Sensory function and albumin excretion according to diagnostic criteria for diabetes

OBJECTIVE: The purpose of this study was to examine sensory function and albumin excretion according to categories of glucose tolerance in individuals undergoing screening for diabetes. RESEARCH DESIGN AND METHODS: Sensory function and albumin excretion measurements were obtained in 636 individuals at the time of screening for diabetes according to American Diabetes Association glucose tolerance criteria. Sensory thresholds were measured by forced-choice techniques. Albumin-to-creatinine ratios were calculated from spot urine samples. RESULTS: Of 90 individuals whose glucose levels were in the range for diabetes, 65 had fasting glucose values >or=126 mg/dl, whereas 25 had 2-h glucose values >or=200 mg/dl, with fasting glucose values <126 mg/dl. In covariance analyses, those with fasting glucose levels >or=126 mg/dl had higher vibration (P < 0.01) and thermal (P < 0.05 for cool and warm) thresholds than those with normal glucose tolerance. This pattern was also evident for albumin-to-creatinine ratios (P < 0.001). In contrast, those with 2-h glucose values >or=200 mg/dl and fasting glucose values <126 mg/dl had sensory threshold and albumin-to-creatinine ratio values similar to those of the normal group. Individuals with fasting glucose levels >or=126 mg/dl had higher vibration threshold and albumin-to-creatinine ratio values (<0.05 and <0.01, respectively) than those with levels <126 mg/dl. CONCLUSIONS: Sensory threshold and albumin excretion values already tend to be greater than normal at screening in individuals with fasting glucose levels >or=126 mg/dl, but not in those with levels <126 mg/dl. A reliance on fasting glucose levels >or=126 mg/dl for screening might not be sufficient for early intervention and the optimal prevention of diabetes complications.     

The prevalence of diabetes and impaired glucose tolerance in Sivas, Central Anatolia, Turkey

OBJECTIVE: The aim of this study was to determine type 2 diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) prevalence in Sivas, Turkey. RESEARCH DESIGN AND METHODS: This cross-sectional study was conducted in the city center of Sivas. The study population of 771 subjects was selected by the cluster sampling method from 115,998 individuals aged > or =30 years. Participants with fasting venous plasma glucose concentrations <100 mg/dl were classified as "normal." Diabetes was diagnosed in participants if they had fasting blood glucose levels > or =126 mg/dl. An oral glucose tolerance test (OGTT) was performed in subjects with fasting blood glucose levels > or =100 mg/dl and <126 mg/dl. RESULTS: According to the fasting blood glucose levels of the 771 subjects, 44 (5.7%) had diabetes. OGTTs were performed in 80 (10.4%) subjects. According to OGTT results, there were 5 subjects with diabetes, 20 subjects with IGT (2.6%), and 55 subjects with IFG (7.1%). The combined prevalence of IFG and IGT was 9.7%. After OGTT, the total number of diabetic subjects was determined to be 49 (6.4%). Twenty-four (3.1%) of the subjects had a previous diagnosis of diabetes. Multivariate analyses showed that age, sex, hypertension, cigarette smoking, obesity, and family history of diabetes were risk factors for type 2 diabetes (P < 0.05). CONCLUSIONS: Diabetes incidence increases with changes in dietary habits and lifestyle. Education is particularly important for public health, as the community may then have required knowledge about the disease and its risk factors.     

Evolution of analytical performance in portable glucose meters in the last decade

OBJECTIVE: To assess and compare the technical accuracy of portable glucose meters during the last decade. RESEARCH DESIGN AND METHODS: One-thousand preprandial (pre) and postprandial (post) capillary whole-blood glucose values measured with meters owned mainly by diabetic patients were compared with a single laboratory method yearly from 1989 to 1999. A total of 21,950 capillary measurements and their corresponding laboratory reference values were analyzed at our clinic. RESULTS: The lowest mean absolute difference was found in 1989 (pre: 2 +/- 22 mg/dl, post: 9 +/- 31 mg/dl) (mean +/- SD). The highest mean absolute difference was observed in 1993 (pre: 31 +/- 33 mg/dl) and 1996 (post: 50 +/- 35 mg/dl). The highest mean relative deviation was observed in 1990 (pre: 16.4%) and 1996 (post: 20.6%). The highest percentage of readings that were within a 5% deviation limit were observed in 1998 (pre: 44.5%) and in 1997 (post: 36.7%). Based on blood glucose levels within +/-5 and +/-10% of laboratory values, the technical accuracy of meters was similar for 1989 and 1999 (P = 0.27 and 0.52, respectively). The percentage of pre values in zone A of Clarke's error grid analysis was >90% in 1989, 1997, 1998, and 1999. CONCLUSIONS: The analytical performance of glucose meters decreased between 1990 and 1996 but was restored between 1997 and 1999. Nevertheless, our data suggest that the technical accuracy of glucose meters has not significantly improved during the last decade. Complementary studies taking into account the preanalytical improvements of the recent meters, as well as their calibration method, appear necessary.     

