Mobile phone-based self-management tools for type 2 diabetes: the few touch application

BACKGROUND

Mobile phones and other mobile information and communication technology applications and technologies hold great potential as a basis for powerful patient-operated self-management tools within diabetes. The work presented shows how such tools can be designed for supporting lifestyle changes among people with type 2 diabetes and how these were perceived by a group of 12 patients during a 6-month period.

METHOD

The study used focus groups, interviews, feasibility testing, questionnaires, paper prototyping, and prototyping of both software and hardware components. The design process was iterative, addressing the various elements several times at an increasing level of detail. The final test of the application was done qualitatively in everyday settings in a cohort of 12 people with type 2 diabetes, aged 44-70 (four men and eight women).

RESULTS

A mobile phone-based system called the Few Touch application was developed. The system includes an off-the-shelf blood glucose (BG) meter, a tailor-made step counter, and software for recording food habits and providing feedback on how users perform in relation to their own personal goals. User feedback from the 6-month user intervention demonstrated good usability of the tested system, and several of the participants adjusted their medication, food habits, and/or physical activity. Of the five different functionalities, the cohort considered the BG sensor system the best.

CONCLUSIONS

It was shown that it is possible and feasible to design an application where several sensors and feedback applications are integrated in an overall system. The presented Few Touch application challenges people with type 2 diabetes to think about how they can improve their health, providing them with a way to capture and analyze relevant personal information about their disease. The half-year user intervention demonstrated that the system had a motivational effect on the users.

Continuous glucose monitoring: real-time algorithms for calibration, filtering, and alarms

Algorithms for real-time use in continuous glucose monitors are reviewed, including calibration, filtering of noisy signals, glucose predictions for hypoglycemic and hyperglycemic alarms, compensation for capillary blood glucose to sensor time lags, and fault detection for sensor degradation and dropouts. A tutorial on Kalman filtering for real-time estimation, prediction, and lag compensation is presented and demonstrated via simulation examples. A limited number of fault detection methods for signal degradation and dropout have been published, making that an important area for future work.

Injection of Urocortin 3 into the ventromedial hypothalamus modulates feeding, blood glucose levels, and hypothalamic POMC gene expression but not the HPA axis

Urocortin 3 (Ucn 3) is a corticotropin-releasing factor (CRF)-related peptide with high affinity for the type 2 CRF receptor (CRFR2). Central administration of Ucn 3 stimulates the hypothalamic-pituitary-adrenal axis, suppresses feeding, and elevates blood glucose levels, suggesting that activation of brain CRFR2 promotes stress-like responses. Several CRFR2-expressing brain areas, including the ventromedial hypothalamus (VMH) and the posterior amygdala (PA), may be potential sites mediating the effects of Ucn 3. In the present study, Ucn 3 or vehicle was bilaterally injected into the VMH or PA, and food intake and plasma levels of ACTH, corticosterone, glucose, and insulin were determined. Food intake was greatly reduced in rats following Ucn 3 injection into the VMH. Ucn 3 injection into the VMH rapidly elevated plasma levels of glucose and insulin but did not affect ACTH and corticosterone secretion. Injection of Ucn 3 into the PA did not alter any of the parameters measured. We determined that the majority of CRFR2-positive neurons in the VMH were excitatory glutamatergic, and a subset of these neurons project to the arcuate nucleus of the hypothalamus (ARH). Importantly, stimulation of CRFR2 in the VMH increased proopiomelanocortin mRNA expression in the ARH. In conclusion, the present study demonstrates that CRFR2 in the VMH mediates some of the central effects of Ucn 3, and the ARH melanocortin system may be a downstream target of VMH CRFR2 neurons.

Methods of evaluating the utility of continuous glucose monitor alerts

BACKGROUND

The evaluation of continuous glucose monitor (CGM) alert performance should reflect patient use in real time. By evaluating alerts as real-time events, their ability to both detect and predict low and high blood glucose (BG) events can be examined.

METHOD

True alerts (TA) were defined as a CGM alert occurring within +/- 30 minutes from the beginning of a low or a high BG event. The TA time to detection was calculated as [time of CGM alert] - [beginning of event]. False alerts (FA) were defined as a BG event outside of the alert zone within +/- 30 minutes from a CGM alert. Analysis was performed comparing DexCom SEVEN PLUS CGM data to BG measured with a laboratory analyzer.

RESULTS

Of 49 low glucose events (BG < or =70 mg/dl), with the CGM alert set to 90 mg/dl, the TA rate was 91.8%. For 50% of TAs, the CGM alert preceded the event by at least 21 minutes. The FA rate was 25.0%. Similar results were found for high alerts.

CONCLUSION

Continuous glucose monitor alerts are capable of both detecting and predicting low and high BG events. The setting of alerts entails a trade-off between predictive ability and FA rate. Realistic analysis of this trade-off will guide patients in the effective utilization of CGM.

Hypoglycemia detection in critical care using continuous glucose monitors: an in silico proof of concept analysis

BACKGROUND

Tight glycemic control (TGC) in critical care has shown distinct benefits but has also been proven difficult to obtain. The risk of severe hypoglycemia (<40 mg/dl) has been increased significantly in several, but not all, studies, raising significant concerns for safety. Continuous glucose monitors (CGMs) offer frequent measurement and thus the possibility of using them for early detection alarms to prevent hypoglycemia.

METHODS

This study used retrospective clinical data from the Specialized Relative Insulin Nutrition Titration TGC study covering seven patients who experienced severe hypoglycemic events. Clinically validated metabolic system models were used to recreate a continuous blood glucose profile. In silico analysis was enabled by using a conservative single Gaussian noise model based on reported CGM clinical data from a critical care study [mean absolute percent error (MAPE) 17.4%]. A novel median filter was implemented and further smoothed with a least mean squares-fitted polynomial to reduce sensor noise. Two alarm approaches were compared. An integral-based method is presented that examined the area between a preset threshold and filtered simulated CGM data. An alarm was raised when this value became too low. A simple glycemic threshold method was also used for comparison. To account for random noise skewing the results, each patient record was Monte Carlo simulated 100 times with a different random noise profile for a total of 700 runs. Different alarm thresholds were analyzed parametrically. Results are reported in terms of detection time before the clinically measured event and any false alarms. These retrospective clinical data were used with approval from the New Zealand South Island Regional Ethics Committee.

RESULTS

The median filter reduced MAPE from 17.4% [standard deviation (SD) 13%] to 9.3% (SD 7%) over the cohort. For the integral-based alarm, median per-patient detection times ranged, t, from -35 minutes (before event) to -170 minutes, with zero to two false alarms per patient over the cohort and different alarm parameters. For a simple glycemic threshold alarm (three consecutive values below threshold), median per-patient alarm times were -10 to -75 minutes and false alarms were zero to seven; however, in one case, five of seven subjects never alarmed at all, despite the hypoglycemic event.

CONCLUSIONS

A retrospective study used clinical hypoglycemic events from a TGC study to develop and analyze an integral-based hypoglycemia alarm for use in critical care TGC studies. The integral-based approach was accurate, provided significant lead time before a hypoglycemic event, alarmed at higher glycemic levels, was robust to sensor noise, and had minimal false alarms. The approach is readily generalizable to similar scenarios, and results would justify a pilot clinical trial to verify this study.

Individuals achieve more accurate results with meters that are codeless and employ dynamic electrochemistry

BACKGROUND

Studies have shown that controlling blood glucose can reduce the onset and progression of the long-term microvascular and neuropathic complications associated with the chronic course of diabetes mellitus. Improved glycemic control can be achieved by frequent testing combined with changes in medication, exercise, and diet. Technological advancements have enabled improvements in analytical accuracy of meters, and this paper explores two such parameters to which that accuracy can be attributed.

METHODS

Four blood glucose monitoring systems (with or without dynamic electrochemistry algorithms, codeless or requiring coding prior to testing) were evaluated and compared with respect to their accuracy.

RESULTS

Altogether, 108 blood glucose values were obtained for each system from 54 study participants and compared with the reference values. The analysis depicted in the International Organization for Standardization table format indicates that the devices with dynamic electrochemistry and the codeless feature had the highest proportion of acceptable results overall (System A, 101/103). Results were significant when compared at the 10% bias level with meters that were codeless and utilized static electrochemistry (p = .017) or systems that had static electrochemistry but needed coding (p = .008).

CONCLUSIONS

Analytical performance of these blood glucose meters differed significantly depending on their technologic features. Meters that utilized dynamic electrochemistry and did not require coding were more accurate than meters that used static electrochemistry or required coding.

