Future Research Needs for the Management of Gestational Diabetes: Future Research Needs Document Number 7 (Future Research Needs Paper)

Gestational diabetes mellitus (GDM), the most common medical complication of pregnancy, is defined as carbohydrate intolerance of variable degree, with an onset or first recognition occurring during pregnancy. Studies estimate that GDM affects about 7 percent of births occurring in the United States. GDM is associated with both maternal and neonatal complications. Women with GDM are at high risk for developing noninsulin dependent (type 2) diabetes mellitus. In 2008, the Johns Hopkins University Evidence-based Practice Center (JHU EPC) completed an Agency for Healthcare Research and Quality (AHRQ) funded evidence report on glucose management, delivery management, postpartum risk assessment, and diagnostic tests for type 2 diabetes in women with GDM. The report focused on the following four key questions (KQs): Key Question I. What are the risks and benefits of an oral diabetes agent (e.g., glyburide), as compared to all types of insulin, for GDM? Key Question II. What is the evidence that elective labor induction, cesarean delivery, or timing of induction is associated with benefits or harm to the mother and neonate? Key Question III. What risk factors are associated with the development of type 2 diabetes after a pregnancy with GDM? Key Question IV. What are the performance characteristics of diagnostic tests for type 2 diabetes in women with GDM? The report authors made the following conclusions: (1) maternal glucose levels do not differ substantially in those treated with insulin vs. insulin analogues or oral agents; (2) average infant birth weight may be lower in mothers treated with insulin than with glyburide; (3) induction at 38 weeks may reduce the macrosomia rate, with no increase in cesarean delivery rates; (4) anthropometric measures, fasting blood glucose (FBG), and 2-hour glucose value are the strongest risk factors associated with development of type 2 diabetes; (5) FBG had high specificity, but variable sensitivity, when compared to the 75-gm oral glucose tolerance test (OGTT) in the diagnosis of type 2 diabetes after delivery. Overall, the evidence was graded either as low strength or insufficient to address the key questions. Because of the widespread deficiencies in the literature, the research team identified broad research gaps and suggested higher quality clinical studies to address each key question. Therefore, the framework for identifying and describing research gaps identified in this report may be unique and most applicable to future reports with uniformly low or insufficient strength of evidence. In January 2010, AHRQ requested that the JHU EPC develop and pilot test a process to identify research needs. The objective of the project was to help AHRQ establish a standard process for identifying research needs in its evidence reports and to identify research needs for the management of GDM.