Continuous subcutaneous glucose monitoring in diabetic patients: a multicenter analysis

OBJECTIVE: To evaluate the accuracy of a new subcutaneous glucose sensor (Glucoday; A. Menarini Diagnostics) compared with venous blood glucose measurement in type 1 and type 2 diabetic patients. RESEARCH DESIGN: A multicenter study was performed in 70 diabetic patients. A microdialysis fiber was inserted subcutaneously into the periumbelical region and perfused with a buffer solution. Glucose concentrations in the dialysate were then measured every 3 min by the glucose sensor over a 24-h period, during which nine venous blood samples were also collected throughout the day. RESULTS: Both the insertion of the fiber and the wearing of the device were well tolerated by the patients. Subcutaneous glucose levels were well correlated with venous glucose measurements (r = 0.9, P < 0.001) over a wide range (40-400 mg/dl) for up to 24 h, with a single-point calibration. An analysis of 381 data pairs showed a linear relationship between the GlucoDay and serial venous blood glucose levels, and 97% of the data fell in the A and B regions of the error grid analysis. Percentage bias between the GlucoDay and the blood venous levels was -2.0% in the hypoglycemic range (<70 mg/dl), 6.9% in the euglycemic range (70-180 mg/dl), and 11.2% in the hyperglycemic range (>180 mg/dl). CONCLUSIONS: The GlucoDay system demonstrated high reliability and reported values that closely agreed with venous blood glucose measurements. The system was well tolerated and thus constitutes a relatively easy method to monitor glucose excursions in diabetic patients.     

Treating postprandial hyperglycemia does not appear to delay progression of early type 2 diabetes: the Early Diabetes Intervention Program

OBJECTIVE: Postprandial hyperglycemia characterizes early type 2 diabetes. We investigated whether ameliorating postprandial hyperglycemia with acarbose would prevent or delay progression of diabetes, defined as progression to frank fasting hyperglycemia, in subjects with early diabetes (fasting plasma glucose [FPG] <140 mg/dl and 2-h plasma glucose > or =200 mg/dl). RESEARCH DESIGN AND METHODS: Two hundred nineteen subjects with early diabetes were randomly assigned to 100 mg acarbose t.i.d. or identical placebo and followed for 5 years or until they reached the primary outcome (two consecutive quarterly FPG measurements of > or =140 mg/dl). Secondary outcomes included measures of glycemia (meal tolerance tests, HbA(1c), annual oral glucose tolerance tests [OGTTs]), measures of insulin resistance (homeostasis model assessment [HOMA] of insulin resistance and insulin sensitivity index from hyperglycemic clamps), and secondary measures of beta-cell function (HOMA-beta, early- and late-phase insulin secretion, and proinsulin-to-insulin ratio). RESULTS: Acarbose significantly reduced postprandial hyperglycemia. However, there was no difference in the cumulative rate of frank fasting hyperglycemia (29% with acarbose and 34% with placebo; P = 0.65 for survival analysis). There were no significant differences between groups in OGTT values, measures of insulin resistance, or secondary measures of beta-cell function. In a post hoc analysis of subjects with initial FPG <126 mg/dl, acarbose reduced the rate of development of FPG > or =126 mg/dl (27 vs. 50%; P = 0.04). CONCLUSIONS: Ameliorating postprandial hyperglycemia did not appear to delay progression of early type 2 diabetes. Factors other than postprandial hyperglycemia may be greater determinants of progression of diabetes. Alternatively, once FPG exceeds 126 mg/dl, beta-cell failure may no longer be remediable.     

