Showing papers on "Glucose Measurement published in 2007"

Short-term Variability in Measures of Glycemia and Implications for the Classification of Diabetes

Abstract: Background 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 A 1c (HbA 1c ) levels and to assess the impact of using repeated measurements for classification of diabetes. Methods 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. Results 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 HbA 1c (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. Conclusions We found high variability in 2-hour glucose levels relative to fasting glucose levels and high variability in both of these relative to HbA 1c 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.

Accuracy of bedside capillary blood glucose measurements in critically ill patients

Abstract: 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. 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). 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 20% difference for laboratory values ≥ 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. 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 ≤ 5%). In 44 (83%) of these paired measurements fingerstick glucose was greater than laboratory glucose. The findings suggest that capillary blood glucose as measured by fingerstick is inaccurate in critically ill ICU patients and does not meet the CLSI standard. It is unclear whether the sampling method, device used, or both contributed to this inaccuracy. The wide limits of agreement suggest that fingerstick measurements should be used with great caution in protocols of tight glycemic control.

A flexible and wearable biosensor for tear glucose measurement

Abstract: A flexible and wearable amperometoric glucose sensor was fabricated and tested. Also, the sensor was utilized to tear glucose monitoring. The sensor was constructed by immobilizing GOD onto a flexible oxygen electrode (Pt working electrode and Ag/AgCl counter/reference electrode), which was fabricated using "Soft-MEMS" techniques onto a functional polymer membrane. In purpose of bioinstrumentation, adhesive agents were not used for constructing the flexible biosensor. Linear relationship between glucose concentration and output current was obtained in a range of 0.025-1.475 mmol/l, with a correlation coefficient of 0.998. Current dependences on pH and temperature were also evaluated. The current was largest at pH 7.0 and the current increased when temperature increased. This indicates that the output current depends on enzyme activity. Based on the basic characteristics investigation, the glucose sensor was applied to measurement of glucose in tear fluids on an eye site of a Japan white rabbit. The change of tear glucose level induced by oral-administration of glucose was monitored as a current change of the sensor attached on the eye site. In this investigation, the tear glucose level varied from 0.16 to 0.46 mmol/l. Although there was a delay of several tens of minutes towards blood sugar level, it is considered to be possible that non-invasive continuous glucose monitoring can be realized using the flexible biosensor.

Patches, systems, and methods for non-invasive glucose measurement

Abstract: Described here are patches, systems, and methods for measuring glucose. In general, the patches comprise a microfluidic collection layer and a detector, and the systems comprise a patch and a measurement device. Some methods for measuring glucose comprise cleaning the skin surface, collecting sweat from the skin surface using a microfluidic collection device, and measuring the collected glucose. Other methods comprise cleaning the skin surface, collecting sweat in a patch comprising a microfludic collection layer, and measuring glucose collected in the patch. Still other methods comprise cleaning the skin surface, collecting a first sweat sample from the skin surface in a patch comprising a microfludic collection layer and a detector layer, transferring the first sweat sample from the collection layer to the detector layer, measuring glucose in the first sweat sample, and repeating the collection, transferring, and measuring steps at least once.

Mass Spectral Determination of Fasting Tear Glucose Concentrations in Nondiabetic Volunteers

Abstract: Background: There is considerable disagreement regarding the concentration of glucose in tears and its relationship to the concentration in blood. Improved sampling and analysis methods may resolve these discrepancies and possibly provide a basis for in situ tear glucose sensors. Methods: We used liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) to determine glucose in 1-μL tear fluid samples obtained from 25 fasting study participants. Tear fluid was collected with microcapillaries and a slitlamp microscope. Results: The median (range) of fasting tear glucose concentrations was 28 (7–161) μmol/L or 0.50 (0.13–2.90) mg/dL. The SD of tear glucose measurements for individuals varied linearly with the mean tear glucose concentration and was approximately half of the mean. We found no significant difference in tear glucose concentrations between contact lens users and nonusers ( P = 0.715). We observed significant correlations between fasting blood and tear glucose concentrations ( R = 0.50, P = 0.01). Conclusions: Our tear fluid collection and analysis method enables reliable measurement of equilibrium, fasting tear glucose concentrations. These concentrations are lower than those previously reported for nondiabetic persons. Larger population studies are required to determine correlations between blood and tear glucose concentrations and to determine the utility of contact lens–based sensors for the monitoring of diabetes. Our methods are applicable for study of other tear fluid analytes and may prove useful for monitoring other disease states.

