Gestational Impaired Glucose Tolerance Linked to Postpartum Metabolic Dysfunction Outcomes

News Author: Laurie Barclay, MD
CME Author: Charles Vega, MD

 

 

July 24, 2008 台州市中心医院中西医结合科张茂华

— Pregnant women with gestational impaired glucose tolerance (GIGT) may exhibit the same adverse outcomes as do women with gestational diabetes mellitus, according to the results of a study reported in the July issue of Diabetes Care.

"GIGT, defined by a single abnormal value on antepartum 3-h oral glucose tolerance test (OGTT), is a metabolically heterogeneous disorder," write Ravi Retnakaran, MD, from the Leadership Sinai Centre for Diabetes, Mount Sinai Hospital in Toronto, Canada, and colleagues. "Indeed, the antepartum metabolic phenotype of women with a single abnormal value at 1 h during the OGTT (1-h GIGT) resembles that of women with gestational diabetes mellitus (GDM), whereas GIGT at 2 or 3 h (2/3-h GIGT) is similar to normal glucose tolerance (NGT). Thus, we hypothesized that 1-h GIGT would be associated with the same adverse outcomes as GDM, i.e., increased infant birth weight and postpartum metabolic dysfunction."

In this study, 361 women underwent an antepartum glucose challenge test (GCT) and a 3-hour OGTT. Obstetric [ɒb"stetrik] 形容词  产科(学)的，助产的outcome was evaluated at delivery分娩, and OGTT was performed at 3 months postpartum. On the basis of antepartum GCT/OGTT, participants were categorized ["kætəgə,raiz] 把…分门别类，把…分类into 5 study groups: gestational diabetes mellitus (n = 97), 1-hour GIGT (n = 28), 2/3-hour GIGT (n = 34), abnormal GCT NGT (abnormal GCT result with NGT on OGTT; n = 128), and normal GCT NGT (normal GCT result with NGT on OGTT; n = 74). Glycemia was defined as an area under the glucose curve, and β-cell function was measured with an insulinogenic index/homeostasis [,həuməu"steisis] model determination of insulin resistance.

Although the rate of cesarean delivery was higher in women with 1-hour GIGT, birth weight was not significantly different between the groups without gestational diabetes mellitus (P = .1978). Glycemia at 3 months postpartum progressively increased across the groups from normal GCT NGT to abnormal GCT NGT results to 2/3-hour GIGT to 1-hour GIGT to gestational diabetes mellitus (P < .0001), whereas insulin sensitivity (P = .002) and β-cell function progressively decreased (P < .0001). The strongest independent negative predictors of insulinogenic index/homeostasis model determination of insulin resistance were gestational diabetes mellitus (t = –4.1; P < .0001) and 1-hour GIGT (t = –3.8; P = .0002).

A limitation of this study is the relatively small sample of women with GIGT.

"Like GDM, 1-h GIGT is associated with postpartum glycemia, insulin resistance, and β-cell dysfunction," the study authors write. "Furthermore, its independent association with β-cell dysfunction, in particular, suggests that 1-h GIGT, like GDM, may predict an increased future risk of type 2 diabetes and hence may identify a high-risk patient population that warrants postpartum surveillance."

The Canadian Institutes of Health Research supported this study. Dr. Retnakaran is supported by a Canadian Diabetes Association Clinician-Scientist. One of the coauthors holds a Tier II Canada Research Chair in Diabetes Epidemiology and is supported through a Canadian Diabetes Association Scholarship. Another coauthor holds the Sam and Judy Pencer Family Chair in Diabetes Research at Mount Sinai Hospital and the University of Toronto.

The costs of publication of this article were defrayed in part by the payment of page charges, mandating that it must therefore be marked "advertisement" solely to indicate this fact.

Diabetes Care. 2008;31:1275-1281.