Antecedent caloric intake and glucose excursion following a subsequent meal in Type 1 diabetes

BACKGROUND

In the present study, we tested the hypothesis that calories consumed at a prior meal (lunch) may impair glycemic control after a subsequent meal (supper) even if the pre-supper glucose did not differ regardless of the size of the lunch meal.

METHODS

Nine subjects with Type 1 diabetes using continuous subcutaneous (s.c.) insulin infusion (CSII) therapy were studied on two separate days. Lunch (1200 h) was randomly assigned as 25% or 50% of the usual daily intake on alternate study days. The CSII was stopped at 1000 h on the day of the study and glucose was controlled until supper by adjusting the rate of intravenous (i.v.) insulin based on glucose measurements every 15 min. The CSII was restarted 1 h before supper and i.v. insulin discontinued 15 min before the first bite of supper. An identical supper meal and pre-supper s.c. bolus of short-acting insulin were administered on both visits.

RESULTS

Pre-supper glycemia was nearly identical on each of the two study days. However, the post-supper glucose area under the curve was 27.5% greater on the day of the antecedent large lunch compared with the small lunch (P = 0.0039).

CONCLUSIONS

For optimal postprandial glucose control, people with Type 1 diabetes may need to consider not only anticipated meal calories, but also prior food intake, a practice not commonly recommended based on currently used insulin dosing algorithms.

Linn)

This study examined the anti-diabetic effect of onion (Allium cepa. Linn) in the streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into normal rats fed control diet or supplemented with onion powder (7% w/w) and diabetic rats fed control diet or supplemented with onion powder. Diabetes was induced by a single injection of STZ (60 mg/kg, ip) in citrate buffer. The animals were fed each of the experimental diet for 5 weeks. Blood glucose levels of rats supplemented with onion were lower than those of rats fed control diet in the diabetic rats. Onion also decreased the total serum lipid, triglyceride, and atherogenic index and increased HDL-cholesterol/total cholesterol ratio in the diabetic rats. Glutathione peroxidase, glutathione reductase and glutathione S-transferase activities were high in the diabetic rats compared to normal rats and reverted to near-control values by onion. These results indicate that onion decreased blood glucose, serum lipid levels and reduced renal oxidative stress in STZ-induced diabetic rats and this effect might exert the anti-diabetic effect of onion.

Self-monitoring of blood glucose in noninsulin-treated type 2 diabetes: an overview

INTRODUCTION

The effectiveness of self-monitoring of blood glucose (SMBG) in noninsulin-treated patients with type 2 diabetes (T2DM) remains unclear. We aimed to review the trials investigating the effects of SMBG in this population.

METHODS

Medline was searched until June 29, 2009. Randomized controlled trials (RCTs) of at least 12 weeks' duration were included. Data on the following aspects were gathered: patient and study characteristics, effects on HbA(1c), quality of life and treatment satisfaction, and methodological quality.

RESULTS

The search revealed 9 original RCTs. These studies were very heterogeneous, and 5 were classified as of high quality. The studies with the best methodology did not show an effect of SMBG on HbA(1c), the studies with the worst methodological quality did. Two out of the 4 studies that assessed quality of life showed a significant change in favor of the control group, 1 study showed a significant change in favor of SMBG.

DISCUSSION AND CONCLUSION

We found an inverse relation between study quality and efficacy of SMBG. At this moment, there is no basis for general use of SMBG in noninsulin-treated T2DM patients.

Blood glucose controller for neonatal intensive care: virtual trials development and first clinical trials

BACKGROUND

Premature neonates often experience hyperglycemia, which has been linked to worsened outcomes. Insulin therapy can assist in controlling blood glucose (BG) levels. However, a reliable, robust control protocol is required to avoid hypoglycemia and to ensure that clinically important nutrition goals are met.

METHODS

This study presents an adaptive, model-based predictive controller designed to incorporate the unique metabolic state of the neonate. Controller performance was tested and refined in virtual trials on a 25-patient retrospective cohort. The effects of measurement frequency and BG sensor error were evaluated. A stochastic model of insulin sensitivity was used in control to provide a guaranteed maximum 4% risk of BG < 72 mg/dl to protect against hypoglycemia as well as account for patient variability over 1-3 h intervals when determining the intervention. The resulting controller is demonstrated in two 24 h clinical neonatal pilot trials at Christchurch Women's Hospital.

RESULTS

Time in the 72-126 mg/dl BG band was increased by 103-161% compared to retrospective clinical control for virtual trials of the controller, with fewer hypoglycemic measurements. Controllers were robust to BG sensor errors. The model-based controller maintained glycemia to a tight target control range and accounted for interpatient variability in patient glycemic response despite using more insulin than the retrospective case, illustrating a further measure of controller robustness. Pilot clinical trials demonstrated initial safety and efficacy of the control method.

CONCLUSIONS

A controller was developed that made optimum use of the very limited available BG measurements in the neonatal intensive care unit and provided robustness against BG sensor error and longer BG measurement intervals. It used more insulin than typical sliding scale approaches or retrospective hospital control. The potential advantages of a model-based approach demonstrated in simulation were applied to initial clinical trials.

Delays in minimally invasive continuous glucose monitoring devices: a review of current technology

Through the use of enzymatic sensors-inserted subcutaneously in the abdomen or ex vivo by means of microdialysis fluid extraction-real-time minimally invasive continuous glucose monitoring (CGM) devices estimate blood glucose by measuring a patient's interstitial fluid (ISF) glucose concentration. Signals acquired from the interstitial space are subsequently calibrated with capillary blood glucose samples, a method that has raised certain questions regarding the effects of physiological time lags and of the duration of processing delays built into these devices. The time delay between a blood glucose reading and the value displayed by a continuous glucose monitor consists of the sum of the time lag between ISF and plasma glucose, in addition to the inherent electrochemical sensor delay due to the reaction process and any front-end signal processing delays required to produce smooth traces. Presented is a review of commercially available, minimally invasive continuous glucose monitors with manufacturer reported device delays. The data acquisition process for the Medtronic MiniMed (Northridge, CA) continuous glucose monitoring system-CGMS Gold-and the Guardian RT monitor is described with associated delays incurred for each processing step. Filter responses for each algorithm are examined using in vitro hypoglycemic and hyperglycemic clamps, as well as with an analysis of fast glucose excursions from a typical meal response. Results demonstrate that the digital filters used by each algorithm do not cause adverse effects to fast physiologic glucose excursions, although nonphysiologic signal characteristics can produce greater delays.

The business of self-monitoring of blood glucose: a market profile

The market for self-monitoring of blood glucose (SMBG) approached $8.8 billion worldwide in 2008. Yet despite dramatic double-digit growth in sales of SMBG products since 1980, the business is now facing declining prices and slower dollar growth. Given that SMBG meters and test strips are viewed by consumers and insurers as essentially generic products, it will be extremely challenging for new market entrants to displace well-entrenched existing competitors without a truly innovative technology. Also, in the face of declining glucose test strip prices, market expansion can only occur through identification of more of the undiagnosed diabetes population and convincing existing diabetes patients to adopt glucose testing or to test more frequently. Ultimately, a combination of technology innovations, patient education, and economic incentives may be needed to significantly expand the SMBG market and build sustainable long-term dollar growth for SMBG vendors.

Exercise and glucose metabolism in persons with diabetes mellitus: perspectives on the role for continuous glucose monitoring

Exercise causes profound changes in glucose homeostasis. For people with type 1 diabetes, aerobic exercise usually causes blood glucose concentration to drop rapidly, while anaerobic exercise may cause it to rise, thereby making glycemic control challenging. Having the capacity to know their glucose levels and the direction of change during exercise increases self-efficacy in these persons who are prone to hypo- and hyperglycemia. For people with type 2 diabetes, learning first hand that regular exercise improves glucose levels may be a motivating factor in getting them to be more active. Continuous glucose monitoring is a potentially useful adjunct to diabetes management for the active person with either forms of diabetes. This review aims to guide the reader to use this technology to its maximum advantage by providing an overview of technical features, performance characteristics, and clinical utility, all balanced against the limitations that may be more prominent during physical activity.

Computing the risk of postprandial hypo- and hyperglycemia in type 1 diabetes mellitus considering intrapatient variability and other sources of uncertainty

OBJECTIVE

The objective of this article was to develop a methodology to quantify the risk of suffering different grades of hypo- and hyperglycemia episodes in the postprandial state.

METHODS

Interval predictions of patient postprandial glucose were performed during a 5-hour period after a meal for a set of 3315 scenarios. Uncertainty in the patient's insulin sensitivities and carbohydrate (CHO) contents of the planned meal was considered. A normalized area under the curve of the worst-case predicted glucose excursion for severe and mild hypo- and hyperglycemia glucose ranges was obtained and weighted accordingly to their importance. As a result, a comprehensive risk measure was obtained. A reference model of preprandial glucose values representing the behavior in different ranges was chosen by a xi(2) test. The relationship between the computed risk index and the probability of occurrence of events was analyzed for these reference models through 19,500 Monte Carlo simulations.

