Hemoglobin A1c in predicting progression to diabetes.
ABSTRACT The predictive value of hemoglobin A1c (HbA1c) in comparison to fasting plasma glucose (FPG) is evaluated for 5-year incident diabetes (DM), as HbA1c may be more practical than FPG in the screening for DM in the future. Of 1189 non-DM subjects aged 35-89 years old from the Funagata Study, 57 subjects (4.8%) had developed DM on the WHO criteria at 5-year follow-up. The odds ratio (95% confidence interval: CI) for a one standard deviation increase in FPG/HbA1c was 3.40 (2.44-4.74)/3.49 (2.42-5.02). The area under the receiver operating characteristic curve for FPG/HbA1c was 0.786 (95% CI: 0.719-0.853)/0.785 (0.714-0.855). The HbA1c corresponding to FPG 5.56 mmol/l was HbA1c 5.3%. There was no statistical difference in sensitivity between FPG 5.56 mmol/l and HbA1c 5.3% (61.4% vs. 56.1%), while specificity was higher in HbA1c 5.3% than FPG 5.56 mmol/l (87.8% vs. 82.5%, p-value<0.001). The fraction of incident case from those with baseline IGT was similar between the groups, however the fraction of people above the cut-off was significantly lower in HbA1c 5.3% than FPG 5.56 mmol/l (14.3% vs. 19.6%, p-value<0.001). HbA1c is similar to FPG to evaluate DM risk, and HbA1c could be practical and efficient to select subjects for intervention.
- [show abstract] [hide abstract]
ABSTRACT: The aims of the present study were to observe the natural history of impaired glucose tolerance and to identify predictors for development of non-insulin-dependent diabetes mellitus (NIDDM). A survey of glucose tolerance was conducted in subjects aged 50-74 years, randomly selected from the registry of the middle-sized town of Hoorn in the Netherlands. Based on the mean values of two oral glucose tolerance tests subjects were classified in categories of glucose tolerance according to the World Health Organization criteria. All subjects with impaired glucose tolerance (n = 224) were invited to participate in the present study, in which 70% (n = 158) were subsequently enrolled. During follow-up subjects underwent a repeated paired oral glucose tolerance test. The mean follow-up time was 24 months (range 12-36 months). The cumulative incidence of NIDDM was 28.5% (95% confidence interval 15-42%). Age, sex, and anthropometric and metabolic characteristics at baseline were analysed simultaneously as potential predictors of conversion to NIDDM using multiple logistic regression. The initial 2-h post-load plasma glucose levels and the fasting proinsulin levels were significantly (p < 0.05) related to the incidence of NIDDM. Anthropometric characteristics, the 2-h post-load specific insulin levels and the fasting proinsulin/fasting insulin ratio were not related to the incidence of NIDDM. These results suggest that beta-cell dysfunction rather than insulin resistance plays the most important role in the future development of diabetes in a high-risk Caucasian population.Diabetologia 02/1996; 39(1):113-8. · 6.49 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Short-term variability in measures of glycemia has important implications for the diagnosis of diabetes mellitus and the conduct and interpretation of epidemiologic studies. Our objectives were to characterize the within-person variability in fasting glucose, 2-hour glucose, and hemoglobin A1c (HbA1c) levels and to assess the impact of using repeated measurements for classification of diabetes. We analyzed repeated measurements from 685 fasting participants without diagnosed diabetes from the National Health and Nutrition Examination Survey III Second Examination, a substudy conducted from 1988 to 1994 in which repeated examinations were conducted approximately 2 weeks after the original examination. Two-hour glucose levels had substantially more variability (within-person coefficient of variation [CV(w)], 16.7%; 95% confidence interval [CI], 15.0 to 18.3) compared with either fasting glucose (CV(w), 5.7%; 95% CI, 5.3 to 6.1) or HbA1c (CV(w,) 3.6%; 95% CI, 3.2 to 4.0) levels. The proportion of persons with a fasting glucose level of 126 mg/dL or higher (to convert to millimoles per liter, multiply by 0.0555) on the first test who also had a second glucose level of 126 mg/dL or higher was 70.4% (95% CI, 49.8% to 86.2%). Results were similar using the 2-hour glucose cutoff point of 140 mg/dL or higher. The prevalence of undiagnosed diabetes using a single fasting glucose level of 126 mg/dL or higher was 3.7%. If a second fasting glucose level of 126 mg/dL or higher was used to confirm the diagnosis (American Diabetes Association guidelines), the prevalence decreased to 2.8% (95% CI, 1.5% to 4.0%), a 24.4% decrease. We found high variability in 2-hour glucose levels relative to fasting glucose levels and high variability in both of these relative to HbA1c levels. Our findings suggest that studies that strictly apply guidelines for the diagnosis of diabetes (2 glucose measurements) may arrive at substantially different prevalence estimates compared with studies that use only a single measurement.Archives of Internal Medicine 08/2007; 167(14):1545-51. · 11.46 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Type 2 diabetes mellitus is increasingly common, primarily because of increases in the prevalence of a sedentary lifestyle and obesity. Whether type 2 diabetes can be prevented by interventions that affect the lifestyles of subjects at high risk for the disease is not known. We randomly assigned 522 middle-aged, overweight subjects (172 men and 350 women; mean age, 55 years; mean body-mass index [weight in kilograms divided by the square of the height in meters], 31) with impaired glucose tolerance to either the intervention group or the control group. Each subject in the intervention group received individualized counseling aimed at reducing weight, total intake of fat, and intake of saturated fat and increasing intake of fiber and physical activity. An oral glucose-tolerance test was performed annually; the diagnosis of diabetes was confirmed by a second test. The mean duration of follow-up was 3.2 years. The mean (+/-SD) amount of weight lost between base line and the end of year 1 was 4.2+/-5.1 kg in the intervention group and 0.8+/-3.7 kg in the control group; the net loss by the end of year 2 was 3.5+/-5.5 kg in the intervention group and 0.8+/-4.4 kg in the control group (P<0.001 for both comparisons between the groups). The cumulative incidence of diabetes after four years was 11 percent (95 percent confidence interval, 6 to 15 percent) in the intervention group and 23 percent (95 percent confidence interval, 17 to 29 percent) in the control group. During the trial, the risk of diabetes was reduced by 58 percent (P<0.001) in the intervention group. The reduction in the incidence of diabetes was directly associated with changes in lifestyle. Type 2 diabetes can be prevented by changes in the lifestyles of high-risk subjects.New England Journal of Medicine 06/2001; 344(18):1343-50. · 51.66 Impact Factor