Selectivity assessment of noninvasive glucose measurements based on analysis of multivariate calibration vectors.

Abstract: Background: Selectivity is paramount for the successful implementation of noninvasive spectroscopic sensing for the painless measurement of blood glucose concentrations in people with diabetes. Selectivity issues are explored for different multivariate calibration models based on noninvasive near-infrared spectra collected from an animal model. Methods: Noninvasive near-infrared spectra are collected through a fiber-optic interface attached to a thin fold of skin on the back of an anesthetized laboratory rat while glucose levels are varied in a controlled manner. Results and Discussion: Partial least-squares (PLS) calibration models are generated from noninvasive spectra collected during a single, 2-hour blood glucose transient. Calibration vectors are compared for optimized PLS calibration models created with correct and incorrect assignments of glucose concentrations to each noninvasive spectrum. Although both PLS models appear functional and seem capable of predicting glucose concentrations accurately during this transient, only the model generated from correct glucose assignments gives a credible calibration vector. When correct glucose assignments are used, the PLS calibration vector matches the corresponding net analyte signal calibration vector. No similarity in these calibration vectors is evident when incorrect glucose assignments are used. Conclusions: Glucose-specific spectral information is present within noninvasive near-infrared spectra collected from a rat model using a transmission geometry. Apparently functional, yet incorrect, calibration models can be generated, and the propensity to create such false PLS calibration models calls into question the validity of past reports. An analysis of calibration vectors can provide valuable insight into the chemical basis of selectivity for multivariate calibration models of complex systems.

Introduction and evaluation of a computerised insulin protocol.

Abstract: To lower glucose levels in all patients in the intensive care unit (ICU) to the target range of 4.5–7.5 mmol/l using a nurse-driven computerised insulin protocol in combination with bedside glucose measurement. Cohort study. Mixed adult ICU. All 182 patients admitted to the ICU during a 3-month period were studied, except for 3 patients admitted for diabetic keto-acidosis. Five steps were taken to improve glucose regulation: (1) Nurses were authorised to adjust insulin dosage using a protocol. (2) Glucose was measured more often. (3) Glucose was measured at the bedside. (4) Consecutive protocols aimed for successively lower glucose levels; the final protocol had a target range of 4.5–7.5 mmol/l. (5) The protocol was computerised. Mean glucose decreased from 9.23 mmol/l without protocol to 7.68 mmol/l with the final protocol. This final protocol with the target of 4.5–7.5 mmol/l was evaluated more extensively. Glucose levels were measured a total of 1854 times in 179 ICU admissions during 552 ICU treatment days. The median glucose level was 7.0 mmol/l, and 53.1% of glucose measurements were within the target range of 4.5–7.5 mmol/l. One episode of hypoglycaemia (glucose ≤ 2.2 mmol/l) occurred, representing 0.5% of patients or 0.05% of glucose measurements. The combined strategy of successively more ambitious nurse-driven (computerised) insulin protocols and bedside glucose measurement resulted in acceptably low glucose levels with very few episodes of hypoglycaemia.

Adherence to and efficacy and safety of an insulin protocol in the critically ill: a prospective observational study.