RESULTS

The obtained reference models for each preprandial glucose range were 100, 160, and 220 mg/dl. A relationship between the risk index ranges <10, 10-60, 60-120, and >120 and the probability of occurrence of mild and severe postprandial hyper- and hypoglycemia can be derived.

CONCLUSIONS

When intrapatient variability and uncertainty in the CHO content of the meal are considered, a safer prediction of possible hyper- and hypoglycemia episodes induced by the tested insulin therapy can be calculated.

Evaluation of the two-bag system for fluid management in pediatric patients with diabetic ketoacidosis

OBJECTIVES

A one-bag and a two-bag system have both been used to manage intravenous fluid administration in pediatric patients with diabetic ketoacidosis (DKA). The one-bag system, however, has been noted to have limitations, such as slow response time. This study evaluates whether the two-bag system provides any clinical benefit in pediatric DKA patients as compared to the one-bag system.

METHODS

This was a retrospective, non-blinded chart review. Inclusion criteria were patients ≤ 18 years old and whose admission had the code of DKA as the diagnosis. Baseline clinical and demographic data were collected. Descriptive statistics were used in the data analysis.

RESULTS

A total of 31 patients were included, 9 (29%) in the one-bag group and 22 (71%) in the two-bag group. Baseline characteristics were similar between the two groups. Mean (SD) rate of complete blood glucose (CBG) correction was 31.04 mg/dL/hr (20.61) in the two-bag group and 21.04 mg/dL/hr (16.26) in the one-bag group (p = 0.297). The rate of bicarbonate correction, however, was faster with the two-bag system than the one-bag system (0.949 ± 0.553 mEq/L/hr and 0.606 ± 0.297 mEq/L/hr, respectively) (p = 0.047). The two-bag system also had a faster time to ketone (p = 0.04), but not pH (p = 0.172), correction.

CONCLUSIONS

The two-bag system provided a faster rate of bicarbonate and ketone correction compared to the one-bag system. The two-bag system also provided a trend towards a faster rate of blood glucose and pH correction.

Applying the Taguchi design for optimized formulation of sustained release gliclazide chitosan beads: an in vitro/in vivo study

Gliclazide is a second generation of hypoglycemic sulfonylurea and acts selectively on pancreatic beta cell to control diabetes mellitus. The objective of this study was to produce a controlled release system of gliclazide using chitosan beads. Chitosan beads were produced by dispersion technique using tripolyphosphate (TPP) as gelating agent. The effects of process variables including chitosan molecular weight, concentration of chitosan and TPP, pH of TPP, and cross-linking time after addition of chitosan were evaluated by Taguchi design on the rate of drug release, mean release time (MRT), release efficiency (RE(8)%), and particle size of the beads. The blood glucose lowering effect of the beads was studied in normal and streptozotocin-diabetic rats. The optimized formulation CL(2)T(5)P(2)t(10) with about 31% drug loading, 2.4 h MRT, and 69.16% RE(8)% decreased blood glucose level in normal rats for 24 h compared to pure powder of gliclazide that lasted for just 10 h.

Protective effect of Cassia glauca Linn. on the serum glucose and hepatic enzymes level in streptozotocin induced NIDDM in rats

OBJECTIVE

The objective of the present study was to investigate the hypoglycemic and hepatoprotective effect of Cassia glauca leaf extracts on normal and non insulin dependent diabetes mellitus (NIDDM) in rats. The study was further carried out to investigate the effect of different fractions of the active extract of Cassia glauca, on normal and NIDDM rats, and the effect of active fraction on the blood glucose and hepatic enzymes level.

METHODS

Diabetes was induced by streptozotocin (STZ) at a dose of 90mg/kg, i.p. in neonates. Different extracts of cassia glauca (100mg/kg, p.o.) were administered to the diabetic rats. Acetone extract was found to lower the serum glucose level significantly in diabetic rats. Further, the acetone extract was subjected to column chromatography and four fractions were obtained on the basis of TLC. All the four fractions (100mg/kg, p.o.) were administered to the diabetic rats. Fraction 1 (F1) caused the maximum reduction in the blood glucose level. The results of the test were compared with the standard antidiabetic drug glibenclamide (5mg/kg, p.o.).

RESULTS

Fraction 1 of acetone extract caused a significant reduction in the levels of hepatic enzyme Aspartate transaminase (AST), alanine transaminase (ALT), creatine kinase (CK), and lactate dehydrogenase (LDH) in STZ-induced diabetic rats.

CONCLUSION

Improvement in the blood sugar level and normalization of liver functions by Cassia glauca indicates that the plant has hepatoprotective potential, along with antidiabetic activity, and it provides a scientific rationale for the use of Cassia glauca as an antidiabetic agent.

Joint analysis of individual participants' data from 17 studies on the association of the IL6 variant -174G>C with circulating glucose levels, interleukin-6 levels, and body mass index

BACKGROUND

Several studies have investigated associations between the -174G>C single nucleotide polymorphism (rs1800795) of the IL6 gene and phenotypes related to type 2 diabetes mellitus (T2DM) but presented inconsistent results.

AIMS

This joint analysis aimed to clarify whether IL6 -174G>C was associated with glucose and circulating interleukin-6 concentrations as well as body mass index (BMI).

METHODS

Individual-level data from all studies of the IL6-T2DM consortium on Caucasian subjects with available BMI were collected. As study-specific estimates did not show heterogeneity (P>0.1), they were combined by using the inverse-variance fixed-effect model.

RESULTS

The main analysis included 9440, 7398, 24,117, or 5659 non-diabetic and manifest T2DM subjects for fasting glucose, 2-hour glucose, BMI, or circulating interleukin-6 levels, respectively. IL6 -174 C-allele carriers had significantly lower fasting glucose (-0.091 mmol/L, P=0.014). There was no evidence for association between IL6 -174G>C and BMI or interleukin-6 levels, except in some subgroups.

CONCLUSIONS

Our data suggest that C-allele carriers of the IL6 -174G>C polymorphism have lower fasting glucose levels on average, which substantiates previous findings of decreased T2DM risk of these subjects.

The Association between Concentrations of Green Tea and Blood Glucose Levels

Our objective was to examine whether habitual green tea consumption is associated with blood glucose levels and other biomarkers of glucose metabolism. We conducted a cross-sectional study of 35 male volunteers, 23–63 years old and residing in Shizuoka Prefecture in Japan. Biochemical data were measured and we conducted a questionnaire survey on health, lifestyle, and nutrition, as well as frequency of consumption and concentrations (1%, 2%, and 3%) of green tea. Men who consumed a 3% concentration of green tea showed lower mean values of fasting blood glucose and fructosamine than those who consumed a 1% concentration. Fasting blood glucose levels were found to be significantly associated with green tea concentration (β = −0.14, p = 0.03). However, green tea consumption frequency showed no significant differences in mean levels of blood glucose, fructosamine and hemoglobin A_1c. In conclusion, our findings suggest that the consumption of green tea at a high concentration has the potential to reduce blood glucose levels.

[Early determinants of random blood glucose among adults of the 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To evaluate the effects of socioeconomic variables, birth weight, duration of breastfeeding and income changes on random blood glucose levels among young adults.

METHODS

This was a study on the birth cohort from 1982, when the 5,914 hospital births that occurred in the city of Pelotas (Southern Brazil) were identified and the mothers were interviewed. The children whose families lived in the urban area of the city were followed up several times. In 2004-5, 4,927 individuals of the cohort were interviewed and blood was collected from the fingertips of 3,730 of them for random blood glucose measurements. Associations between random blood glucose levels and skin color, family income at birth, maternal schooling, income change between 1982 and 2004-5, birth weight and duration of breastfeeding were evaluated.

RESULTS

The mean blood glucose level was 97.3 +/- 15.1mg/dL, and it was greater among the men. None of the variables studied was associated with the men's blood glucose level. Among the women, maternal schooling, family income at 23 years of age and birth weight were inversely associated with blood glucose levels. However, birth weight lost its statistical significance in the multivariable analysis.

CONCLUSIONS

Birth weight and duration of breastfeeding did not present any long-term effect on random blood glucose levels. Only maternal schooling level and present income presented associations with random blood glucose levels among the women.

The benefits of continuous glucose monitoring and a glucose monitoring schedule in individuals with type 1 diabetes during recreational diving

BACKGROUND

Our objective is to evaluate the Medtronic CGMS continuous glucose monitoring system and plasma glucose (PG) measurement performed in a monitoring schedule as tools to identify individuals with type 1 diabetes at risk when diving.

