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To compare recent U.S. and U.K. guidelines on gestational diabetes mellitus (GDM).
The guidelines from the American Diabetes Association, the American College of Obstetricians and Gynecologists, and the National Institute for Health and Clinical Excellence (NICE) in the U.K. were collated and compared using a general inductive approach.
There are substantial differences in the recommendations between the U.K. and the U.S. guidelines. Of particular note are the reduced sensitivities of the early and later antenatal and postnatal screening and diagnostic criteria. NICE undertook a cost-effectiveness analysis using lower prevalence estimates and limited outcomes and still showed screening for GDM to be cost-effective.
The latest NICE recommendations appear to reduce access to proven, cost-effective management of GDM, an issue relevant in the current U.S. health care policy debate.
In an age of increasing patient empowerment, the diagnosis of gestational diabetes mellitus (GDM) provides a woman with the knowledge that her baby has an increased chance of complications before, during, and after birth (including an increased chance of obesity and/or diabetes in the future); that she herself has an increased chance of future diabetes; and that future pregnancies are more likely to be complicated by diabetes (gestational or otherwise) (1). Such knowledge could be harmful if there were no opportunities to reduce these risks. However, there is now good evidence that there are fewer obstetric and neonatal complications with intensive management (2) and that future diabetes cases can be delayed and possibly avoided (3). There is even evidence that there may be fewer incidents of postnatal depression following the diagnosis and management of GDM than among untreated women (2). To further the recent debate on the screening and detection of GDM (4,5), we have compared the different approaches to the detection and management of GDM recommended by the American Diabetes Association (ADA) (6), the American College of Obstetricians and Gynecologists (ACOG) (7), and the National Institute for Health and Clinical Excellence (NICE) in the U.K. (8).
NICE is wholly funded by the U.K. government to provide “national guidance on promoting good health and preventing and treating ill health.” NICE assessments are multidisciplinary and include both research and health economic considerations, the latter giving a National Health Service, rather than a societal, perspective. NICE clinical guidelines for diabetes in pregnancy (8) were initially published in March 2008 and revised in July 2008, and a brief critique was published in September 2008 (9).
The guidelines from the three organizations were collated and compared using a general inductive approach. Each guideline category has been treated as a “theme.”
Unlike NICE, the ADA and ACOG guidelines do not include a cost-effectiveness component. NICE used a single cost-effectiveness model addressing screening, diagnosis, and treatment, and the model was used to direct the guideline recommendations. Using the data from the Australian Carbohydrate Intolerance Study in Pregnant Women (ACHOIS) (2), NICE demonstrated that the screening, diagnosis, and treatment of GDM are cost-effective.
This comparison of NICE, ADA, and ACOG guidelines has identified a number of key areas where the recommendations are markedly divergent. Of particular importance are:
The recent point-counterpoint (4,5) comprehensively debated is in regards to whether screening for GDM should be selective (i.e., using risk factors) or universal (i.e., using blood tests). There was general agreement on the risk factors of importance, while the latter addressed the broader issues of complexity and long-term benefits. NICE recommendations exclude several risk factors, including some shown to be cost-effective. NICE cost-effectiveness analysis substantially understated the benefits of screening because the basic decision tree structure omitted many avoidable downstream costs including some maternal morbidity (e.g., preeclampsia), neonatal morbidity (e.g., hypoglycemia), long-term maternal morbidity (e.g., preventable complications by earlier diabetes diagnosis and intervention), and long-term offspring risk (e.g., fetal morbidity if undiagnosed diabetes in a subsequent pregnancy; possibly future obesity and diabetes) (10).
NICE cost-effectiveness analysis acknowledged that a large number of assumptions were made “owing to data limitations and methodological complexity” and that there was potential for underestimating the true costs and effects (by using a cohort excluding those with worse glucose control) (2). The published modeling showed that universal screening becomes more cost-effective as the disease prevalence increases and used a sensitivity analysis with prevalence estimates of GDM ranging from 2–5%; actual GDM prevalence is now running at least 5–8% (1).
Women with undiagnosed type 2 diabetes are significantly more prone to have babies with malformations and may have established diabetic complications (e.g., nephropathy and retinopathy) requiring close follow-up to ensure prompt restoration of normoglycemia. NICE recommendations delay the time to testing and ignore important criteria (e.g., strong family history). Given the often asymptomatic nature of type 2 diabetes and its potential to cause severe pregnancy complications, we consider that testing should be undertaken early in those at high risk, ideally as part of the first antenatal contact.
NICE dependence on fasting plasma glucose screening without performing an oral glucose tolerance test (OGTT) has been shown to reduce the sensitivity of identifying postpartum diabetes and impaired glucose tolerance (IGT) by 38–60% (11–12). In another study, 83% of those with IGT and 56% of those with diabetes would have been missed (13). The follow-up of women with a history of GDM is becoming increasingly important because of their increased risk of progression to type 2 diabetes (1) and the secular trend for a shortening of time between GDM and the development of diabetes (14). Many of these women would have been diagnosed at OGTT on the 2-h glucose alone, avoiding the risk of undiagnosed diabetes at the next pregnancy (should one occur). Moreover, without an OGTT, IGT cannot be identified. This is particularly important given the clear evidence that progression to subsequent diabetes can be reduced by over 50% (3).
Among increasingly empowered, knowledgeable, and “Internet savvy” patients, clinicians run the risk of having their management undermined by conflicting guidelines, making the implementation of clinical care substantially harder and more time-consuming. NICE guidelines are a relatively new addition to the scene but appear to be the most minimalist in relation to screening and postnatal follow-up (1). Fortunately, the completion of the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study (15) now provides a large observational cohort that is being used to redefine diagnostic criteria for GDM in relation to adverse outcomes.
In conclusion, the comparison between NICE, ADA, and ACOG guidelines has demonstrated significant differences in recommendations for the screening, diagnosis, and management of GDM. Cost-effective management is a major issue in the debate on health care reform in the U.S., and current NICE recommendations appear to reduce access to proven, cost-effective GDM management.
No potential conflicts of interest relevant to this article were reported.
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