Transcutaneous glucose measurement using near-infrared spectroscopy during hypoglycemia

OBJECTIVE: To analyze a transcutaneous near-infrared spectroscopy system as a technique for in vivo noninvasive blood glucose monitoring during euglycemia and hypoglycemia. RESEARCH DESIGN AND METHODS: Ten nondiabetic subjects and two patients with type 1 diabetes were examined in a total of 27 studies. In each study, the subject's plasma glucose was lowered to a hypoglycemia level (approximately 55 mg/dl) followed by recovery to a glycemic level of approximately 115 mg/dl using an intravenous infusion of insulin and 20% dextrose. Plasma glucose levels were determined at 5-min intervals by standard glucose oxidase method and simultaneously by a near-infrared spectroscopic system. The plasma glucose measured by the standard method was used to create a calibration model that could predict glucose levels from the near-infrared spectral data. The two data sets were correlated during the decline and recovery in plasma glucose, within 10 mg/dl plasma glucose ranges, and were examined using the Clarke Error Grid Analysis. RESULTS: Two sets of 1,704 plasma glucose determinations were examined. The near-infrared predictions during the fall and recovery in plasma glucose were highly correlated (r = 0.96 and 0.95, respectively). When analyzed during 10 mg/dl plasma glucose segments, the mean absolute difference between the near-infrared spectroscopy method and the chemometric reference ranged from 3.3 to 4.4 mg/dl in the nondiabetic subjects and from 2.6 to 3.8 mg/dl in the patients with type 1 diabetes. Using the Error Grid Analysis, 97.7% of all the near-infrared predictions were assigned to the A-zone. CONCLUSIONS: Our findings suggest that the near-infrared spectroscopy method can accurately predict plasma glucose levels during euglycemia and hypoglycemia in humans.     

Accuracy of bedside capillary blood glucose measurements in critically ill patients

OBJECTIVE: To compare the accuracy of fingerstick with laboratory venous plasma glucose measurements (laboratory glucose) in medical ICU patients and to determine the factors which interfere with the accuracy of fingerstick measurements. PARTICIPANTS: The study included 80 consecutive patients aged 58+/-7 years, BMI 29.5+/-9.0, and APACHE II score 15+/-6 (277 simultaneous paired measurements). MEASUREMENTS: This prospective observational study compared fingerstick measurements to simultaneously sampled laboratory glucose once a day in patients in our medical ICU (twice daily if on an insulin infusion). Data recorded included patient demographics, admission diagnoses, APACHE II score, BMI, daily hematocrit, arterial blood gasses, chemistry results, concomitant medications (including vasopressors and corticosteroids), and upper extremity edema. Accuracy was defined as the percentage of paired values not in accord (>15 mg dl(-1)/ 0.83 mmol(-1)l(-1) difference for laboratory values <75 mg dl(-1)/4.12 mmol(-1)l(-1) and >20% difference for laboratory values >or=75 mg/dl). Outliers (blood glucose difference >100 mg dl(-1)/5.56 mmol(-1) l(-1)) were excluded from the correlation and distribution analyses. RESULTS: Mean fingerstick glucose was 129+/-45 mg/dl (7.2+/-2.5 mmol/l) and mean laboratory glucose 123+/-44 mg/dl (6.8+/-2.4 mmol/l). The correlation coefficient between the two values was 0.9110 (Clinical and Laboratory Standards Institute threshold 0.9751). The mean difference (bias) between the two methods was 8.6+/-18.6 mg/dl (0.48+/-1.0 mmol/l) and limits of agreement +45.8 and -28.6 mg/dl (+2.5 and -1.6 mmol/l). Fifty-three (19%) paired measurements in 22 patients were not in accord (CLSI threshold 相似文献   

Noninvasive glucose monitoring in diabetic patients: a preliminary evaluation.

