For info and comment.
American Diabetes Association Consensus Statement
on IFG and IGT
Source:
http://www.ndei.org/v2/Files/Clinical_Insights_April_2007_Final.pdf
CLINICAL INSIGHTS ® IN Diabetes
Professional Postgraduate Services ®
VOLUME 10, NUMBER 4 o APRIL 2007
"MAYER B . DAVIDSON, MD,* CO-EDITOR-IN-CHIEF; SAUL GENUTH,
MD,† REVIEWER;
TERRENCE F. FAGAN,‡ MANAGING EDITOR; MARK A. PALANGIO,§
WRITER
American Diabetes Association Consensus Statement
on IFG and IGT
Prediabetes is characterized by impaired fasting glucose
(IFG) and/or impaired glucose tolerance (IGT). Most
individuals with IFG or IGT will develop progressive
hyperglycemia, eventually meeting the criteria for type 2
diabetes.
To address the clinical implications of the prediabetes
states of IFG and IGT, the American Diabetes Association
(ADA) convened a consensus conference on October 16-18,
2006, consisting of a 7-member panel of experts in diabetes,
endocrinology, and metabolism. The following information was
discussed at that meeting.
IFG is defined by an elevated fasting plasma glucose (FPG)
concentration (=100 and <126 mg/dL). IGT is defined by an
elevated 2-hour plasma glucose concentration (=140 and <200
mg/dL) after a 75-g glucose load on the oral glucose
tolerance test (OGTT) in the presence of an FPG
concentration <126 mg/dL.
The prevalence of IFG and IGT in the United States has been
estimated to be approximately 26% and 15%, respectively.
Both are expected to continue to increase in the future. The
natural history of patients with IFG/IGT varies, with
approximately 25% progressing to diabetes, 50% remaining in
their abnormal glycemic state, and 25% reverting to normal
glucose tolerance (NGT) over a period of 3 to 5 years.
Furthermore, IFG and IGT have different rates of progression
to diabetes.
Longitudinal studies have revealed that both IFG and IGT are
associated with a modest increase in the hazard ratio
(approximately 1.1-1.4) for cardiovascular disease (CVD),
with IGT being a slightly stronger risk predictor. It is
unclear if the CVD risk is related to the presence of IFG or
IGT per se or the subsequent development of diabetes.
IFG and IGT have different pathophysiologic mechanisms, as
suggested by dissimilar oral glucose tolerance curves. Both
isolated IFG and isolated IGT are insulin-resistant states,
but these states differ in their site of insulin resistance.
Individuals with isolated IFG mainly have hepatic insulin
resistance and normal muscle insulin sensitivity, whereas
individuals with isolated IGT have normal to slightly
reduced hepatic insulin sensitivity and moderate to severe
muscle insulin resistance. Individuals with both IFG and IGT
manifest both muscle and hepatic insulin resistance.
Moreover, the pattern of insulin secretion varies between
IFG and IGT. Individuals with isolated IFG display a
decrease in first-phase (0-10 min) insulin secretory
response to intravenous glucose as well as a reduced
early-phase (first 30 min) insulin response during the OGTT.
Yet, in isolated IFG, the late-phase (60-120 min) plasma
insulin response with OGTT is normal.
Isolated IGT also has a deficiency in early-phase insulin
secretion with OGTT, along with a severe deficit in
late-phase insulin secretion.
Intensive lifestyle interventions can delay the onset of
diabetes and modestly reduce CVD risk factors. It remains to
be seen if these changes will lead to meaningful reductions
in CVD events. Furthermore, it is unclear if the use of
pharmacologic agents to prevent or delay diabetes will
reduce CVD risk or events. Despite the lack of direct data
supporting the long-term benefits of diabetes prevention,
the ADA Panel believes in the concept of early intervention
based on the potential for delaying the onset of diabetes,
preserving ß-cell function, and delaying or preventing
microvascular and cardiovascular complications.
For patients with IFG or IGT, the Panel recommends lifestyle
modification including 5% to 10% weight loss and moderate
intensity physical activity approximately 30 min/day. The
Panel recommends lifestyle modification and metformin (850
mg twice per day) for individuals with IFG and IGT and any
of the following:
<60 years of age, BMI =35 kg/m2, family history of diabetes
in first-degree relatives, elevated triglycerides, reduced
high-density lipoprotein cholesterol, hypertension, or A1C
>6.0%.
If metformin is to be used, both IFG and IGT must be
documented. At this time, the Panel recommends that only
metformin be considered as drug therapy for combined IFG and
IGT based on effectiveness, safety, tolerability, and cost.
Screening for IFG/IGT is identical to screening for
diabetes. Because IFG/IGT and diabetes have the same risk
factors, screening for IFG/IGT and diabetes should occur in
the same patient population. Currently, FPG and 2-hour OGTT
are the recommended tests for detecting all states of
hyperglycemia. According to the Panel, the most efficient
testing sequence is an FPG (the preferred test to detect
diabetes) followed by the 2-hour OGTT on a subsequent day to
identify combined IFG/IGT. The Panel also recommends that
routine monitoring should be performed with A1C testing
semi-annually in individuals with IFG/IGT being treated with
metformin.
Those who are not receiving drug therapy should be seen
annually.
Nathan DM et al. Impaired fasting glucose and impaired
glucose tolerance: implications for care. Diabetes Care.
2007;30:753-759.
COMMENTARY
SAUL GENUTH, Professor of Medicine, Case Western Reserve
University School of Medicine.
Cleveland, Ohio.
The ADA consensus panel on impaired glucose tolerance (IGT)
and impaired fasting glucose (IFG) has moved this important
clinical and public health area forward by providing clear
and sound recommendations for screening and treatment. These
are based on a concise review of updated epidemiological,
pathophysiological and clinical trial considerations. The
high prevalence of IGT and IFG individually and combined are
a major public health problem, even though only (!) 25% of
these patients go on to develop diabetes and 25% revert to
normal over the ensuing 3-5 years; 70%, however, may develop
diabetes over their lifetimes.
People with isolated IGT or IFG should be treated with a
lifestyle regimen that leads to 5% to 10% weight loss and
maintains 30 minutes per day of moderate activity such as
walking. A 58% reduction in conversion to diabetes over 3
years can be expected. Individuals who have both IFG and IGT
and any of the following: <60 years of age, BMI = 35, family
history of diabetes in first-degree relatives, elevated
triglycerides, reduced HDL cholesterol, or A1C >6.0%
should have metformin 850 mg twice daily added for
prevention.
Screening for IFG or IGT (and simultaneously for diabetes
itself) of candidates identified by ADA standards of care is
recommended sequentially by FPG on day 1 followed by OGTT on
a subsequent day. In this writer’s view, for very high-risk
candidates (eg, family history of diabetes in both parents
and/or multiple siblings), it may be more efficient to
simply perform an OGTT, which automatically includes FPG."
Cheers, Alan, T2, Australia.
d&e, metformin 1500mg, ezetrol 10mg
Everything in Moderation – Except Laughter.
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