Abstract: Background Blood glucose control during acute illness has been associated with improved-outcomes. Objectives To evaluate adherence to and efficacy and safety of an insulin protocol for critically ill patients with target blood glucose levels between 81 and 110 mg/dL and to determine factors associated with adequate daily blood glucose control. Methods In a prospective observational study, blood glucose levels were determined in 30 patients in intensive care units of a tertiary care university hospital during a 2-month period. All glucose measurements and corresponding insulin infusion rates were evaluated for adherence to and efficacy and safety of the insulin protocol. Linear regression analysis was used to deter mine factors associated with adequate daily blood glucose control, defined as time in the target range. Results A total of 6016 blood glucose measurements were obtained during 352 protocol implementation days. Adherence to the protocol was 71%. Blood glucose levels were in the desired range 42% of the total protocol implementation time. Sixty percent of the patients experienced at least one hypoglycemic. event. Adherence to the protocol (P < .001), high bilirubin level (P < .001), low daily insulin dose (P = .002), and low C-reactive protein level (P = .048) were independently associated with adequate daily blood, glucose control.. Conclusions Protocol adherence was positively associated with daily time in the target range, but efficacy during the total protocol implementation time remained poor. Because of the frequency of hypoglycemia, protocols to maintain blood glucose levels between 81 and 110 mg/dL in critically ill patients may not be recommended.

Evaluation of Inaccuracies in the Measurement of Glycemia in the Laboratory, by Glucose Meters, and Through Measurement of Hemoglobin A1c

Abstract: IN BRIEF The accurate measurement of glucose is extremely important in the diagnosis of diabetes and pre-diabetes, where the laboratory values are crucial; in the management of diabetes, where glucose meter values are crucial; and in attainment of goals in diabetes, where hemoglobin A 1c measurement is crucial. This article reviews pitfalls that may interfere with accuracy of glucose measurement in each of these three areas and how this inaccuracy may be evaluated and managed in the primary care setting. Three case presentations of disparity are discussed.

Practical issues in the identification of empirical models from simulated type 1 diabetes data.

Abstract: Background: A model-based controller for an artificial β-cell automatically regulates blood glucose levels based on available glucose measurements, insulin infusion and meal information, and model ...

Blood glucose monitoring systems

Abstract: This invention relates to apparatus, methods and computer program code for blood glucose monitoring, more particularly for determining times of blood glucose measurement. An apparatus for determining times of blood glucose measurement of a subject for use in controlling a level of said blood glucose, the apparatus comprising: an input to receive blood glucose measurement data for a series of blood glucose measurements; an adaptive model responsive to said blood glucose measurement data to represent the glucoregulation of said subject; an estimator of a prediction error in said adaptive model as a function of time; and a system to determine a time of a glucose measurement based on a comparison of said time-dependent prediction error with a range of acceptable blood glucose level for said subject.

Reliability assessment of glucose measurement by HemoCue analyser in a neonatal intensive care unit.

Abstract: Background Rapid and reliable bed-side determination of blood glucose concentration is very important in the management of acutely ill infants and especially in premature newborns. HemoCue is an easy-to-use glucose analyser. The aim of the present study was to examine the usefulness of the HemoCue glucose analyser compared to a reference plasma glucose method (SYS, BM/Hitachi 747/737) in a neonatal intensive care unit (NICU). Methods Seventy-eight consecutive neonates admitted to our NICU were enrolled in the study. At the time of the study all patients were grouped according to nutritional management (parenteral or enteral nutrition), haematocrit values and birth weight. The effects of feeding management, haematocrit values, and birth weight on accuracy and precision of the device were evaluated. Results Overall data linear regression analysis yielded an r-value of 0.905 and the Bland-Altman method demonstrated that HemoCue overestimates plasma glucose by 0.932 mmol/L. Evaluation of our data by receiver operating characteristic curve demonstrated 100% sensitivity cutoff at 4.1 mmol/L. Conclusions HemoCue cannot be used satisfactorily in the management of glycaemia in the NICU. In the preterm population, birth weight had a dramatic influence on HemoCue accuracy. Low haematocrit and parenteral feeding further contributed to a decrease in the accuracy of this device.

Correlation between hemoglobin A1c (HbA1c) and average blood glucose: can HbA1c be reported as estimated blood glucose concentration?