METHODS

We studied 24 adults, 12 type 1 diabetes subjects and 12 controls, during 5 recreational scuba dives performed on 3 consecutive days. The CGMS was used by all participants on all the days and all the dives. Comparisons were made between PG performed in a monitoring schedule during the days of diving, self-monitored blood glucose (SMBG) performed 2 weeks prior to diving, and the CGMS during the study.

RESULTS

One hundred seventeen dives were performed. Hypoglycemia (<70 mg/dl) was found in six individuals and on nine occasions. However, no symptoms of hypoglycemia were present during or immediately postdiving. In one case, repetitive hypoglycemia prediving gave rise to a decision not to dive. None of the dives were aborted. The number of hypoglycemic episodes, 10 min prediving or immediately postdiving, were related to the duration of diabetes, r = 0.83 and p =0.01, and the percentage of SMBG values below target (<72 mg/dl), r = 0.65 and p =0.02. Moreover, the number of hypoglycemic episodes was also related to the total duration below low limit (<70 mg/dl), measured by the CGMS, r =0.74 and p =0.006.

CONCLUSION

Safe dives are possible to achieve by well-informed, well-controlled individuals with type 1 diabetes. Using downloaded SMBG, CGMS, and repetitive PG in a monitoring schedule, it is possible to identify those subjects who are suitable for diving.

A subcutaneous insulin pharmacokinetic model for computer simulation in a diabetes decision support role: validation and simulation

OBJECTIVE

The goal of this study was to validate a previously derived and identified physiological subcutaneous (SC) insulin absorption model for computer simulation in a clinical diabetes decision support role using published pharmacokinetic summary measures.

METHODS

Validation was performed using maximal plasma insulin concentration (C(max)) and time to maximal concentration (t(max) pharmacokinetic summary measures. Values were either reported or estimated from 37 pharmacokinetic studies over six modeled insulin types. A validation comparison was made to equivalent pharmacokinetic summary measures calculated from model generated curves fitted to respective plasma insulin concentration data. The validation result was a measure of goodness of fit. Validation for each reported study was classified into one of four cases.

RESULTS

Of 37 model fits, 22 were validated on both the C(max) and the t(max) summary measures. Another 6 model fits were partially validated on one measure only due to lack of reporting on the second measure with errors to reported or estimated ranges of <12%. Another 7 studies could not be validated on either measure because of inadequate reported clinical data. Finally, 2 separate model fits to data from the same study failed the validation with 90 and 71% error on t(max) only, which was likely caused by protocol-based error. No model fit failed the validation on both measures.

CONCLUSIONS

A previously derived and identified model was clinically validated for six insulin types using C(max) and t(max) summary measures from published pharmacokinetic studies. Hence, this article presents a clinically valid model that accounts for multiple nonlinear effects and six different types of SC insulin in a computationally modest form suitable for use in clinical decision support.

A subcutaneous insulin pharmacokinetic model for computer simulation in a diabetes decision support role: model structure and parameter identification

OBJECTIVE

The goal of this study was to develop a unified physiological subcutaneous (SC) insulin absorption model for computer simulation in a clinical diabetes decision support role. The model must model the plasma insulin appearance of a wide range of current insulins, especially monomer insulin and insulin glargine, utilizing common chemical states and transport rates, where appropriate.

METHODS

A compartmental model was developed with 13 patient-specific model parameters covering six diverse insulin types [rapid-acting, regular, neutral protamine Hagedorn (NPH), lente, ultralente, and glargine insulin]. Model parameters were identified using 37 sets of mean plasma insulin time-course data from an extensive literature review via nonlinear optimization methods.

RESULTS

All fitted parameters have a coefficient of variation <100% (median 51.3%, 95th percentile 3.6-60.6%) and can be considered a posteriori identifiable.

CONCLUSION

A model is presented to describe SC injected insulin appearance in plasma in a diabetes decision support role. Clinically current insulin types (monomeric insulin, regular insulin, NPH, insulin, and glargine) and older insulin types (lente and ultralente) are included in a unified framework that accounts for nonlinear concentration and dose dependency. Future work requires clinical validation using published pharmacokinetic studies.

Miscoding and other user errors: importance of ongoing education for proper blood glucose monitoring procedures

BACKGROUND

This article reviews the literature to date and reports on a new study that documented the frequency of manual code-requiring blood glucose (BG) meters that were miscoded at the time of the patient's initial appointment in a hospital-based outpatient diabetes education program.

METHOD

Between January 1 and May 31, 2007, the type of BG meter and the accuracy of the patient's meter code (if required) and procedure for checking BG were checked during the initial appointment with the outpatient diabetes educator. If indicated, reeducation regarding the procedure for the BG meter code entry and/or BG test was provided.

RESULTS

Of the 65 patients who brought their meter requiring manual entry of a code number or code chip to the initial appointment, 16 (25%) were miscoded at the time of the appointment. Two additional problems, one of dead batteries and one of improperly stored test strips, were identified and corrected at the first appointment.

CONCLUSIONS

These findings underscore the importance of checking the patient's BG meter code (if required) and procedure for testing BG at each encounter with a health care professional or providing the patient with a meter that does not require manual entry of a code number or chip to match the container of test strips (i.e., an autocode meter).

Tight glycemic control in the hospital

Single center randomized controlled trials could demonstrate a benefit of strict glycemic control on the mortality and morbidity outcomes for critically ill patients. Although observational studies also demonstrate a benefit of tight glucose control for patients in general wards, direct evidence is still lacking. Overall, the implementation of glucose control both in the very controlled setting of an intensive care unit and even more so in the clearly less controlled setting of a general ward has proven to be difficult. Standardization of all required working steps to establish glycemic control needs to be considered to be able to achieve safe and good blood glucose control. Recent developments from diabetes technology will have an important impact in facilitating glucose control in the hospital, although the already established workflows in hospitals will require a substantial reconsideration of diabetes-oriented technology to allow an area-wide implementation and acceptance by health care personnel.

Post-challenge blood glucose concentration and stroke mortality rates in non-diabetic men in London: 38-year follow-up of the original Whitehall prospective cohort study

AIMS/HYPOTHESIS

While individuals with diabetes have a raised risk of stroke, it is unclear whether hyperglycaemia in non-diabetic populations is related to the development of this disease.

METHODS

In this prospective cohort study of 19,019 men, capillary blood was drawn 2 h after consumption of a glucose preparation equivalent to 50 g of anhydrous dextrose. Study participants were then followed for mortality for a maximum of 38 years.

RESULTS

During follow-up of 18,406 non-diabetic men, 13,116 deaths occurred (1,189 by stroke). Plots of stroke mortality rates versus blood glucose identified an upward inflection in risk of death from stroke at about 4.6 mmol/l. This upward inflection in risk could be adequately described using a single linear term above this threshold. A 1 mmol/l increase in blood glucose after this point was associated with a 27% increase in risk of death from stroke (hazard ratio 1.27, 95% CI 1.14-1.42). This increase in risk was partially attenuated by adjustment for covariates (1.17, 1.04-1.31) but remained statistically significant at conventional levels. Similar observations were made when all-cause mortality was the outcome of interest, although the magnitude of the association with blood glucose was somewhat lower.

CONCLUSIONS/INTERPRETATION

An incremental elevation in stroke mortality rates occurs with increasing post-challenge blood glucose.

Use of a computerized intravenous insulin algorithm within a nurse-directed protocol for patients undergoing cardiovascular surgery

BACKGROUND

Several studies have shown the benefits of tight glycemic control in the intensive care unit. A large hospital became concerned about certain deficiencies in the management of glucose control in conjunction with cardiovascular surgery. A multidisciplinary steering committee was formed, which implemented a glycemic protocol, the subject of this study.

METHODS

The glycemic protocol is a perioperative, nurse-directed program that incorporates the computerized intravenous (IV) insulin algorithm, Glucommander. Upon admission, hemoglobin A1c and blood glucose (BG) were tested, and patients were screened for previously diagnosed diabetes. This information was used to determine if preoperative insulin will be used, if the patient will be transitioned post-IV to subcutaneous (SC) basal-bolus insulin, and if insulin will be prescribed on discharge. IV insulin was initiated perioperatively in known diabetes cases or if one BG value >140 mg/dl or two BG values >110 mg/dl within 24 hours before or during surgery. The target range was 90 to 120 mg/dl.

RESULTS

In the 9 months after protocol implementation, 93% of the patients had no BG value >200 mg/dl during the first 48 hours postoperatively. In the 6 months of study data, there were 457 patients. The mean time to target range was 3.0 hours. The mean IV insulin run time was 37 hours. The mean BG value was 107 mg/dl. Only 2% of patients had transient BG <50 mg/dl, and no BG values were <40 mg/dl. Of the patients, 52% were transitioned to SC basal-bolus, and 26% were discharged on insulin.

