ACOG released updated guidance on gestational diabetes (GDM), which has become increasingly prevalent worldwide. Class A1GDM refers to diet-controlled GDM. Class A2GDM refers to the clinical scenario where medications are required. Highlights and changes from the previous practice bulletin include the following:
ACOG (based on NIH consensus panel findings) supports the ‘2 step’ approach (24 to 28 week 1 hour venous glucose measurement following 50g oral glucose solution), followed by a 100g 3 hour oral glucose tolerance test (OGTT) if positive
Note: Diagnosis of GDM is based on 2 abnormal values on the 3 hour OGTT
ACOG recommends that currently there is insufficient evidence to diagnose GDM based on only one abnormal value
Patients with only one elevated value may require additional surveillance
1 step approach (75 g OGTT) on all women will increase the diagnosis of GDM but sufficient prospective studies demonstrating improved outcomes still lacking
The USPSTF
Recommends screening for gestational diabetes in asymptomatic pregnant persons at ≥24 weeks of gestation or after (B recommendation)
Current evidence is insufficient to assess the balance of benefits and harms of screening for gestational diabetes in asymptomatic pregnant persons <24 weeks of gestation (I statement)
Who Should be Screened Early?
Consider early screening in pregnancy if patient is overweight with BMI of 25 (23 in Asian Americans), and one or more of the following
Physical inactivity
Family history of diabetes – 1st degree relative (parent or sibling)
African American, Native American, Asian American, Latino, or Pacific Islander
Previous pregnancy history of
GDM
Macrosomia (≥ 4000 g)
Hypertension (140/90 mm Hg or being treated for hypertension) | ADA now uses 130/80 cut-off for prediabetes screening
HDL cholesterol ≤ 35 mg/dl (0.90 mmol/L)
Fasting triglyceride ≥ 250 mg/dL (2.82 mmol/L)
PCOS
Conditions associated with insulin resistance (e.g., acanthosis nigricans, morbid obesity)
Hgb A1C ≥ 5.7%, impaired glucose tolerance or impaired fasting glucose | If A1C>6.5%, diagnosis of pregestational diabetes is met and GCT/GTT not needed
Prediabetes and Diabetes Type 2: Screening and Making the Diagnosis
Clinical Actions:
Diabetes results when the pancreas cannot respond to or produce insulin, leading to abnormal metabolism of carbohydrates and elevated levels of glucose in the blood and urine. Type 2 diabetes (previously “noninsulin-dependent diabetes” or “adult-onset diabetes”) accounts for 90–95% of all diabetes. Type 2 diabetes is caused by a progressive loss of β-cell insulin secretion, usually associated with insulin resistance. Prediabetes is diagnosed when glucose levels start to rise due to β-cell insulin secretion failure, but diagnostic criteria are not yet met for Type 2 diabetes.
Other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans)
People with HIV
Screen for diabetes and prediabetes with a fasting glucose test
Before starting antiretroviral therapy
At the time of switching antiretroviral therapy
3 to 6 months after starting or switching antiretroviral therapy
If initial screening results are normal, fasting glucose should be checked annually
Patients with prediabetes (A1C ≥5.7% [39 mmol/mol], IGT, or IFG) should be tested yearly
Women who were diagnosed with GDM should have lifelong testing at least every 3 years
For all other patients, testing should begin at age 35 years
If results are normal, testing should be repeated at a minimum of 3-year intervals, with consideration of more frequent testing depending on initial results and risk status