Abstract: Glycation is the nonenzymatic addition of sugar to amino groups of proteins. While virtually any protein in the body can be glycated, for convenience and ease of obtaining a sample, glycated hemoglobin is measured in the blood obtained from a patient. Blood glucose concentrations exhibit wide diurnal fluctuations due to food ingestion, exercise, and other factors. In contrast, the concentration of glycated hemoglobin remains relatively stable with time. This is due to the life span of red blood cells, which is usually ∼120 days. In individuals with a normal erythrocyte life span, glycated hemoglobin is directly proportional to the blood glucose concentration over the preceding 8 to 12 weeks.1 In patients with diabetes mellitus, the glycated hemoglobin value is used to determine the degree of glycemic control and to make decisions regarding therapy.2,3 In addition, the concentration of glycated hemoglobin predicts the progression of diabetic microvascular complications. This has been clearly documented by randomized, multicenter studies in patients with type 14 and type 25 diabetes. More recent evidence indicates that glycated hemoglobin also predicts cardiovascular disease in patients with type 1 diabetes.6 Measurement of glycated hemoglobin is thus an essential component in the management of patients with diabetes. There are several forms of glycated hemoglobin. These include hemoglobin A1c (HbA1c), HbA1 (which comprises HbA1a, HbA1b, and HbA1c), and total glycated hemoglobin (which comprises HbA1 plus other glycated hemoglobin species). Both the Diabetes Complications and Control Trial (DCCT) and the United Kingdom Prospective Diabetes Study measured HbA1c.4,5 Thus, most clinical outcome data that relate glycemic control to the complications of diabetes are based on HbA1c measurement. The American Diabetes Association (ADA) recommends that HbA1c should be measured at least twice a year in persons with diabetes.1,2 Retrospective analysis of data derived from self-monitoring of blood glucose by patients in the DCCT identified a linear correlation between HbA1c and average blood glucose concentrations.7 Although the number of subjects enrolled was large, the DCCT was not designed to determine average blood glucose and the patient population was limited to individuals with type 1 diabetes. A number of other studies have also examined this relationship,8–10 but are limited by the inclusion of relatively few subjects and few glucose assays. Therefore, a large multinational study is being conducted to establish whether average blood glucose concentration correlates with HbA1c and, if so, to determine a conversion factor. The study is named ADAG, for estimated A1c-derived average glucose. The planned study group comprises 700 individuals (300 with type 1 diabetes, 300 with type 2 diabetes, and 100 healthy subjects). Subjects have been recruited in several different countries to obtain diverse racial and ethnic representations. Individuals with different HbA1c concentrations, namely 4–6.5%, 6.6–8.5%, and >8.5% (reference range for HbA1c is 4–6%), have been targeted. HbA1c was measured monthly with all analyses performed in a single laboratory to minimize assay variation. It is more difficult to accurately measure average blood glucose than HbA1c. In order to evaluate average glucose, all study participants underwent continuous glucose monitoring (CGM) (using a MiniMed device) for 48 hours every month for 4 months. During CGM, subjects perform an eight-point assessment of blood glucose using a HemoCue meter. In addition, all participants measured their blood glucose concentration seven times per day, at least 3 days per week, for the entire duration of the 12-week study. Thus, over 2500 glucose measurements were performed in each subject over the course of the study. Preliminary findings of the ADAG study were disclosed at the annual meeting of the European Association for the Study of Diabetes (EASD) in Amsterdam in September 2007. Oral presentations were made at an EASD/ADA symposium and nothing has been published at the time of writing this editorial. Sixty-eight percent of the total participants had completed the study when the presentations were given. Linear regression analysis of this population reveals a good correlation between HbA1c and average blood glucose. Importantly, subgroup analysis of the population who had completed the study indicates essentially uniform findings. There is no significant difference in the regression equation between males and females, healthy controls or subjects with diabetes, individuals with type 1 or type 2 diabetes, and individuals of different ages. These results are not unexpected in light of the knowledge that glycation is a nonenzymatic process, which does not appear to be altered substantially by these factors. Nevertheless, the data are reassuring and will enable a single equation to be used for the vast majority of individuals. Importantly, the correlation fulfilled a priori criteria for acceptance. Therefore, once the study has been completed (anticipated by the end of 2007), a regression equation will be derived that will permit conversion of HbA1c results into estimated average glucose (eAG) values. What are the implications of the study? The outcome is likely to impact both patients and all health care workers, including clinicians, nurses, educators, and laboratory personnel, involved in the management of patients with diabetes. It is likely that many laboratories will use the final regression equation to calculate an eAG value based on the HbA1c result. This eAG value could be provided in addition to the measured HbA1c concentration. This would be analogous to the current reporting of the estimated glomerular filtration rate, which is derived from the measurement of serum creatinine, along with the measured creatinine value. Laboratories would report eAG in International System of Units (i.e., mmol/liter) or in milligrams per deciliter, consistent with the method of reporting glucose concentrations in that laboratory. Many clinicians believe that it will be easier to communicate eAG than HbA1c to patients. This will avoid the confusion of discussing “hemoglobin” with patients in relation to their control of blood glucose. Published studies indicate that many patients do not know whether they had a recent HbA1c measurement or its value11,12 and it is hoped that an explanation of eAG will reduce this lack of knowledge. As with most studies, ADAG suffers from some limitations. The number of Asian subjects is low (the involvement of a subgroup planned for India was not realized). Thus, the two countries with the largest numbers of patients with diabetes, namely India and China, are not represented. In addition, no children were included in the study. Although the results met a priori criteria for acceptance, the initial analysis suggests that different individuals with a particular HbA1c concentration could have somewhat different eAG. Further analysis of data might reveal the mechanism underlying this observation. For example, the magnitude of the variation in glucose concentration could contribute to this finding. Finally, an extensive (and expensive) education campaign is necessary to convey the new information to both patients with diabetes and those involved in their management. Notwithstanding these caveats, the results generated by this study will considerably enhance our comprehension of the relationship between HbA1c and average blood glucose. Data will provide, for the first time, an equation that permits accurate conversion of HbA1c values to eAG. We eagerly look forward to the final results of the study and it is hoped that the findings will lead to improved care of patients with diabetes.

