum glucose level further. If not enough fluids are ingested, dehydration drives the serum glucose to very high levels. Glucokinase gene mutations can be present with maturity-onset diabetes of the young (MODY). The HLA-DR3/HLA-DR4 genotype is a predisposing factor for type 1 diabetes mellitus. Severe loss of beta cells with insulitis, which may be triggered by a viral infection, is a feature of autoimmune, or type 1, diabetes mellitus.