Mechanism Underlying Beta-cell Failure in Obese African Americans With History of Hyperglycemic Crises

Study Summary

Obesity is common in African American (AA) patients with newly diagnosed diabetes who present with diabetic ketoacidosis (DKA). Despite the presentation with severe symptoms of insulinopenia and ketoacidosis, clinical and immunogenetic observations indicate that most obese AA patients with DKA have type 2 diabetes. In such patients, previous studies reveal that: a) at presentation, obese AA patients with DKA have markedly decreased pancreatic insulin secretion, lower than in obese non-DKA patients admitted with comparable hyperglycemia, but significantly greater than in lean patients with DKA; b) aggressive diabetic management results in significant improvement in beta-cell function and insulin sensitivity sufficient to allow discontinuation of insulin therapy within 3 months of follow-up. Based on these observations the researchers conclude that similar to obese patients with hyperglycemia, most obese AA with DKA have type 2 diabetes, and that although defects in both insulin secretion and insulin action are present, transient b-cell failure is the primary defect in the development of ketoacidosis.

Primary Outcome

An arginine stimulation test was used to evaluate beta-cell function and insulin secretion. Increased glucose in the blood causes insulin to be released, beginning with a spike in insulin in the first 10 minutes and plateauing 2 to 3 later. Diminished first-phase insulin release is an early indicator of beta-cell dysfunction. Two sequential arginine stimulation tests were performed, the first set before and the second after completion of the 20-hour dextrose infusion. The first-phase insulin rel

Interventions

• DRUG Intralipid 20%
• DRUG Glucose infusion