Point-of-care testing of capillary glucose in the exclusion and diagnosis of diabetes in remote Australia.

Abstract: Objectives: To determine the utility of point-of-care (POC) capillary blood glucose measurements in the diagnosis and exclusion of diabetes in usual practice in primary health care in remote areas. Design: Cross-sectional study comparing POC capillary glucose results with corresponding venous glucose levels measured in a reference laboratory. Participants: 200 participants aged 16–65 years enrolled: 198 had POC capillary glucose measurements; 164 also had acceptable venous glucose laboratory results. Setting: Seven health care sites in the Kimberley region of Western Australia from May to November 2006. Main outcome measures: Concordance and mean differences between POC capillary blood glucose measurement and laboratory measurement of venous blood glucose level; POC capillary blood glucose equivalence values for excluding and diagnosing diabetes, and their sensitivity, specificity and positive-predictive value. Results: The concordance between POC and laboratory results was high (ρ = 0.93, P < 0.001). The mean difference in results was 0.48 mmol/L (95% CI, 0.23–0.73; limits of agreement, − 2.6 to 3.6 mmol/L). The POC capillary glucose equivalence values for excluding and diagnosing diabetes were < 5.5 mmol/L (sensitivity, 53.3%; specificity, 94.4%; positive-predictive value, 88.9%; for a venous value of < 5.5 mmol/L) and ≥ 12.2 mmol/L (sensitivity, 83.3%; specificity, 99.3%; positive-predictive value, 95.2%; for a venous value of ≥ 11.1 mmol/L), respectively. While the choice of glucometer and whether or not patients were fasting altered these results, they did not have a significant influence on the diagnostic utility of POC glucose measurement in this setting. Conclusion: POC capillary blood glucose analysers can be used as part of the process of diagnosing and excluding diabetes in remote rural communities using these locally established capillary equivalence values.

Glucose measurement: time for a gold standard.