Noninvasive monitoring of blood/tissue glucose concentrations has been successfully accomplished in individual diabetic subjects by using near-infrared (NIR) spectroscopy coupled with chemometric methods. Three different spectrometer configurations were tested: a) a Fourier-transform infrared spectrometer with an indium antimonide detector; b) a grating monochromator equipped with a silicon (Si) array detector, without fiber optics; and c) a grating monochromator equipped with an Si detector, with fiber-optic sampling. NIR spectra were obtained from diabetic subjects by transmission through the finger during a meal-tolerance test. The maximum range of observed plasma glucose concentrations obtained from the blood samples was 2.5-27 mmol/L. The NIR spectra were processed by using the chemometric multivariate calibration methods of partial least squares and principal component regression. The best calibration yielded a cross-validated average absolute error in glucose concentration of 1.1 mmol/L. This predictive ability suggests that noninvasive glucose determinations by NIR/chemometrics is a viable analytical method.     

Noninvasive blood glucose monitoring with optical coherence tomography: a pilot study in human subjects

OBJECTIVE: To study the feasibility of noninvasive blood glucose monitoring using optical coherence tomography (OCT) technique in healthy volunteers. RESEARCH DESIGN AND METHODS: An OCT system with the wavelength of 1,300 nm was used in 15 healthy subjects in 18 clinical experiments. Standard oral glucose tolerance tests were performed to induce changes in blood glucose concentration. Blood samples were taken from the right arm vein every 5 or 15 min. OCT images were taken every 10-20 s from the left forearm over a total period of 3 h. The slope of the signals was calculated at the depth of 200-600 micro m from the skin surface. RESULTS: A total of 426 blood samples and 8,437 OCT images and signals were collected and analyzed in these experiments. There was a good correlation between changes in the slope of noninvasively measured OCT signals and blood glucose concentrations throughout the duration of the experiments. The slope of OCT signals changed significantly (up to 2.8% per 10 mg/dl) with variation of plasma glucose values. The good correlation obtained between the OCT signal slope and blood glucose concentration is due to the coherent detection of backscattered photons, which allows measurements of OCT signal from a specific tissue layer without unwanted signal from other tissue layers. CONCLUSIONS: This pilot study demonstrated the capability of the OCT technique to monitor blood glucose concentration noninvasively in human subjects. Further studies with a larger number of subjects including diabetic subjects are planned to validate these preliminary results.     

Improvement in glycemic excursions with a transcutaneous, real-time continuous glucose sensor: a randomized controlled trial

OBJECTIVE: Hypoglycemia and wide glucose excursions continue to be major obstacles to achieving target HbA(1c) values and the associated reductions in long-term complications (and economic costs) in people with insulin-treated diabetes. In this study we evaluated the accuracy, safety, and clinical effectiveness of a continuous glucose-sensing device. RESEARCH DESIGN AND METHODS: A total of 91 insulin-requiring patients with type 1 (n = 75) and type 2 (n = 16) diabetes were enrolled in this multicenter randomized study. Subjects wore a transcutaneous, 3-day, continuous glucose-sensing system for three consecutive 72-h periods. Subjects were randomly assigned (1:1 ratio) to either a control group (continuous glucose data not provided) or a display group (continuous glucose data not provided during period 1 but displayed during periods 2 and 3). During periods 2 and 3, patients in the display group had real-time access to sensor glucose values, could review glucose trends over the preceding 1, 3, and 9 h, and were provided with high (> or = 200 mg/dl) and low (< or = 80 mg/dl) alerts and a low (< or = 55 mg/dl) alarm. Sensors were inserted by patients, and both groups used (or wore) the system during daily activities. Device accuracy was assessed by comparing continuous glucose values to paired self-monitoring of blood glucose (SMBG) meter readings. Clinical effectiveness was evaluated by analyzing between-group (control vs. display, periods 2 and 3) and within-group (display, period 1 vs. period 3) differences in time spent in high, low, and target (81-140 mg/dl) glucose zones. RESULTS: When prospective, real-time sensor values were compared with SMBG values, 95.4% of 6,767 paired glucose values fell within Clarke error grid A and B zones. Pearson's correlation coefficient was 0.88, and mean and median absolute relative differences were 21.2 and 15.9%, respectively. No systematic bias was detected at any of the prespecified glucose levels (50, 80, 100, 150, and 200 mg/dl). When compared with control subjects, the display group spent 21% less time as hypoglycemic (<55 mg/dl), 23% less time as hyperglycemic (> or = 240 mg/dl), and 26% more time in the target (81-140 mg/dl) glucose range (P < 0.001 for each comparison). Nocturnal (10:00 p.m. to 6:00 a.m.) hypoglycemia, as assessed at two thresholds, was also reduced by 38% (<55 mg/dl; P < 0.001) and 33% (55-80 mg/dl; P < 0.001) in the display group compared with control subjects. CONCLUSIONS: We conclude that real-time continuous glucose monitoring for periods up to 72 h is accurate and safe in insulin-requiring subjects with type 1 and type 2 diabetes. This study demonstrates that availability of real-time, continuously measured glucose levels can significantly improve glycemic excursions by reducing exposure to hyperglycemia without increasing the risk of hypoglycemia, which may reduce long-term diabetes complications and their associated economic costs.     