AACE/ACE
Begin at age 45 without risk factors
Screening based on risk factors: In addition to the above list, AACE/ACE includes the following factors
Antipsychotic therapy for schizophrenia and/or severe bipolar disease
Chronic glucocorticoid exposure
Sleep disorders (e.g., obstructive sleep apnea, chronic sleep deprivation, and night shift occupation) with glucose intolerance
Normal glucose values: Every 3 years
Consider annual screening for patients with 2 or more risk factors
USPSTF
Screen for prediabetes and type 2 diabetes in adults aged 35 to 70 years who have overweight (BMI ≥25) or obesity (BMI ≥30)
Clinicians should offer or refer patients with prediabetes to effective preventive interventions
Above are Grade B recommendations: Offer or provide this service
Diagnostic Criteria
Normal
Fasting plasma glucose (FPG) <100 mg/dL (5.6 mmol per L)
Oral glucose tolerance test (OGTT) with 75g glucose load
2h (plasma glucose) PG <140 mg/dL (7.8 mmol per L)
High Risk for Diabetes (prediabetes)
Impaired fasting glucose (IFG): FPG ≥100 to 125 mg/dL (5.6 to 6.9 mmol per L)
Impaired glucose tolerance (IGT): 2h PG ≥140 to 199 mg/dL (7.8 to 11.0 mmol per L)
A1C 5.7% to 6.4%
Note: Patients with prediabetes should be tested yearly
Diabetes: Glucose criteria are preferred for the diagnosis of DM
FPG ≥126 (7.0 mmol per L) mg/dL
OGTT: 2h PG ≥200 mg/dL (11.1 mmol per L)
Random PG ≥200 mg/dL (11.1 mmol per L) with the following symptoms of hyperglycemia
Note: Always confirm diabetes diagnosis with repeat glucose or A1C testing on another day
SYNOPSIS:
Prediabetes is not a clinical disorder but rather an important risk factor for diabetes and cardiovascular disease. While there are some differences between organizations regarding risk factors for screening and diagnostic cut-offs, all agree as to the importance of identifying those at risk for significant cardiovascular events if diabetes is left untreated. The prognosis for type 2 diabetes varies and is very dependent on glucose control.
KEY POINTS:
Symptoms of
Diabetes (related to hyperglycemia)
Excessive urination, thirst and hunger
Unexpected weight loss
Increased susceptibility to infections, especially yeast or fungal infections
Weak, tired feeling
Dry mouth
Blurry vision
Deposits of blood, or puffy yellow spots in the retina
Update from the ACP: New Hemoglobin A1c Targets for Type 2 Diabetes Mellitus
SUMMARY:
The ACP has updated guidance to help providers better target hemoglobin A1c (HbA1c) targets for the pharmacologic treatment of type 2 diabetes. The ACP recommends
Clinicians should personalize goals for glycemic control in patients with type 2 diabetes on the basis of a discussion of benefits and harms of pharmacotherapy, patients’ preferences, patients’ general health and life expectancy, treatment burden, and costs of care.
Clinicians should aim to achieve an HbA1c level between 7% and 8% in most patients with type 2 diabetes.
Clinicians should consider deintensifying pharmacologic therapy in patients with type 2 diabetes who achieve HbA1c levels less than 6.5%.
Clinicians should treat patients with type 2 diabetes to minimize symptoms related to hyperglycemia and avoid targeting an HbA1c level in patients with a life expectancy less than 10 years due to advanced age (80 years or older), residence in a nursing home, or chronic conditions (such as dementia, cancer, end-stage kidney disease, or severe chronic obstructive pulmonary disease or congestive heart failure) because the harms outweigh the benefits in this population.