Abstract: There is no internationally recognized reference method for the measurement of blood glucose. The Centers for Disease Control and Prevention (CDC) highlighted the need for standardization some years ago when a project was started. The project objectives were to (1) investigate whether there are significant differences in calibration levels among currently used glucose monitors for home use and (2) develop a reference method for glucose determination. A first study confirmed the assumption that currently used home-use monitors differ significantly and that standardization is necessary in order to minimize variability and to improve patient care. As a reference method, CDC recommended a method based on isotope dilution gas chromatography–mass spectrometry, an assay that has received support from clinical chemists worldwide. CDC initiated a preliminary study to establish the suitability of this method, but then the project came to a halt. It is hoped that CDC, with support from the industry, as well as academic and professional organizations such as the American Association for Clinical Chemistry and International Federation of Clinical Chemistry and Laboratory Medicine, will be able to finalize the project and develop the long-awaited and much needed “gold standard” for glucose measurement.

Clinical experience of an iontophoresis based glucose measuring system.

Abstract: Currently finger pricking is the common method of blood glucose measurement in patients with diabetes mellitus. However, diabetes patients have proven to be reluctant to check their glucose profiles regularly because of the discomfort associated with this technique. Recently, a non-invasive and continuous Reverse Iontophoresis based Glucose Monitoring Device (RIGMD) was developed in Korea. The study was conducted during the period November 2003-January 2004 on 19 in-patients. Glucose measurements were performed using RIGMD between 10 a.m. and 4 p.m. Concurrent plasma glucose levels were checked hourly and subsequently compared with RIGMD data. The mean error of RIGMD measurements was -3.45 +/- 52.99 mg/dL with a mean absolute relative error of 20+/-15.16%. Measurements obtained by RIGMD were correlated with plasma glucose levels (correlation coefficient; 0.784 (p<0.05)) and this correlation was independent of time of data collection. However, after excluding confounding variables this correlation coefficient exhibited a tendency to increase. 98.9% of the results were clinically acceptable by Clarke error grid analysis. We concluded that RIGMD does not have the reliability and accuracy required to wholly replace conventional methods. However, further technical advancements that reduce its shortcomings would make this device useful for the management of diabetes.

Relative risk of glucose elevation during antipsychotic exposure in a Veterans Administration population

Abstract: Concern is mounting that atypical antipsychotics cause disturbance in glucose regulation ranging from reversible hyperglycemia to diabetic ketoacidosis and death. It is difficult, however, to know what the level of risk of hyperglycemia might be for an individual patient on a particular medication of this class. We conducted a retrospective nonrandomized cohort analysis of glucose measurements in 18,764 patients receiving outpatient prescriptions for olanzapine, risperidone, or typical antipsychotics from 1 October 1998 to 30 June 2003 at six Veterans Affairs Medical Centers in the southeast United States. In patients without a random plasma glucose measurement > or =160 mg/dl before medication exposure (n=1394), treatment with index medications was associated with an incidence of new diabetes-level hyperglycemia of 78.7 cases per 1,000 individuals exposed per year. Olanzapine exposure was associated with a greater rate of developing at least one glucose measurement > or =200 mg/dl than risperidone (odds ratio=2.14, P=0.003). Olanzapine exposure was also associated with a greater rate of development of at least one fasting glucose measurement > or =126 mg/dl than risperidone. Typical antipsychotics were associated with risk intermediate between the two atypicals. These data indicate that patients with no previously observed glucose elevations develop diabetes-level hyperglycemia during antipsychotic treatment, particularly in patients receiving olanzapine.

