An independent panel convened this week by the National Institutes of Health has concluded that despite potential advantages of adopting a new diagnostic approach for gestational diabetes mellitus (GDM), more evidence is needed to ensure that the benefits outweigh the harms. The panel recommended following the current diagnostic approach until further studies are conducted.
“The panel believes that cost-benefit, cost-effectiveness, and cost-utility research is needed to more fully understand the implications of changing diagnostic protocols for GDM,” said Dr. Peter VanDorsten, conference panel chairperson and Lawrence L. Hester, Jr. Professor, Medical University of South Carolina, Charleston.
GDM is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy. GDM is currently estimated to occur in 5-6 percent of U.S. pregnancies, affecting more than 240,000 births annually. GDM is associated with an increased risk of complications for both the mother and child, including maternal high blood pressure, cesarean delivery, and neonatal low blood sugar. In addition, up to half of women who have experienced GDM will develop type 2 diabetes later in life.
Different approaches are used to identify GDM, and the number of women diagnosed varies with the test criteria used. Tests differ based on whether there is a need for fasting, the grams of glucose given, the number of appointments, and the glucose threshold for diagnosis. Most health providers in the U. S. use a two-step approach that involves a nonfasting glucose screening of all pregnant women, followed by a glucose tolerance test for a subset. However, many other countries and prominent organizations, such as the American Diabetes Association, now support a one-step approach for all pregnant women. There is much debate regarding choice of tests and the trade-offs of each approach.
The panel identified certain operational advantages to the one-step approach, including a consistent diagnostic standard across the lifespan and better comparability of research outcomes globally. From a clinical perspective, the one-step approach could promote better standardization of patient care and allow a diagnosis to be achieved within the context of one visit as opposed to two.
However, despite potential benefits, there are several concerns about the one-step process. This approach is anticipated to increase the frequency of the diagnosis by two- to threefold, to a prevalence of approximately 15–20 percent. It is not known whether the additional women identified and their children will benefit from treatment. There is evidence that the labeling of these women may have unintended consequences, such as an increase in anxiety, clinic visits, cesarean delivery, and more intensive antenatal and newborn assessments. Moreover, the additional visits and testing to care for these women would impact their lives and would generate additional healthcare costs.
“The panel believes that there is not presently sufficient evidence to adopt a one-step approach. We are particularly concerned that the adoption of new criteria would increase the prevalence and the corresponding costs of GDM, without clear demonstration of improvements in key short- and long-term outcomes,” said Dr. VanDorsten. “However, given the potential benefits of a one-step approach, resolution of these concerns would change our conclusion.”
The panel suggested that additional research be conducted to resolve key research gaps. An initial step would be to assess cohorts that are using the single test approach to determine if more stringent diagnostic criteria would identify a population similar in prevalence and risk to that currently identified by the two-step approach now in use in the U. S. Subsequent research that focuses on women with less severe disease could help to determine if they would similarly benefit from this diagnostic approach.
Health services research should be performed to see if less expensive but equally or more effective approaches can be found for the management of GDM. The panel further recommended that prospective cohort studies of the real-world impact of GDM treatment on care utilization be conducted. It also supported additional research to understand patient preferences and the psychological consequences of a diagnosis, given that different approaches represent different burdens for patients.
The panel stated that studies should be conducted on interventions during pregnancy that can lead to long-term improvements in the health of women, children, and families. Healthy lifestyle interventions for women diagnosed with GDM, such as physical activity and medical nutrition therapy, may be of value.
“Pregnancy is the window into the future health of women, and the opportunity to make healthy changes during that critical time should not be missed,” said Dr. VanDorsten.
An updated version of the panel’s draft statement, which incorporates public comments received during the conference, will be posted later today at https://consensus.nih.gov/2013/gdm.htm.
A press telebriefing will be held to discuss the panel’s findings today at 2 p.m. EST. To participate, call 1–888–428–7458 (inside the United States) or 201–604–5177 (international) and reference the NIH Consensus Development Conference. Audio playback will be available shortly after conclusion of the telebriefing and can be accessed by calling 1–888–632–8973 (United States) or 201–499–0429 (international) and entering replay code 38277108.
The Consensus Development Conference was sponsored by the NIH Office of Disease Prevention and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, along with other NIH and U.S. Department of Health and Human Services components. This conference was conducted under the NIH Consensus Development Program, which convenes conferences to assess the available scientific evidence and develop objective statements on controversial medical issues.
The 15-member consensus development panel included a patient representative as well as experts in the fields of maternal-fetal medicine, obstetrics and gynecology, endocrinology and infertility, pediatrics, nutrition, epidemiology, economics, and statistics. A complete listing of the panel members and their institutional affiliations is included in the draft conference statement. Additional materials, including panel biographies, photos, and other related resources, are available at https://consensus.nih.gov/2013/gdmresources.htm. Interviews with panel members can be arranged by contacting Deborah Langer at 301–443–4569 or firstname.lastname@example.org.
The conference was webcast live and will be archived shortly. Links to the archived webcast will be available at https://consensus.nih.gov/2013/gdm.htm.
In addition to the material presented at the conference by speakers and the comments of conference participants presented during discussion periods, the panel considered pertinent research from the published literature and the results of a systematic review of the literature. The systematic review was prepared through the Agency for Healthcare Research and Quality Evidence-based Practice Centers (EPC) program by the University of Alberta Evidence-based Practice Centre. The EPCs develop evidence reports and technology assessments based on rigorous, comprehensive syntheses and analyses of the scientific literature, emphasizing explicit and detailed documentation of methods, rationale, and assumptions. A link to the evidence report, Screening and Diagnosing Gestational Diabetes Mellitus, is available at https://consensus.nih.gov/2013/docs/EvidenceReport.pdf (2.86 MB).
The panel’s statement is an independent report and is not a policy statement of the NIH or the Federal Government. The NIH Consensus Development Program was established in 1977 as a mechanism to judge controversial topics in medicine and public health in an unbiased, impartial manner. The NIH has conducted 159 conferences, addressing a wide range of issues. A backgrounder on the NIH Consensus Development Program process is available at https://consensus.nih.gov/.
The Office of the Director, the central office at the NIH, is responsible for setting policy for the NIH, which includes 27 Institutes and Centers. This involves planning, managing, and coordinating the programs and activities of all NIH components. The Office of the Director also includes program offices that are responsible for stimulating specific areas of research throughout the NIH. Additional information is available at http://www.nih.gov/icd/od.
About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): The NICHD sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit the Institute’s website at http://www.nichd.nih.gov/.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.