HbA1c measurement improves the detection of type 2 diabetes in high-risk individuals with nondiagnostic levels of fasting plasma glucose: the Early Diabetes Intervention Program (EDIP)

OBJECTIVE: Whereas new diagnostic criteria based on a fasting plasma glucose (FPG) of > 126 mg/dl (7.8 mmol/l) have improved the detection of diabetes, multiple reports indicate that many people with diabetes diagnosed by 2-h oral glucose tolerance test (OGTT) glucose measurements > or = 11.1 mmol/l (200 mg/dl) would remain undiagnosed based on this FPG criteria. Thus, improved methods to detect diabetes are particularly needed for high-risk individuals. We evaluated whether the combination of FPG and HbA1c measurements enhanced detection of diabetes in those individuals at risk for diabetes with nondiagnostic or minimally elevated FPG. RESEARCH DESIGN AND METHODS: We analyzed FPG, OGTT, and HbA1c data from 244 subjects screened for participation in the Early Diabetes Intervention Program (EDIP). RESULTS: Of 244 high-risk subjects studied by FPG measurements and OGTT, 24% of the individuals with FPG levels of 5.5-6.0 mmol/l (100-109 mg/dl) had OGTT-diagnosed diabetes, and nearly 50% of the individuals with FPG levels of 6.1-6.9 mmol/l (110-125 mg/dl) had OGTT-diagnosed diabetes. In the subjects with OGTT-diagnosed diabetes and FPG levels between 5.5 and 8.0 mmol/l, detection of an elevated HbA1c (>6.1% or mean + 2 SDs) led to a substantial improvement in diagnostic sensitivity over the FPG threshold of 7.0 mmol/l (61 vs. 45%, respectively, P = 0.002). Concordant FPG levels > or = 7.0 mmol/l (currently recommended for diagnosis) occurred in only 19% of our cohort with type 2 diabetes. CONCLUSIONS: Diagnostic criteria based on FPG criteria are relatively insensitive in the detection of early type 2 diabetes in at-risk subjects. HbA1c measurement improves the sensitivity of screening in high-risk individuals.     

The evaluation of analytical performance of the Precision G point-of-care glucometer.

In this study analytical and functional performance of the Precision G "point-of-care" glucometer (MediSense Inc.) was evaluated. Studies were carried-out using capillary blood collected for routine monitoring of glycemia in diabetic patients. Each glucose test measurement with the glucometer was paralleled by the laboratory measurement of glucose on the same blood sample, using the GOD/PAP method. Mean accuracy error in the glucose concentration range of 1.1-33.3 mmol/l calculated for the glucometer vs. the laboratory method amounted to only 0.2%. However, for glucose concentrations below 4.4 mmol/l the mean accuracy error was 3.9%, and for the concentrations above 10.0 mmol/l it was 4.6%. Within-run CV for three concentration levels was 2.76%, 2.89%, and 4.22%, respectively. Linearity of the meter response in samples with glucose concentration ranging from 1.7 mmol/l to 16.7 mmol/l, expressed as the correlation coefficient r, yielded r=0.996 and linear regression equation [y1 = 0.996 y2 - 0.005], where y1 is the measured glucose concentration and y2 is the target glucose concentration calculated in diluted samples. Correlation studies on a set of 114 blood samples collected from patients and assayed by glucometer and by the laboratory method yielded a relationship expressed by the equation: y = 0.84x + 1.13 where y is glucometer read-out and x is glucose concentration obtained by the laboratory method. Passing-Bablok test showed a significant agreement between the glucometer measurements and the reference laboratory results in the studied glucose concentration range. The error grid analysis of series of the paired patient's samples showed that 95% of results were in the clinically acceptable zone A and 1% of results in zone D.     