Restoring Euglycemia in the Basal State Using Continuous Glucose Monitoring in Subjects with Type 1 Diabetes Mellitus

Abstract: Background: Our objective was to use continuous glucose monitoring to derive the optimal basal insulin infusion rates in adults with type 1 diabetes and using continuous subcutaneous insulin infusion (CSII) pumps. Methods: In an effort to mimic euglycemia during the basal state, we used a standard protocol to adjust basal insulin infusion rates in 16 subjects with type 1 diabetes mellitus who were using CSII pumps. All subjects wore Continuous Glucose Monitoring System sensors (CGMS®, Medtronic Minimed, Northridge, CA) in order to obtain around-the-clock tracings of their glucose measurements. Subjects were asked to skip meals periodically in order to optimize basal insulin infusion rates, defined as the basal infusion rates that maintained glucose levels in the range of 65–120 mg/dL during the fasting state or between meals. Results: In order to demonstrate improved glycemic control, with blunting of glucose excursion, we compared the baseline CGMS area under the curve (AUC) to the AUC obtained after opt...

Continuous subcutaneous glucose monitoring shows a close correlation between mean glucose and time spent in hyperglycemia and hemoglobin A1c.

Abstract: Background:The Diabetes Control and Complications Trial and United Kingdom Prospective Diabetes Study highlighted hemoglobin A1c (HbAlc) as the main predictor of diabetic complications. Currently, diabetes is managed by frequent capillary spot glucose measurements, but continuous monitoring systems may have the capacity of improving diabetic control. The SCGM 1 system is microdialysis based and allows for monitoring of changes in interstitial fluid glucose levels every minute. The aim of this study was to evaluate the correlation between HbAlc and short-term glucose excursions in patients with type 1 diabetes.Material and Methods:We investigated 91 patients with type 1 diabetes (mean ± standard deviation (SD); age 34 ± 10 years, body mass index 24.2 ± 4.1 kg/m2) with a duration of diabetes of 17 ± 11 years for 4.8 ± 0.4 days. The average HbA1c was 7.9 ± 1.4%. From the monitoring profiles we determined individual mean glucose, the SD of glucose, and the relative time spent in hyperglycemia and hypoglycemia...

Recent Advances in Continuous Glucose Monitoring: Biocompatibility of Glucose Sensors for Implantation in Subcutis

Abstract: Tight glycemic control slows or prevents the development of short- and long-term complications of diabetes mellitus. Continuous glucose measurements provide improved glycemic control and potentially prevent these diabetic complications. Glucose sensors, especially implantable devices, offer an alternative to classical self-monitored blood glucose levels and have shown promising glucose-sensing properties. However, the ultimate goal of implementing the glucose sensor as the glucose-sensing part of a closed loop system (artificial pancreas) is still years ahead because of malfunctions of the implanted sensor. The malfunction is partly a consequence of the subcutaneous inflammatory reaction caused by the implanted sensor. In order to improve sensor measurements and thereby close the loop, it is crucial to understand what happens at the tissue-sensor interface.

The Effect of Glucose Variability on the Risk of Microvascular Complications in Type 1 Diabetes: Response to the Diabetes Research in Children Network (DirecNet) Study Group, Service and O’Brien, and Monnier et al.

Abstract: Our analysis (1) of the Diabetes Control and Complications Trial (DCCT) dataset showed no relationship between pre- and postprandial glucose variability (SD) and the risk of microvascular complications. Wilson, on behalf of the Diabetes Research in Children Network (DirecNet) Study Group (2), makes the point that continuous glucose monitoring can detect larger postprandial glucose excursions than the single-point measurements taken in the DCCT. We agree that it would seem appropriate that future studies should employ this technique. As part of their analysis of glucose measurement in the DCCT, the article by Service and O’Brien (3) did indeed contain an analysis that found glucose variability to have the same lack of influence on retinopathy risk as ourselves, and for that they deserve credit. By specifically investigating the question of glucose variability, our article …

Comparison of two strip test methods of whole blood glucose measurement in the neonatal period.