KEY POINTS:
Other guidelines reviewed in this document include
The ADA guidelines set the following targets
<7% for the general population
Consider less stringent goals (<8%) for patients with limited life expectancy or significant comorbidities
Consider more stringent goals (<6.5%) for selected patients without significant hypoglycemia
Short duration of diabetes
Type 2 diabetes treated with lifestyle or metformin only
Long life expectancy
No CVD
Note: The ADA has issued a statement that it is “deeply concerned by the new guidance” and “that a reasonable A1c goal for many nonpregnant adults with type 2 diabetes is less than 7 percent based on the available evidence to date from the ACCORD, ADVANCE, VADT and UKPDS international clinical trials, which were evaluated and incorporated into ADA’s Standards of Care.” (see ‘Learn More – Primary Sources’ below)
Scottish Intercollegiate Guidelines Network (SIGN) guideline is similar to ADA
AACE/ACE
≤6.5% if target can be achieved safely
NICE
6.5% for patients managed with
Lifestyle and diet
Lifestyle and diet with single drug and no hypoglycemia
7% for patients on medications associated with hypoglycemia
Institute for Clinical Systems Improvement
< 7% to < 8% based on patient factors
VA/DoD
6% to 7% for patients with a life expectancy > 10 to 15 years and no or mild microvascular complications
7% to 8.5% for those with established microvascular or macrovascular disease, comorbid conditions, or a life expectancy of 5 to 10 years
8% to 9% for those with a life expectancy <5 years, significant comorbid conditions, advanced complications of diabetes, or difficulties in self-management attributable to mental status, disability, or other factors (12)
Review of Literature
Overall, the ACP did not find that the benefits of lower HbA1c targets justified potential risks
ACP reviewed 5 large RCTs comparing intensive (achieved HbA1c levels, 6.3% to 7.4%) versus less intensive (achieved HbA1c levels, 7.3% to 8.4%) treatment targets
Main effect: More intensive glycemic control resulted in small absolute reductions in risk for microvascular surrogate events (e.g., retinopathy on ophthalmologic screening) but not clinical events such as loss of vision
One trial of metformin in overweight adults showed a reduction in all-cause and diabetes-related death through at least 10 years
In all studies, more intensive therapy required higher dose medications and was associated with more adverse events (including increased risk of death in 1 study)
NOTE: All guidelines allow for higher HbA1c targets depending on comorbid conditions and limited life expectancy
ACOG and SMFM Both Release Guidance on Gestational Diabetes – Insulin vs Metformin for First-Line Therapy?
SUMMARY:
The SMFM released a statement on the use of metformin as a first-line alternative to insulin in women with GDM. ACOG has also released an update to the major 2017 Practice Bulletin which also addresses this issue and still considers insulin the preferred option to treat women who are not adequately controlled with appropriate nutritional therapy.
Both the ACOG update and SMFM statement summarize the literature, including recent meta-analyses on the comparison studies between insulin and metformin
Data has been conflicting based on whether non-published studies included women with type II diabetes
Some studies have demonstrated a higher risk for preterm birth (but lower for gestational hypertension) in the metformin group while other studies have not identified a difference in preterm birth
ACOG
Based on current evidence, ACOG states that, consistent with ADA guidance, insulin is the ‘preferred’ approach for GDM for women not sufficiently controlled with diet and exercise
In addition, the ACOG update states
Thus, although metformin may be a reasonable alternative approach to treat gestational diabetes, it is important to counsel women about the lack of superiority when compared with insulin, the placental transfer of the drug, and the absence of long-term data in exposed offspring. Additionally, in the aforementioned prospective trials, between 26% and 46% of women who took metformin alone eventually required insulin.
SMFM
Upon review of the evidence, SMFM considers metformin to be a “reasonable and safe first-line pharmacologic alternative to insulin”
More data is needed to establish long-term safety of oral agents
Glyburide has been associated with adverse neonatal events, such as macrosomia and hypoglycemia but SMFM also acknowledges that “the evidence of benefit of one oral agent over the other remains limited”
SMFM does acknowledge that their statement conflicts with ACOG, however
…this difference is based on the values placed by different experts and providers on the evidence available in the medical literature and is not meant to represent an exclusive course of management.