Lactate analyzer with continuous blood sampling for monitoring blood lactate during physical exercise

To monitor changes in the concentration of blood lactate during physical exercise, we used an automated lactate analyzer based on an electro-enzymatic method with continuous blood sampling through a catheter. The lactate concentration was measured every 2 min; between measurements, the instrument was calibrated with a lactate standard. Ascorbic acid, bilirubin, hemoglobin, creatinine, uric acid, and glucose did not interfere with the measurements. The lactate concentrations in blood samples from apparently healthy subjects before and after exercise correlated well (r = 0.993) with results by the conventional enzymatic method. We measured the blood lactate concentrations in nine apparently healthy volunteers during exercise on a treadmill with an increasing workload. The point at which lactate concentrations started to increase was detected easily. Thus, the lactate analyzer is suitable for monitoring changes in blood lactate concentrations during exercise.     

Presence of diabetes risk factors in a large U.S. eighth-grade cohort

OBJECTIVE: The study was conducted in 12 middle schools to determine the prevalence of diabetes, pre-diabetes, and diabetes risk factors in eighth-grade students who were predominantly minority and evaluate the feasibility of collecting physical and laboratory data in schools. RESEARCH DESIGN AND METHODS: Anthropometric measurements and fasting and 2-h post-glucose load blood draws were obtained from approximately 1,740 eighth-grade students. RESULTS: Mean recruitment rate was 50% per school, 49% had BMI > or = 85th percentile, 40.5% had fasting glucose > or = 100 mg/dl, 0.4% had fasting glucose > or = 126 mg/dl, and 2.0% had 2-h glucose > or = 140 mg/dl and 0.1% > or = 200 mg/dl. Mean fasting insulin value was 30.1 microU/ml, 36.2% had fasting insulin > or = 30 microU/ml, and 2-h mean insulin was 102.1 microU/ml. Fasting and 2-h glucose and insulin values increased across BMI percentiles, and fasting glucose was highest in Hispanic and Native American students. CONCLUSIONS: There was a high prevalence of risk factors for diabetes, including impaired fasting glucose (> or =100 mg/dl), hyperinsulinism suggestive of insulin resistance (fasting insulin > or = 30 microU/ml), and BMI > or = 85th percentile. These data suggest that middle schools are appropriate targets for population-based efforts to decrease overweight and diabetes risk.     

In vitro measurements of physiological glucose concentrations in biological fluids using mid-infrared light

Mid-infrared transmission spectroscopy using broadband mid-infrared or Quantum Cascade laser sources is used to predict glucose concentrations of aqueous and serum solutions containing physiologically relevant amounts of glucose (50-400 mg/dL). We employ partial least squares regression to generate a calibration model using a subset of the spectra taken and to predict concentrations from new spectra. Clinically accurate measurements with respect to a Clarke error grid were made for concentrations as low as 30 mg/dL, regardless of background solvent. These results are an important and encouraging step in the work towards developing a noninvasive in vivo glucose sensor in the mid-infrared.OCIS codes: (170.1470) Blood or tissue constituent monitoring, (300.1030) Absorption, (300.6340) Spectroscopy, infrared     

Correlation of fingerstick blood glucose measurements with GlucoWatch biographer glucose results in young subjects with type 1 diabetes.

OBJECTIVE: The purpose of this study was to compare measurements of glucose obtained via iontophoretic extraction with the GlucoWatch automatic glucose biographer (Cygnus, Inc., Redwood City, CA) with capillary blood glucose values that were determined 1) in a controlled outpatient clinic setting and 2) in a home setting. RESEARCH DESIGN AND METHODS: There were 76 GlucoWatch biographers used on 28 different young adults (21 women and 7 men) with type 1 diabetes (age 30.9 +/- 6.9 years and duration of diabetes 18.4 +/- 8.1 years [mean +/- SD]) in a controlled outpatient clinic setting. Some subjects participated on multiple days. Subjects wore two GlucoWatch biographers, each on the forearm (ventral aspect). Comparisons were made to HemoCue blood glucose analyzer (Aktiebolgat Leo, Helsingborg, Sweden) capillary blood glucose measurements. In addition, GlucoWatch biographers (one each day for 3 consecutive days) were used by 12 subjects (8 women, 4 men) in a home setting. Comparisons were made to capillary blood glucose values determined using the One Touch Profile meter (Johnson & Johnson, New Brunswick, NJ). RESULTS: GlucoWatch biographer glucose values correlated well with capillary blood glucose values determined using the HemoCue analyzer in the clinic setting (r = 0.90, 1,554 paired data points) and using the One Touch Profile meter in the home setting (r = 0.85, 204 paired data points). When 36 subjects wore two biographers simultaneously, the correlation between the two biographers was r = 0.94. The error grid analysis demonstrated that > 96% of biographer glucose values determined in the clinic or home setting were in the clinically acceptable A and B regions. CONCLUSIONS: This study confirms the accuracy and precision of glucose values as determined using the GlucoWatch biographer in clinic and home settings.     

