Over 50% of obese African-Americans (AA) presenting with newly diagnosed, severe hyperglycemia and/or unprovoked diabetic ketoacidosis (DKA) display clinical, metabolic, and immunogenetic features of type 2 diabetes. Prior studies indicate that these patients a) have markedly decreased insulin secretion and impaired insulin action at presentation, b) absent or low prevalence of beta-cell autoantibodies and c) are able to discontinue aggressive insulin therapy in ~70% of cases within 3 months of follow-up. These patients have been referred to as having ketosis-prone type 2 diabetes (KPDM).

Most patients with KPDM, however, experience a hyperglycemic relapse within a year of insulin discontinuation. Consequently, patients with "KPDM" are an ideal model to follow throughout their clinical course. The specific aims of this proposal are to 1) identify clinical, metabolic, and immunogenetic markers that alone, or in combination, are predictive of short- and long-term near-normoglycemic remission and 2) determine whether pioglitazone or sitagliptin therapy will delay an insulin-deficient relapse once insulin is discontinued. The Principal Investigator hypothesizes that measures of beta-cell function at presentation, alone or in combination with measures of insulin sensitivity, will correlate with the ability of a patient to achieve and remain in near-normoglycemic remission. She also hypothesizes that intervention compared to placebo will preserve beta-cell function, improve insulin sensitivity, and prevent an insulin-deficient relapse. This prospective, cohort study with a RCT arm would better characterize the natural history of KPDM, facilitate the direction of long-term therapy, and likely decrease the recurrence of DKA which is associated with increased mortality and morbidity.