CONCLUSIONS

The Glucommander earned high respect from the nurses for the way it scheduled BG tests and eliminated the calculation time and calculation errors associated with manual methods. The protocol was highly effective in normalizing glucose without hypoglycemia. The multidisciplinary steering committee proved to be a good approach to implementing a glycemic protocol.

Development of a clinical type 1 diabetes metabolic system model and in silico simulation tool

OBJECTIVES

The goal of this study was to develop a system model of type 1 diabetes for the purpose of in silico simulation for the prediction of long-term glycemic control outcomes.

METHODS

The system model was created and identified on a physiological cohort of virtual type 1 diabetes patients (n = 40). Integral-based identification was used to develop (n = 40) insulin sensitivity profiles.

RESULTS

The n = 40 insulin sensitivity profiles provide a driving input for virtual patient trials using the models developed. The identified models have a median (90% range) absolute percentage error of 1.33% (0.08-7.20%). The median (90% range) absolute error was 0.12 mmol/liter (0.01-0.56 mmol/liter). The model and integral-based identification of SI captured all patient dynamics with low error, which would lead to more physiological behavior simulation.

CONCLUSIONS

A simulation tool incorporating n = 40 virtual patient data sets to predict long-term glycemic control outcomes from clinical interventions was developed based on a physiological type 1 diabetes metabolic system model. The overall goal is to utilize this model and insulin sensitivity profiles to develop and optimize self-monitoring blood glucose and multiple daily injection therapy.

Model-based insulin sensitivity as a sepsis diagnostic in critical care

BACKGROUND

Timely diagnosis and treatment of sepsis in critical care require significant clinical effort, experience, and resources. Insulin sensitivity is known to decrease with worsening condition and could thus be used to aid diagnosis. Some glycemic control protocols are able to identify insulin sensitivity in real time.

METHODS

Receiver operating characteristic curves and cutoff insulin sensitivity values for diagnosing sepsis were calculated for model-based insulin sensitivity (S(I)) and a simpler metric (SS(I)) that was estimated from glycemic control data of 30 patients with sepsis and can be calculated in real time without use of a computer. Results were compared to the insulin sensitivity profiles of a general intensive care unit population of 113 patients without sepsis and 30 patients with sepsis, comprising a total of 26,453 patient hours. Patients with sepsis were identified as having sepsis based on a sepsis score (ss) of 3 or higher (ss = 0 - 4 for increasing severity). Patients with type I or type II diabetes were excluded. Ethics approval for this study was granted by the South Island Regional Ethics Committee.

RESULTS

Receiver operating characteristic cutoff values of S(I) = 8 x 10-5 liter mU(-1) min(-1) and SS(I) = 2.8 x 10-4 liter mU(-1) min(-1) were determined for ss > or = 3. The model-based S(I) fell below this value in 15% of all patient hours. The S(I) test had a negative predictive value of 99.8%. The test sensitivity was 78% and specificity was 82%. However, the positive predictor value was 2.8%. Slightly lower sensitivity (68.8%) and specificity (81.7%), but equally good negative prediction (99.7%), were obtained for the estimated SS(I).

CONCLUSIONS

Insulin sensitivity provides a negative predictive diagnostic for sepsis. High insulin sensitivity rules out sepsis for the majority of patient hours and may be determined noninvasively in real time from glycemic control protocol data. Low insulin sensitivity is not an effective diagnostic, as it can equally mark the presence of sepsis or other conditions.

In silico simulation of long-term type 1 diabetes glycemic control treatment outcomes

OBJECTIVES

The goals of this study were to develop (1) a safe and effective protocol for the clinical control of type 1 diabetes using conventional self-monitoring blood glucose (SMBG) measurements and multiple daily injections with insulin analogues, and (2) an in silico simulation tool of type 1 diabetes to predict long-term glycemic control outcomes of clinical interventions.

METHODS

The virtual patient method was used to develop a simulation tool for type 1 diabetes using data from a type 1 diabetes patient cohort (n = 40). The tool was used to test the adaptive protocol (AC) and a conventional intensive insulin therapy (CC) against results from a representative control cohort. Optimal and suboptimal basal insulin replacements were evaluated as a function of SMBG frequency in conjunction with the (AC and CC) prandial control protocols.

RESULTS

In long-term glycemic control, the AC protocol significantly decreased hemoglobin A1c in conditions of suboptimal basal insulin replacement for SMBG frequencies > or = 6/day, and reduced the occurrence of mild and severe hypoglycemia by 86-100% over controls, over all SMBG frequencies in conditions of optimal basal insulin.

CONCLUSIONS

A simulation tool to predict long-term glycemic control outcomes from clinical interventions has been developed to test a novel, adaptive control protocol for type 1 diabetes. The protocol is effective and safe compared to conventional intensive insulin therapy and controls. As fear of hypoglycemia is a large psychological barrier to glycemic control, the AC protocol may represent the next evolution of intensive insulin therapy to deliver increased glycemic control with increased safety. Further clinical or experimental validation is needed to fully prove the concept.

Improvement in glycemic control and outcome corresponding to intensive insulin therapy protocol development

BACKGROUND

Intensive insulin therapy (IIT) has been shown to reduce mortality and morbidity in longer stay, critically ill patients. However, this has been demonstrated in a single site, whereas two multicentric studies have been terminated prematurely mainly due to hypoglycemia. Other difficulties with IIT include efficacy of glycemic control. This report describes how IIT can be improved by protocol simplification and removal of glucose supplementation.

METHODS

A clinical information system established at each bedspace guided staff through the IIT algorithms. Time spent within predefined glycemic ranges was calculated assuming a linear trend between successive measurements. Three groups were investigated retrospectively: IIT1 protocol,(1) an updated IIT2 version, and intuitive nurse dosing of conventional insulin therapy (CIT).

RESULTS

Fifty consecutive, critically ill patients were included in each study group. Patient characteristics were similar in each group. The frequency of CIT and IIT2 blood glucose measurements were 11.6 and 11.5 measurements per day, respectively, while the IIT1 measurements were more frequent (14.5 measurements per day). The mean proportion of time spent in the target glycemic range (4.4-6.1 mmol/liter) was highest in the IIT2 group (34.9%), as compared to the IIT1 (22.9%) and CIT groups (20.3%) (p <.001). Survival at 28 days was 74.5% for IIT2 (highest), 68% for IIT1, and 48% for CIT (p = .02). There were a similar number of those experiencing a severe hypoglycemic event in each group.

CONCLUSIONS

IIT protocol optimization was associated with increased glycemic control and improved 28-day survival. The better optimized IIT2 protocol provided tighter control than either the IIT1 or CIT protocol, without increased sampling or incidence of hypoglycemia. The clinical effectiveness of the IIT algorithm appeared to be improved by simplifying the protocol to meet the needs of the critical care unit.

Optimum subcutaneous glucose sampling and fourier analysis of continuous glucose monitors

BACKGROUND

The objective of this article was to focus on the application of harmonic decomposition to continuous glucose monitor (CGM) measurements. We show evidence of an attenuation of fast variations of interstitial glucose when compared to blood in type 1 diabetes mellitus (T1DM) and, using information theory, propose optimal sampling schedules associated with the use and study of CGMs.

METHOD

Using a cohort of 26 T1DM subjects, wearing two Navigator sensors for 1 to 3 days, we analyzed the frequency content of each glucose signal and derived across subject frequency cutoffs using discrete Fourier transform and common signal processing techniques.

RESULTS

We observed a significant difference in the frequency content of blood glucose compared to interstitial glucose in T1DM, providing evidence toward the existence of a diffusion process between blood and interstitial glucose, acting as a low-pass filter. Furthermore, we obtained a 15-minutes sampling schedule for optimal comparison of CGM values to blood reference.

CONCLUSION

Blood glucose and interstitial glucose have different dynamics, as shown by harmonic analysis, and these differences have consequences on advisable schedules for accuracy studies of CGMS.

Effects of clozapine administration on body weight, glucose tolerance, blood glucose concentrations, plasma lipids, and insulin in male C57BL/6 mice: A parallel controlled study

BACKGROUND

Clozapine has been associated with metabolic adverse events (AEs) (eg, elevated body weight, blood glucose concentrations, cholesterol, triglycerides [TG]), all of which have deleterious effects on health and medication compliance. However, little focus has been directed toward finding a suitable experimental model to study the metabolic AEs associated with clozapine.

OBJECTIVE

The aim of this study was to assess the effects of clozapine administration for 28 days on body weight, glucose tolerance, blood glucose concentrations, plasma lipids, and insulin in C57BL/6 mice.