Performance of recommended screening tests for undiagnosed diabetes and dysglycemia.

OBJECTIVE: To evaluate the performance, in settings typical of opportunistic and community screening programs, of screening tests currently recommended by the American Diabetes Association (ADA) for detecting undiagnosed diabetes. RESEARCH DESIGN AND METHODS: Volunteers aged > or =20 years without previously diagnosed diabetes (n = 1,471) completed a brief questionnaire and underwent recording of postprandial time and measurement of capillary blood glucose (CBG) with a portable sensor. Participants subsequently underwent a 75-g oral glucose tolerance test; fasting serum glucose (FSG) and 2-h postload serum glucose (2-h SG) concentrations were measured. The screening tests we studied included the ADA risk assessment questionnaire, the recommended CBG cut point of 140 mg/dl, and an alternative CBG cut point of 120 mg/dl. Each screening test was evaluated against several diagnostic criteria for diabetes (FSG > or =126 mg/dl, 2-h SG > or =200 mg/dl, or either) and dysglycemia (FSG > or =110 mg/dl, 2-h SG > or =140 mg/dl, or either). RESULTS: Among all participants, 10.7% had undiagnosed diabetes (FSG > or =126 or 2-h SG > or =200 mg/dl), 52.1% had a positive result on the questionnaire, 9.5% had CBG > or =140 mg/dl, and 18.4% had CBG > or =120 mg/dl. The questionnaire was 72-78% sensitive and 50-51% specific for the three diabetes diagnostic criteria; CBG > or =140 mg/dl was 56-65% sensitive and 95-96% specific, and CBG > or =120 mg/dl was 75-84% sensitive and 86-90% specific. CBG > or =120 mg/dl was 44-62% sensitive and 89-90% specific for dysglycemia. CONCLUSIONS: Low specificity may limit the usefulness of the ADA questionnaire. Lowering the cut point for a casual CBG test (e.g., to 120 mg/dl) may improve sensitivity and still provide adequate specificity.     

The effects of aerobic exercise on glucose and counterregulatory hormone concentrations in children with type 1 diabetes

OBJECTIVE: To examine the acute glucose-lowering effects of aerobic exercise in children and adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Fifty children and adolescents with type 1 diabetes (ages 10 to <18 years) were studied during exercise. The 75-min exercise session consisted of four 15-min periods of walking on a treadmill to a target heart rate of 140 bpm and three 5-min rest periods. Blood glucose and plasma glucagon, cortisol, growth hormone, and norepinephrine concentrations were measured before, during, and after exercise. RESULTS: In most subjects (83%), plasma glucose concentration dropped at least 25% from baseline, and 15 (30%) subjects became hypoglycemic (< or = 60 mg/dl) or were treated for low glucose either during or immediately following the exercise session. The incidence of hypoglycemia and/or treatment for low glucose varied significantly by baseline glucose, occurring in 86 vs. 13 vs. 6% of subjects with baseline values <120, 120-180, and >180 mg/dl, respectively (P < 0.001). Exercise-induced increases in growth hormone and norepinephrine concentrations were marginally higher in subjects whose glucose dropped < or = 70 mg/dl. Treatment of hypoglycemia with 15 g of oral glucose resulted in only about a 20-mg/dl rise in glucose concentrations. CONCLUSIONS: In youth with type 1 diabetes, prolonged moderate aerobic exercise results in a consistent reduction in plasma glucose and the frequent occurrence of hypoglycemia when preexercise glucose concentrations are <120 mg/dl. Moreover, treatment with 15 g of oral glucose is often insufficient to reliably treat hypoglycemia during exercise in these youngsters.     

