Glucose challenge test screening for prediabetes and undiagnosed diabetes

Division of Endocrinology and Metabolism, Emory University School of Medicine, 101 Woodruff Circle, WMRB Room 1027, Atlanta, GA 30322, USA.
Diabetologia (Impact Factor: 6.67). 06/2009; 52(9):1798-807. DOI: 10.1007/s00125-009-1407-7
Source: PubMed


Diabetes prevention and care are limited by lack of screening. We hypothesised that screening could be done with a strategy similar to that used near-universally for gestational diabetes, i.e. a 50 g oral glucose challenge test (GCT) performed at any time of day, regardless of meal status, with one 1 h sample.
At a first visit, participants had random plasma and capillary glucose measured, followed by the GCT with plasma and capillary glucose (GCTplasma and GCTcap, respectively). At a second visit, participants had HbA(1c) measured and a diagnostic 75 g OGTT.
The 1,573 participants had mean age of 48 years, BMI 30.3 kg/m(2) and 58% were women and 58% were black. Diabetes (defined by WHO) was present in 4.6% and prediabetes (defined as impaired glucose tolerance [2 h glucose 7.8-11.1 (140-199 mg/dl) with fasting glucose <or=6.9 (125 mg/dl)] and/or impaired fasting glucose with plasma glucose 6.1-6.9 mmol/l [110-125 mg/dl]) in 18.7%. The GCTplasma provided areas under the receiver-operating-characteristic curves of 0.90, 0.82 and 0.79 for detection of diabetes, diabetes or prediabetes, and prediabetes, respectively, all of which were higher than GCTcap, random and capillary glucose, and HbA(1c) (p < 0.02 for all). The performance of GCTplasma was unaffected by time after meals or time of day, and was better in blacks than whites, but otherwise comparable in men and women, and in groups with differing prevalence of glucose intolerance. GCTplasma screening would cost approximately US$84 to identify one person with previously unrecognised diabetes or prediabetes.
GCT screening for prediabetes and previously unrecognised diabetes would be accurate, convenient and inexpensive. Widespread use of GCT screening could help improve disease management by permitting early initiation of therapy aimed at preventing or delaying the development of diabetes and its complications.

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    • "A recent study has shown that the patterns of insulin concentration during an OGTT strongly predict the development of diabetes [16]. Thus, the OGTT could provide more accurate information about the risk of diabetes, especially in people with prediabetes who have impaired glucose metabolism [16] [17]. More specifically , plasma insulin and C-peptide concentrations after glucose loading are more likely to reflect b-cell dysfunction and insulin resistance than are fasting samples. "
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    ABSTRACT: Aims The clinical implications of prediabetes for development of type 2 diabetes may differ for Asian ethnicity. We investigated various indices derived from a 2-h oral glucose tolerance test (OGTT) in people with prediabetes to predict their future risk of diabetes. Methods We recruited 406 consecutive subjects with prediabetes from 2005 to 2006 and followed them up every 3–6 months for up to 9 years. Prediabetes was defined as isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), combined glucose intolerance (CGI) or isolated elevated HbA1c (5.7–6.4%, 39–46 mmol/mol) without IFG or IGT. The rate of diabetes conversion was compared between prediabetes categories. The association of glycemic indices with development of diabetes was also investigated. Results Eighty-one patients were diagnosed with diabetes during the 9-year follow-up (median 46.0 months). The rate of diabetes conversion was higher in subjects with CGI (31.9%), or isolated IGT (18.5%) than in those with isolated IFG (15.2%) or isolated elevated HbA1c (10.9%). Surrogate markers reflecting β-cell dysfunction were more closely associated with diabetes conversion than insulin resistance indices. Subjects with a 30-min postload glucose ≥165 mg/dL and a 30-min C-peptide <5 ng/mL had 8.83 times greater risk (95% confidence interval 2.98–26.16) of developing diabetes than other prediabetic subjects. Conclusions In Asians, at least Koreans, β-cell dysfunction seems to be the major determinant for diabetes conversion. A combination of high glucose and low C-peptide levels at 30 min after OGTT may be a good predictor for diabetes conversion in this population
    Full-text · Article · Sep 2014 · Diabetes Research and Clinical Practice
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    • "The study was approved by the Emory University Institutional Review Board and used data from 1,573 adults in the SIGT study, described previously (5). Briefly, this study recruited participants without known diabetes between January 2005 and March 2008. "
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    ABSTRACT: OBJECTIVE Although screening for diabetes and prediabetes is recommended, it is not clear how best or whom to screen. We therefore compared the economics of screening according to baseline risk. RESEARCH DESIGN AND METHODS Five screening tests were performed in 1,573 adults without known diabetes—random plasma/capillary glucose, plasma/capillary glucose 1 h after 50-g oral glucose (any time, without previous fast, plasma glucose 1 h after a 50-g oral glucose challenge [GCTpl]/capillary glucose 1 h after a 50-g oral glucose challenge [GCTcap]), and A1C—and a definitive 75-g oral glucose tolerance test. Costs of screening included the following: costs of testing (screen plus oral glucose tolerance test, if screen is positive); costs for false-negative results; and costs of treatment of true-positive results with metformin, all over the course of 3 years. We compared costs for no screening, screening everyone for diabetes or high-risk prediabetes, and screening those with risk factors based on age, BMI, blood pressure, waist circumference, lipids, or family history of diabetes. RESULTS Compared with no screening, cost-savings would be obtained largely from screening those at higher risk, including those with BMI >35 kg/m2, systolic blood pressure ≥130 mmHg, or age >55 years, with differences of up to −46% of health system costs for screening for diabetes and −21% for screening for dysglycemia110, respectively (all P < 0.01). GCTpl would be the least expensive screening test for most high-risk groups for this population over the course of 3 years. CONCLUSIONS From a health economics perspective, screening for diabetes and high-risk prediabetes should target patients at higher risk, particularly those with BMI >35 kg/m2, systolic blood pressure ≥130 mmHg, or age >55 years, for whom screening can be most cost-saving. GCTpl is generally the least expensive test in high-risk groups and should be considered for routine use as an opportunistic screen in these groups.
    Full-text · Article · Feb 2013 · Diabetes care
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    • "The non-fasting 2-h post 75g glucose concentration strongly predicts adverse outcome for the mother and her offspring (Pettitt et al., 1991). Philips et al also observed that plasma glucose value with a glucose challenge test was unaffected by the time after a meal or time of the day in Normal Glucose Tolerant non pregnant subjects (Philips et al., 2009). Thus, this single test procedure performed irrespective of the last meal timing is rational and a patient friendly approach, which causes least disturbance in her routine activities. "

    Full-text · Chapter · Nov 2011
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