Abstract: UNLABELLED The aim of this study was to compare the performance and accuracy of the BM Strip test used in conjunction with Reflectance photometry, and the new non-wipe strip test (Advantage) against a reference plasma glucose method. In total, 114 newborns consecutively admitted to the Neonatal Unit over a 6 mo period were enrolled into the study. Each newborn had their venous blood glucose measured by the BM Strip test and Advantage glucometer and the venous haematocrit was also determined. Plasma glucose was measured in the laboratory by the hexokinase method. The mean difference between the BM Strip test and plasma glucose was significantly less than the corresponding value for the Advantage glucometer (0.312, 95% confidence interval (CI) 0.11-0.51 vs 0.766, 95% CI 0.57-0.95], although the limits of agreement between both methods and plasma glucose were wide. Haematocrit did not influence significantly the accuracy of either test. CONCLUSION The new Advantage glucose meter does not offer any advantage over the BM Strip test. Owing to the wide limits of agreement of both methods compared with plasma glucose, their clinical value is limited in the neonatal period.

Performance analysis of a Colorimeter designed with RGB color sensor

Abstract: The ldquoGold standardrdquo for testing blood glucose in Colorimeters is the measurement of glucose in a plasma sample obtained from a vein. This method involves a chemical reaction activated by an enzyme called Glucose Oxidase. Most of the Colorimeters used for the Glucose measurement in Clinical laboratories perform well in the 100-400 mg/dL range of blood glucose. Due to the requirement of highly monochromatic source and photo detector, an error of 5 to 20% is common in these Colorimeters. This paper aims to mitigate the error in measurement by modernizing the plasma glucose testing equipment i.e., Colorimeter with White Source and RGB Color Sensor through Color measurement technique for better clinical diagnosis. As presumed, experimental results show that this modified Colorimeter can perform well with better accuracy even above the Glucose concentration of 400 mg/dL.

Ultradian Variation of Blood Glucose in Intensive Care Unit Patients Receiving Insulin Infusions

Abstract: Treatment of hyperglycemia with an insulin infusion protocol (IIP) has improved outcomes in intensive care unit (ICU) patients (1,2). While morning glucose has been reported, little is known about variation of blood glucose for patients on IIP, causing uncertainty about the optimal treatment of ICU patients (3–5). Our objectives were to test whether morning glucose represented whole-day glucose and to determine whether glucose varied over the course of the day. In ICU patients receiving IIP, glucose was lower in the early morning, correlated poorly with average glucose, and varied with an ultradian pattern. In this prospective, single-center, observational study in the ICUs of a university tertiary care hospital, we recorded all glucose measurements in two cohorts of ICU patients receiving an IIP targeting blood glucose 80–110 mg/dl. Supplementary details are available in an online appendix (available at http://dx.doi.org/10.2337/dc07-0865.). Between 20 May 2006 and 6 August 2006, 141 ICU patients were treated with IIP, 8 of whom received insulin for two periods, resulting in 149 patient episodes. The average duration of insulin use for an episode was 115 ± 9 h (range 5–604). Forty-one percent ( n = 11,670) of glucose measurements during this period were in the target range (80–110 mg/dl) (Fig. 1 A ). In preliminary data acquired between May 2004 and June 2005, the proportion of measurements in the target range increased initially and then stabilized (Fig. 1). Twenty-six percent of patients experienced at least one glucose value <60 mg/dl, and 2.7% had a glucose value <40 mg/dl. The IIP was designed to control glucose within 8 h (1), and slightly more glucose measurements beyond 8 h (42%, n = 10,766) were in range ( P = 0.014) (Fig. 1 B ). The mean and median of this positively skewed, non-Gaussian distribution ( P < 0.0001, Kolmogorov-Smirnov test) were 118.5 …

Diurnal and other variations in blood glucose in intensive care unit patients receiving insulin infusions

Abstract: Treatment of hyperglycemia in ICU patients using an insulin infusion protocol was shown by van den Berghe and colleagues to reduce mortality and morbidity in ICU patients. Consequently, many healthcare bodies proposed guidelines for the control of hyperglycemia in the ICU. However, the patchy evidence underpinning these guidelines and a high rate of complications lead to controversy about the optimal glucose target range. Studies showing insulin infusions are effective have reported average glucose values at single time points. However, single time points are difficult to interpret as they do not provide information about the proportion of glucose measurements that need to be in range for benefit. We hypothesized that blood glucose variance was greater if all glucose measurements were considered and asked whether there was a diurnal pattern that accounted for some of the variance.