Pulse wave velocity as an indicator of atherosclerosis in impaired fasting glucose: the Tanno and Sobetsu study

OBJECTIVE: Brachial-ankle pulse wave velocity (baPWV), as an indicator of atherosclerosis in impaired fasting glucose (IFG), was studied in 232 subjects randomly selected from inhabitants of two rural communities in Japan. RESEARCH DESIGN AND METHODS: BMI, systolic blood pressure (SBP), fasting blood glucose (FBS), lipid parameters, ankle brachial pressure index (ABI), and baPWV were measured in each subject. ABI and baPWV were measured using the recently developed device, form ABI/PWV. The subjects were divided into three groups according FBS level: a normal group consisting of subjects with FBS <110 mg/dl, an IFG group consisting of subjects with FBS 110-125 mg/dl, and a diabetic group consisting of subjects with FBS > or =126 mg/dl and subjects taking hypoglycemic agents. The parameters in the three groups were compared. RESULTS-It was found that the baPWV value increased with increasing plasma glucose level. Significant differences were found between the baPWV values in the normal and IFG groups (1,518 vs. 1,673 cm/s, P = 0.01) and in the normal and diabetic groups (1,518 vs. 1,771 cm/s, P < 0.0001). The results of multiple regression analysis showed that FBS was closely related to baPWV as well as to age and SBP. CONCLUSIONS: The relationship between IFG and atherosclerosis remains controversial. Further studies are needed to evaluate whether strict control of blood glucose level in patients with IFG will result in the prevention of atherosclerosis progression.     

Clinical performance of CGMS in type 1 diabetic patients treated by continuous subcutaneous insulin infusion using insulin analogs

OBJECTIVE: Performance criteria have been established for in vitro blood glucose monitoring, particularly for the self-monitoring of blood glucose using glucose meters. Devices intended for use in the future, such as the continuous glucose monitoring system (CGMS), should satisfy similar criteria, particularly in diabetic patients under intensive therapy. RESEARCH DESIGN AND METHODS: The analysis was conducted on 18 type 1 diabetic patients (not controlled, HbA(1c) >7.5%) treated by external pump using insulin analogs. Each patient received a glucose sensor for 3 days during his/her hospitalization and was instructed in its operation. Medtronic criteria were used to determine the accuracy of the CGMS. In addition, the data were analyzed according to American Diabetes Association (ADA) criteria, Clarke Error Grid analysis, and method of residuals, with the glucose oxidase method using a Beckman analyzer used as the reference method. Specificity and sensitivity were evaluated from the viewpoint of accuracy in the detection of hypoglycemia. For nine patients, two glucose sensors were simultaneously inserted into an abdominal site to determine the reproducibility of the system. RESULTS-Among the 33 glucose sensors inserted, 6 (18%) were nonfunctional. The mean duration of CGMS recording was 63 +/- 12 h. From all of the 692 sets of data that paired glucose readings and CGMS, the coefficients of correlation ranged from 0.87 to 0.92 and the mean absolute error ranged from 12.8 to 15.7%. The time experienced in hypoglycemia (<55 mg/dl) was reported at 86 +/- 62 min/day. Only 39% of the CGMS values satisfied the ADA precision criteria to within +/-10%, and 19% of these values satisfied the future ADA precision criteria of accuracy to within +/-5%. The means of difference method showed that the CGMS slightly underestimated the plasma glucose values (mean = -12 mg/dl). Error grid analysis showed only 77% of the glucose sensor values were in zone A, and 98.9% were in zones A and B. Two values fell in zone C and a single value fell in zone D. The sensitivity and specificity of the CGMS to detect hypoglycemia were 33 and 96%, respectively. A total of 6666 paired sensor values were recorded with a coefficient of correlation of 0.84 with a coefficient of variation of 8.25%. CONCLUSIONS: CGMS could be useful in routine clinical practice to provide much more information on the glucose profile than intermittent self-monitoring of blood glucose (SMBG). However, CGMS cannot be used as a replacement for glucose meters because it does not satisfy the conventional performance goals set down for in vitro glucose measurements and could therefore lead to clinically incorrect treatment decisions.