METHODS

C57BL/6 mice were grouped and treated with clozapine 2 or 10 mg/kg or vehicle intraperitoneally QD for 28 days. Body weight was assessed on days 0 (baseline), 7, 14, 21, and 28, and glucose tolerance, blood glucose concentrations, insulin (calculated by insulin resistance index [IRI]), and plasma lipids (including total cholesterol, TG, high-density lipoprotein cholesterol [HDL-C], and low-density lipoprotein cholesterol) were assessed on day 29.

RESULTS

Sixty 10-week-old, male C57BL/6 mice were included in the study and were divided into 3 groups (20 mice per group). The body weight significantly decreased in the clozapine 10-mg-treated group on days 14, 21, and 28 compared with the vehicle group (mean [SD] body weight: 21.61 [1.05] vs 22.79 [1.11], 22.53 [1.05] vs 24.17 [1.24], and 22.21 [1.07] vs 24.99 [1.39] g, respectively; all, P < 0.05). In the clozapine 10-mg/kg group, blood glucose concentrations significantly increased 0, 30, 60, and 120 minutes after glucose administration compared with the vehicle group (mean [SD]: 6.67 [1.25], 25.34 [5.85], 12.68 [3.39], and 7.52 [1.45] mmol/L, respectively, vs 4.61 [0.78], 21.54 [6.55], 11.46 [3.46], and 6.55 [1.42] mmol/L, respectively; all P < 0.05). The clozapine 10-mg/kg group also had significant increases in plasma insulin concentrations compared with the vehicle group (12.70 [5.27] vs 7.62 [4.54] μIU/mL; P < 0.05) and IRI (3.01 [1.26] vs 1.51 [0.96]; P < 0.05). Plasma HDL-C concentration also significantly decreased in the clozapine 10-mg/kg group compared with the vehicle group (1.23 [0.25] vs 1.47 [0.16]; P < 0.05).

CONCLUSION

Clozapine 10 mg/kg was associated with significant decreases in body weight and significant increases in fasting blood glucose and glucose tolerance in these male C57BL/6 mice.

Use of the DirecNet Applied Treatment Algorithm (DATA) for diabetes management with a real-time continuous glucose monitor (the FreeStyle Navigator)

BACKGROUND

There are no published guidelines for use of real-time continuous glucose monitoring data by a patient; we therefore developed the DirecNet Applied Treatment Algorithm (DATA). The DATA provides algorithms for making diabetes management decisions using glucose values: (i) in real time which include the direction and rate of change of glucose levels, and (ii) retrospectively based on downloaded sensor data.

OBJECTIVE

To evaluate the use and effectiveness of the DATA in children with diabetes using a real-time continuous glucose sensor (the FreeStyle Navigator).

SUBJECTS

Thirty children and adolescents (mean +/- standard deviation age = 11.2 +/- 4.1 yr) receiving insulin pump therapy.

METHODS

Subjects were instructed on use of the DATA and were asked to download their Navigator weekly to review glucose patterns. An Algorithm Satisfaction Questionnaire was completed at 3, 7, and 13 wk.

RESULTS

At 13 wk, all of the subjects and all but one parent thought that the DATA gave good, clear directions for insulin dosing, and thought the guidelines improved their postprandial glucose levels. In responding to alarms, 86% of patients used the DATA at least 50% of the time at 3 wk, and 59% reported doing so at 13 wk. Similar results were seen in using the DATA to adjust premeal bolus doses of insulin.

CONCLUSIONS

These results show the feasibility of implementing the DATA when real-time continuous glucose monitoring is initiated and support its use in future clinical trials of real-time continuous glucose monitoring.

Treatment intensification and blood glucose control among hospitalized diabetic patients

BACKGROUND

Hyperglycemia is common among diabetic inpatients, and has been linked to adverse outcomes. However, antihyperglycemic treatment is seldom intensified in noncritical care patients, and the relationship between intensification frequency and glucose control is poorly understood. We evaluated the relationship between treatment intensification and changes in blood glucose in hospitalized diabetic patients.

DESIGN

We retrospectively analyzed 3,613 hospitalized diabetic patients who were admitted to the hospital between January 2003 and August 2004, were not hospitalized in an ICU, were not prescribed IV insulin or total parenteral nutrition (TPN), had a length of stay of at least 3 days, and had at least one point-of-care blood glucose measurement. A linear model was used to assess the relationship between intensification of antihyperglycemic medications and the average daily change in point-of-care glucose measurements.

RESULTS

Hyperglycemia (>180 mg/dL) was documented at least once for 82.5% of patient admissions. Antihyperglycemic treatment was intensified for 22.0% of days with hyperglycemia. Intensifications of scheduled and sliding scale insulin, but not oral medications, were associated with a 11.1 mg/dL (p < 0.0001) and 12.2 mg/dL (p < 0.0001) reduction in the average daily glucose, respectively. Hypoglycemia (<50 mg/dL) was documented on 2.2% of days after antihyperglycemic treatment intensification.

CONCLUSION

In this cohort, lack of treatment intensification in response to inpatient hyperglycemia was common. Antihyperglycemic treatment intensification was strongly associated with decrease in average daily glucose, while hypoglycemia was uncommon. This suggests that increasing the frequency of treatment intensifications could lead to improved glycemic control in inpatients with diabetes.

Inhaled insulin for controlling blood glucose in patients with diabetes

Diabetes mellitus is a significant worldwide health problem, with the incidence of type 2 diabetes increasing at alarming rates. Insulin resistance and dysregulated blood glucose control are established risk factors for microvascular complications and cardiovascular disease. Despite the recognition of diabetes as a major health issue and the availability of a growing number of medications designed to counteract its detrimental effects, real and perceived barriers remain that prevent patients from achieving optimal blood glucose control. The development and utilization of inhaled insulin as a novel insulin delivery system may positively influence patient treatment adherence and optimal glycemic control, potentially leading to a reduction in cardiovascular complications in patients with diabetes.

A cause-and-effect-based mathematical curvilinear model that predicts the effects of self-monitoring of blood glucose frequency on hemoglobin A1c and is suitable for statistical correlations

BACKGROUND

Previous studies have shown an association between the frequency of self-monitored blood glucose (SMBG) and hemoglobin A1c. Randomized controlled trials (RCTs) have shown this to be a causal correlation for insulin-using patients. Several studies have used linear regression, but a straight line will descend into negative hemoglobin A1c values (an impossibility). This study developed a cause-and-effect-based nonlinear model to predict the outcome of RCTs on this subject, tested this model with clinical data, and offered this model in place of linear regression, especially for the still-debated case of noninsulin-using patients.

METHODS

The model was developed from cause-and-effect principles. The clinical study utilized retrospective data from patient histories of a large endocrine practice. Data sets were obtained for five treatment regimens: continuous subcutaneous insulin infusion (CSII), subcutaneous insulin (SC), no insulin (NI), oral medication (OM), and no medication (NM). OM and NM are subgroups of NI. The model was fitted to each group using nonlinear leastsquares methods. Each group was ordered by SMBG tests per day (BGpd) and was divided in half; t tests were run between the A1C's of the two halves.

RESULTS

Self-monitored blood glucose readings from 1255 subjects were analyzed (CSII, N = 417; SC, N = 286; NI, N = 552; OM, N = 505; NM, N = 47). The CSII, SC, NI, and OM groups showed the expected declining statistically fitted curve and a significant association of BGpd with hemoglobin A1c (P < 0.004). The NM group showed insignificant results.

CONCLUSIONS

The nonlinear model is based on cause-and-effect principles and mathematics. It yields a prediction that RCTs will be able to reveal that higher SMBG frequency causes lower hemoglobin A1c.

Randomized studies are needed to assess the true role of self-monitoring of blood glucose in noninsulin-treated type 2 diabetes

Numerous trials have been conducted to assess the utility of self-monitoring of blood glucose (SMBG) in noninsulin-treated type 2 diabetic (T2DM) patients. Although recent meta-analyses support the benefits of SMBG, the clinical utility of SMBG in this population remains controversial due to a lack of large, randomized controlled trials. Much of the skepticism regarding SMBG in noninsulin-treated T2DM may stem from a misapplication or misunderstanding of the true role of SMBG. The benefits of SMBG are realized only when both the patient and the health care provider (HCP) know how and are willing to monitor, interpret, and respond appropriately to acute glucose excursions and patterns of glycemia identified through SMBG. Optimal utilization of SMBG requires that patients be trained and motivated to accurately perform SMBG at the time and frequency prescribed, accurately interpret the data they obtain, act upon the information when appropriate, and consistently document results for later review with their HCP. HCPS must be willing and able to routinely monitor SMBG data and make appropriate adjustments in therapy. Numerous studies are needed to evaluate the true value and utility of SMBG within the diverse T2DM population to ensure that resources for diabetes management can be used efficiently. This article identifies and discusses key factors to consider for the design of randomized studies that can provide a foundation upon which HCPs and health care systems may reevaluate their current strategies/protocols and incorporate the learnings into more effective approaches to patient care.