KEY POINTS:
Other ACOG Updates
One abnormal values on the 3 hour OGTT
In the previous 2017 practice bulletin, while it was clearly stated that diagnosis of GDM is based on 2 abnormal values on the 3 hour OGTT, ACOG seemed to suggest that one abnormal value may be sufficient to make the diagnosis
In the updated 2018 version, ACOG has clarified that statement
One abnormal glucose level may warrant a higher level of scrutiny, but is not sufficient for diagnosis
More studies are required to determine risk of adverse outcomes and who would benefit from making this a diagnostic criteria
Clarification of insulin use and dosage
ACOG has clarified the previous practice bulletin and now states that in women who have abnormal postprandial and fasting glucose levels
Insulin starting dose is 0.7-1.0 units/kg daily
Dosage should be divided and long-acting or intermediate-acting insulin in combination with short-acting insulin should be used
Previously, the 2017 documented stated that insulin was ‘first line’ therapy and the updated document now says ‘preferred’
ACOG recognizes that clinicians may assess the clinical circumstances and find the use of oral agents to be a better alternative in women (e.g., patient cannot afford insulin or feel administering the drug would be unsafe)
Macrosomia and cesarean section
The recommendation that women with GDM should be counseled about the risks/benefits of a scheduled cesarean section if the estimated fetal weight is ≥4,500 g has been moved from ‘limited or inconsistent scientific evidence’ (Level B) to ‘consensus and expert opinion’ (Level C)
CONCEPTT Study: Time for Continuous Glucose Monitoring for All Pregnant Women with Type 1 Diabetes?
BACKGROUND AND PURPOSE:
Continuous glucose monitoring (CGM) provides contemporaneous glucose readings, thus allowing patients to adjust insulin in real-time
Data in non-pregnant women show benefit but conflicting data in pregnancy
Feig et al. (Lancet, 2017) determined the effectiveness of continuous glucose monitoring (CGM) on maternal glucose control compared to capillary glucose monitoring alone
31 hospital centers in Canada, England, Scotland, Spain, Italy, Ireland, and the USA
Women aged 18 to 40 years, with type 1 diabetes for a minimum of 1 year, receiving intensive insulin therapy, and pregnant or planning pregnancy
Live singleton fetus confirmed by ultrasound
≤13 weeks and 6 days’ gestation
Pregnant: HbA1c between 6.5–10.0% (48–86 mmol/mol)
Planning for pregnancy: 7.0–10.0% (53–86 mmol/mol)
Ran 2 trials in parallel for (1) pregnant and (2) planning pregnancy
In both trials, participants were assigned to the following cohorts
Receive CGM in addition to capillary glucose monitoring
Receive capillary glucose monitoring
Randomization was stratified by insulin delivery and baseline HbA1c
Primary outcome was change in HbA1c
at 34 weeks’ gestation in pregnant participants
at 24 weeks for planning pregnancy participants
Secondary outcomes included obstetric and neonatal health outcomes
RESULTS:
325 women were randomized
When comparing pregnant CGM users to capillary monitored group, CGM users
had a slightly greater change in HbA1c (mean difference -0.19%; 95% CI -0.34 to -0.03; p=0.0207)
Spent more time in target range (68% vs 61%; 0.0034)
Spent less time hyperglycemic range (27% vs 32%; p= 0.0279)
Had comparable hypoglycemic episodes
Spent comparable amount of time in hypoglycemic range (3% vs 4%, respectively)
Neonatal outcomes in CGM users were significantly improved
Lower incidence of large for gestational age (odds ratio [OR] 0.51, 95% CI 0.28 – 0.90; p=0.0210)
Fewer NICU admissions lasting more than 24 h (OR 0.48; 95% CI 0.26 – 0.86; p=0.0157)
Fewer incidences of neonatal hypoglycemia (OR 0.45; 95% CI 0.22 to 0.89; p=0.0250)
1-day shorter length of hospital stay (p=0.0091)
There was no apparent benefit of CGM for women planning pregnancy
CGM users had significantly more adverse skin reactions during trials (48% CGM vs 8% control during pregnancy; 44% CGM vs 9% control planning pregnancy)
Data was generalizable across centers
CONCLUSION:
CGM during pregnancy in patients with type 1 diabetes is linked to improved neonatal outcomes, likely because of better maternal glycemic control and reduced maternal hyperglycemia
Number needed to treat (NNT) with CGM
6 pregnant women NNT to prevent one NICU admission
6 pregnant women NNT to prevent one large for gestational age
8 pregnant women NNT to prevent one case of neonatal hypoglycemia
The authors conclude that guidelines in type 1 diabetes in pregnancy should be revised to recommend offering CGM to pregnant women with type 1 diabetes using intensive insulin therapy in the first trimester
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