Cardiovascular risk factor levels and their relationships with overweight and fat distribution in children: the Fleurbaix Laventie Ville Santé II study

This study aimed to document for the first time in a general population of French children the prevalence and levels of cardiovascular risk factors and to assess separately in boys and girls whether these risk factors were associated with fat mass distribution independently of subcutaneous overall adiposity. A cross-sectional analysis of baseline data from 452 children (235 boys and 217 girls) aged 8 to 17 years included in a 1999 population-based epidemiologic study (the Fleurbaix Laventie Ville Santé II study) was made. Overweight was defined according to the International Obesity Task Force references and the 90th percentiles of the French body mass index curves. The thresholds of parameters defining cardiovascular and metabolic risks were the 95th percentile of the Task Force Report on High Blood Pressure in Children and Adolescents for blood pressure and those of the American Academy of Pediatrics for lipids. Anthropometric and biological parameters were described by sex and according to overweight status. Partial correlations between cardiovascular risk factors and anthropometric measures of adiposity (body mass index, sum of 4 skinfold thicknesses, waist circumference, waist-to-height ratio) were calculated. Then, these correlations were additionally adjusted for the sum of 4 skinfold thicknesses. High plasma triglycerides, high insulin concentration, and low plasma high-density lipoprotein cholesterol (HDL-C) concentration were associated with all measures of adiposity (|r| > or = 0.20, P < .002). When obese children were excluded, overweight children already had high triglycerides and low HDL-C levels, respectively, 2 and 20 times more frequently than normal-weight children did. Among overweight children, 7.7% had at least 2 risk factors among high blood pressure, high plasma triglycerides or glucose, and low HDL-C concentration vs 0.25% among normal-weight children (P = .002). After adjusting for the sum of skinfolds, an independent association between the risk factors and waist circumference was found in girls. In conclusion, (a) modest excess weight is associated with increased levels of cardiovascular risk factors. (b) In girls, abdominal fat distribution is associated with cardiovascular risk factors, independently of overall adiposity. (c) International definition of abdominal obesity in children is required to standardize studies and to progress in the evaluation of childhood obesity and its consequences.

Measurement quality of blood glucose meters: is there a need for an institution with an unbiased view?

The quality of self-monitoring of blood glucose (SMBG) with modern blood glucose meters is considered by many as not being a relevant topic anymore. However, in reality, a number of open questions about the quality of the measurement exists. Even if the meters fulfill the established quality criteria when they receive approval, there is no independent institution that performs a regular, critical comparison of the quality of the measurement of all blood glucose meters after their approval. Such an institute could also evaluate the quality of the different batches of test strips. In addition, it can evaluate the impact of other factors that are known to have an impact on the quality of measurement, e.g., the ambient temperature and the hematocrit. Such an institution will be very helpful to counterbalance complaints by the patients, physicians and authorities about an industry that earns a lot of money but does not provide solutions for the topics raised.

Significant insulin dose errors may occur if blood glucose results are obtained from miscoded meters

OBJECTIVE

The objective of this study was to determine inaccuracies of miscoded blood glucose (BG) meters and potential errors in insulin dose based on values from these meters.

RESEARCH DESIGN

Fasting diabetic subjects at three clinical centers participated in a 2-hour meal tolerance test. At various times subjects' blood was tested on five BG meters and on a Yellow Springs Instruments laboratory glucose analyzer. Some meters were purposely miscoded. Using the BG values from these meters, along with three insulin dose algorithms, Monte Carlo simulations were conducted to generate ideal and simulated-meter glucose values and subsequent probability of insulin dose errors based on normal and empirical distribution assumptions.

RESULTS

Maximal median percentage biases of miscoded meters were +29% and -37%, while maximal median percentage biases of correctly coded meters were only +0.64% and -10.45% (p = 0.000, chi(2) test, df = 1). Using the low-dose algorithm and the normal distribution assumption, the combined data showed that the probability of insulin error of +/-1U, +/-2, +/-3, +/-4, and +/-5U for miscoded meters could be as high as 49.6, 50.0, 22.3, 1.4, and 0.04%, respectively. This is compared to manually, correctly coded meters where the probability of error of +/-1, +/-2, and +/-3U could be as high as 44.6, 7.1, and 0.49%, respectively. There was no instance of a +/-4 or +/-5U insulin dose error with a manually, correctly coded meter. For autocoded meters, the probability of +/-1 and +/-2U could be as high as 35.4 and 1.4%, respectively. For autocoded meters there were no calculated insulin dose errors above +/-2U. The probability of insulin misdosing with either manually, correctly coded or autocoded meters was significantly lower than that with miscoded meters. Results using empirical distributions showed similar trends of insulin dose errors.

CONCLUSIONS

Blood glucose meter coding errors may result in significant insulin dosing errors. To avoid error, patients should be instructed to code their meters correctly or be advised to use an autocoded meter that showed superior performance over manually, correctly coded meters in this study.

Problems and practical solutions in the external quality control of point of care devices with respect to the measurement of blood glucose

Point of care testing (POCT) is evolving at an ever increasing rate. This article deals mainly with the aspect of POCT for blood glucose and the problems of external quality assessment (EQA) of point of care devices (POCD). At the present time it is only possible to control precision with EQA, independent of the matrix of the test materials (synthetic polymer-base, plasma/serum, or processed whole blood). The German Federal Medical Council guidelines for laboratory performance allow an interlaboratory imprecision of +/-16%. The majority of POCD fulfill these requirements. The long-term stability of results--tested by repeated distribution of the same materials over a 12-month period--is excellent, and the performance of POCD under routine condtions is usually excellent in terms of result-comparability. The problems of accuracy in terms of control materials have still to be mastered.

Pancreatic B-cell function is altered by oxidative stress induced by acute hyperglycaemia

AIMS

Type 2 diabetes is preceded by a symptom-free period of impaired glucose tolerance (IGT). Pancreatic B-cell function decreases as glucose intolerance develops. In many patients with IGT, fasting blood glucose is within normal limits and hyperglycaemia occurs only postprandially. We examined whether pancreatic B-cell function changes during acute hyperglycaemia induced by oral glucose loading.

METHODS

We calculated the insulinogenic index (I.I.) as an indicator of pancreatic B-cell function and measured serum levels of thioredoxin, a marker of cellular redox state, and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, during a 75-g oral glucose tolerance test (OGTT) in 45 subjects [24 patients with normal glucose tolerance (NGT), 14 with IGT and seven with Type 2 diabetes].

RESULTS

Thioredoxin levels decreased after glucose loading [66.1 +/- 23.7, *59.3 +/- 22.4, *49.3 +/- 21.2 and *37.7 +/- 18.0 ng/ml, fasting (0 min) and at 30, 60 and 120 min, respectively; *P < 0.001 vs. fasting]. In contrast, concentrations of 8-OHdG peaked at 30 min and then gradually decreased (0.402 +/- 0.123, *0.440 +/- 0.120, 0.362 +/- 0.119 and 0.355 +/- 0.131 ng/ml, *P < 0.05 vs. fasting, P < 0.01 vs. 30 min). The insulinogenic index correlated with the change in thioredoxin levels (r = 0.34, P < 0.05). However, there was no relationship with the change in 8-OHdG levels from 0 to 30 min.

CONCLUSIONS

Hyperglycaemia in response to oral glucose impairs pancreatic B-cell function with decreasing thioredoxin levels. The augmented oxidative stress induced by hyperglycaemia may affect the cellular redox state. These findings strongly suggest that repeated postprandial hyperglycaemia may play an important role in the development and progression of diabetes mellitus.

Relationships between glycaemic abnormalities, obesity and insulin resistance in nondiabetic Polynesians of New Caledonia

OBJECTIVE

Polynesians in New Caledonia have an increased risk for developing diabetes, compared to Melanesians or Europeans. They are also more prone to obesity. The aim of this study was to analyse differences in the pre-diabetic state that may explain the varying susceptibility to diabetes between these three ethnic groups, focusing on the balance between insulin resistance and capacity of pancreatic cells to secrete insulin.

DESIGN AND SUBJECTS

The CALDIA Study is a population-based cross-sectional survey of diabetes prevalence conducted in New Caledonia. All participants who did not have diabetes, according to the results of a 0-2 h oral glucose tolerance test (n=392), were selected for analysis.

RESULTS

Compared to Europeans, Polynesians and Melanesians had significantly higher body mass indices (BMI) and waist-to-hip ratios (WHRs). Polynesians had higher fasting plasma glucose values than Europeans or Melanesians (6.03 mmol/l, vs 5.78 and 5.46, respectively; P<0.0001). Fasting plasma insulin level and the estimate of insulin resistance by homeostasis model assessment were not significantly different between the three ethnic groups. Homeostasis model assessment estimate of beta-cell secretory capacity was lower in Polynesians compared to the two other ethnic groups (83.1 mU/mmol, vs 119.3 and 125.2, respectively; P<0.02).

CONCLUSION

Despite a high prevalence of central obesity, as judged by high BMI and WHR, in Polynesians of New Caledonia, their high risk of diabetes may be more strongly related to a defect in insulin secretion capacity than to insulin resistance.

Beta-adrenergic and atrial natriuretic peptide interactions on human cardiovascular and metabolic regulation

CONTEXT

Atrial natriuretic peptide (ANP) has well-known cardiovascular effects and modifies lipid and carbohydrate metabolism in humans.

OBJECTIVE

The objective of the study was to determine the metabolic and cardiovascular interaction of beta-adrenergic receptors and ANP.

DESIGN

This was a crossover study, conducted 2004-2005.

SETTING

The study was conducted at an academic clinical research center.

PATIENTS

PATIENTS included 10 healthy young male subjects (body mass index 24 +/- 1 kg/m2).

INTERVENTION

We infused iv incremental ANP doses (6.25, 12.5, and 25 ng/kg.min) with and without propranolol (0.20 mg/kg in divided doses followed by 0.033 mg/kg.h infusion). Metabolism was monitored through venous blood sampling, im, and sc microdialysis and indirect calorimetry. Cardiovascular changes were monitored by continuous electrocardiogram and beat-by-beat blood pressure recordings.

MAIN OUTCOME MEASURES

Venous nonesterified fatty acid, glycerol, glucose, and insulin; and microdialysate glucose, glycerol, lactate, and pyruvate were measured.

RESULTS

ANP increased heart rate dose dependently. beta-Adrenergic receptor blockade abolished the response. ANP elicited a dose-dependent increase in serum nonesterified fatty acid and glycerol concentrations. The response was not suppressed with propranolol. Venous glucose and insulin concentrations increased with ANP, both without or with propranolol. ANP induced lipid mobilization in sc adipose tissue. In skeletal muscle, microdialysate lactate increased, whereas the lactate to pyruvate ratio decreased, both with and without propranolol. Higher ANP doses increased lipid oxidation, whereas energy expenditure remained unchanged. Propranolol tended to attenuate the increase in lipid oxidation.

CONCLUSIONS

Selected cardiovascular ANP effects are at least partly mediated by beta-adrenergic receptor stimulation. ANP-induced changes in lipid mobilization and glycolysis are mediated by another mechanism, presumably stimulation of natriuretic peptide receptors, whereas substrate oxidation might be modulated through adrenergic mechanisms.

Alcohol consumption is inversely associated with adherence to diabetes self-care behaviours

AIMS

Our aim was to examine the associations of alcohol consumption with six diabetes self-care behaviours.

METHODS

We determined levels of alcohol consumption and examined associations between alcohol consumption and six self-care behaviours in 65 996 adults with diabetes who received care through Kaiser Permanente Northern California and who responded to a 1994-1997 survey. Adherence with recommendations for self monitoring of blood glucose, HbA1c testing, and diabetes medications were determined from electronic records; smoking and use of diet and exercise to treat diabetes were self reported. Multiple logistic regression models were used to determine the associations between alcohol consumption (average number of drinks/day in the past year) and the probability of adherence to each self-care behaviour.

RESULTS

Current alcohol consumption was reported by 50.8% of adults with diabetes. In adjusted models, we observed a gradient of increasing risk for poor adherence to diabetes self-care behaviours with increasing alcohol consumption, starting with those who consume even one drink a day. Former drinkers had the greatest compliance with each self-care behaviour, except for current smoking.

CONCLUSIONS

Alcohol consumption is a marker for poorer adherence to diabetes self-care behaviours. These findings highlight the importance of routine assessment of alcohol intake in people with diabetes, particularly as half of adults with diabetes consume alcohol. Given extant evidence that moderate alcohol intake may have cardiovascular benefits for patients with diabetes, examination of the trade-offs between cardiovascular benefits vs. potential risk of lower adherence with self-care behaviours deserves study.

Blood pressure, levels of serum lipids, liver enzymes and blood glucose by aldehyde dehydrogenase 2 and drinking habit in Japanese men

OBJECTIVES

The association of blood pressure and levels of serum lipids, liver enzymes, blood glucose and aldehyde dehydrogenase 2 (ALDH2) with drinking habit was examined in Japanese men.

METHODS

The subjects were 264 men aged 39 to 80 years who were classified into the ALDH2 deficiency or sufficiency group using the ethanol patch test and the Tokyo University ALDH2 Phenotype Screening Test. A self-administered questionnaire including drinking habit was used. Blood pressure and the levels of biochemical markers in groups with ALDH2 sufficiency, ALDH2 deficiency and drinking habit were compared using multiple regression models for adjusting age, smoking habit, physical exercising habit and body mass index.

RESULTS

The levels of serum high-density lipoprotein cholesterol, triglycerides, aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (γ-GTP) were significantly higher in current drinkers of 20 g of ethanol or more per day than in nondrinkers of the ALDH2 sufficiency group. The levels of serum AST and γ-GTP in current drinkers of 20 g of ethanol or more per day, and fasting blood sugar in current drinkers of less than 20 g of ethanol per day were significantly higher than those in nondrinkers of the ALDH2 deficiency group.

CONCLUSIONS

These results suggest that alcohol consumption increases the levels of serum lipids and liver enzymes in ALDH2-sufficient individuals and liver enzymes and blood glucose levels in ALDH2-deficient individuals.

Fasting plasma glucose cutoff value for the prediction of future diabetes development: a study of middle-aged Koreans in a health promotion center

We determined optimal fasting plasma glucose (FPG) cutoff values predictive of future diabetes development in a group of middle-aged Koreans who visited a health promotion center. The medical records of 2,964 subjects, who attended the Health Promotion Center in 1998 and 2003, were examined. Subjects were classified into four groups according to their baseline FPG values (Group 1:FPG <5.0 mM/L; Group 2: 5.0< or =FPG <5.6 mM/L; Group 3: 5.6< or =FPG <6.1 mM/L; Group 4: 6.1< or =FPG <7.0 mM/L). No significant difference was observed between Group 1 and Group 2 in terms of diabetes incidence. However, incidence in Group 3 was significantly higher than that in Group 1 [hazards ratio 4.88 (1.65-14.41), p=0.004] and the hazards ratio in Group 4 for diabetes was 36.91 (13.11-103.61), p<0.001, versus Group 1. Receiver operator characteristics curve analysis showed that an FPG of 5.97 mM/L represents the lower limit and gives the best combination of sensitivity and specificity. Our data shows that the risk of future diabetes development started to increase below an FPG of 6.1 mM/L and suggests the importance of efforts to modify diabetes development risk factors at lower impaired fasting glucose levels.

Expression and regulation of latent TGF-beta binding protein-1 transcripts and their splice variants in human glomerular endothelial cells

Latent transforming growth factor (TGF)-beta-binding protein (LTBP) is required for the assembly, secretion, matrix association, and activation of latent TGF-beta complex. To elucidate the cell specific expression of the genes of LTBP-1 and their splice variants and the factors that regulate the gene expression, we cultured primary human glomerular endothelial cells (HGEC) under different conditions. Basal expression of LTBP-1 mRNA was suppressed in HGEC compared to WI-38 human embryonic lung fibroblasts. High glucose, H(2)O(2), and TGF-beta1 upregulated and vascular endothelial growth factor (VEGF) further downregulated LTBP-1 mRNA in HGEC. RT-PCR with a primer set for LTBP-1S produced many clones but no clone was gained with a primer set for LTBP-1L. Of 12 clones selected randomly, Sca I mapping and DNA sequencing revealed that only one was LTBP-1S and all the others were LTBP-1Sdelta53. TGF-beta1, but not high glucose, H(2)O(2) or VEGF, tended to increase LTBP-1Sdelta53 mRNA. In conclusion, HGEC express LTBP-1 mRNA which is suppressed at basal state but upregulated by high glucose, H(2)O(2), and TGF-beta1 and downregulated by VEGF. Major splice variant of LTBP-1 in HGEC was LTBP-1S 53. Modification of LTBP-1S 53 gene in HGEC may abrogate fibrotic action of TGF-beta1 but this requires confirmation.