Showing papers in "Journal of diabetes science and technology in 2012"

System Accuracy Evaluation of 43 Blood Glucose Monitoring Systems for Self-Monitoring of Blood Glucose according to DIN EN ISO 15197

Abstract: Background: The accuracy of systems for self-monitoring of blood glucose is important, as reliable measurement results are a prerequisite for therapeutic decisions. Methods: This system accuracy evaluation study was performed according to DIN EN ISO 15197:2003 for 43 Conformite Europeenne (CE)-labeled blood glucose (BG) monitoring systems. Measurement results of each system were compared with results of the designated comparison method (manufacturer’s measurement procedure): glucose oxidase method (YSI 2300 glucose analyzer) or hexokinase method (Hitachi 917/ cobas 501). Results: Complete assessment according to the International Organization for Standardization (ISO) standard was performed for 34 out of 43 systems, and 27 (79.4%) meet the requirements of the standard, i.e., ≥95% of their results showed at least the minimum acceptable accuracy. For 9 of the 43 systems, complete accuracy assessment was not performed due to an oxygen sensitivity (manufacturer’s labeling). The bias (according to Bland and Altman) of all 43 evaluated systems ranged from -14.1% to +12.4%. Conclusions: From the 34 systems completely assessed, 7 systems did not fulfill the minimal accuracy requirements of the ISO standard. The CE mark apparently does not guarantee that all BG systems provide accuracy according to the standard. Because inaccurate systems bear the risk of false therapeutic decisions, regular and standardized evaluation of BG meters and test strips should be requested in order to ensure adherence to quality standards.

Mobile Health Applications to Assist Patients with Diabetes: Lessons Learned and Design Implications

Abstract: Self-management is critical to achieving diabetes treatment goals. Mobile phones and Bluetooth® can supportself-management and lifestyle changes for chronic diseases such as diabetes. A mobile health (mHealth) research platform--the Few Touch Application (FTA)--is a tool designed to support the self-management of diabetes. The FTA consists of a mobile phone-based diabetes diary, which can be updated both manually from user input and automatically by wireless data transfer, and which provides personalized decision support for the achievement of personal health goals. Studies and applications (apps) based on FTAs have included: (1) automatic transfer of blood glucose (BG) data; (2) short message service (SMS)-based education for type 1diabetes (T1DM); (3) a diabetes diary for type 2 diabetes (T2DM); (4) integrating a patient diabetes diary with health care (HC) providers; (5) a diabetes diary for T1DM; (6) a food picture diary for T1DM; (7) physical activity monitoring for T2DM; (8) nutrition information for T2DM; (9) context sensitivity in mobile self-help tools; and (10) modeling of BG using mobile phones. We have analyzed the performance of these 10 FTA-based apps to identify lessons for designing the most effective mHealth apps. From each of the 10 apps of FTA, respectively, we conclude: (1) automatic BG data transfer is easy to use and provides reassurance; (2) SMS-based education facilitates parent-child communication in T1DM; (3) the T2DM mobile phone diary encourages reflection; (4) the mobile phone diary enhances discussion between patients and HC professionals; (5) the T1DM mobile phone diary is useful and motivational; (6) the T1DM mobile phone picture diary is useful in identifying treatment obstacles; (7) the step counter with automatic data transfer promotes motivation and increases physical activity in T2DM; (8) food information on a phone for T2DM should not be at a detailed level; (9) context sensitivity has good prospects and is possible to implement on today's phones; and (10) BG modeling on mobile phones is promising for motivated T1DM users. We expect that the following elements will be important in future FTA designs: (A) automatic data transfer when possible; (B) motivational and visual user interfaces; (C) apps with considerable health benefits in relation to the effort required; (D) dynamic usage, e.g., both personal and together with HC personnel, long-/short-term perspective; and (E) inclusion of context sensitivity in apps. We conclude that mHealth apps will empower patients to take a more active role in managing their own health.

The Accuracy of Point-of-Care Glucose Measurements

Abstract: Control of blood glucose (BG) in an acceptable range is a major therapy target for diabetes patients in both the hospital and outpatient environments. This review focuses on the state of point-of-care (POC) glucose monitoring and the accuracy of the measurement devices. The accuracy of the POC glucose monitor depends on device methodology and other factors, including sample source and collection and patient characteristics. Patient parameters capable of influencing measurements include variations in pH, blood oxygen, hematocrit, changes in microcirculation, and vasopressor therapy. These elements alone or when combined can significantly impact BG measurement accuracy with POC glucose monitoring devices (POCGMDs). In general, currently available POCGMDs exhibit the greatest accuracy within the range of physiological glucose levels but become less reliable at the lower and higher ranges of BG levels. This issue raises serious safety concerns and the importance of understanding the limitations of POCGMDs. This review will discuss potential interferences and shortcomings of the current POCGMDs and stress when these may impact the reliability of POCGMDs for clinical decision-making.

The impact of mobile monitoring technologies on glycosylated hemoglobin in diabetes: a systematic review

Abstract: Background: A new development in the field of telehealth is the use of mobile health technologies (mhealth) to help patients record and track medical information. Mhealth appears particularly advantageous for conditions that require intense and ongoing monitoring, such as diabetes, and where people are of working age and not disabled. This review aims to evaluate the evidence for the effectiveness of mhealth interventions in diabetes management on glycosylated hemoglobin. Method: A comprehensive search strategy was developed and applied to eight electronic databases to identify studies that investigated the clinical effectiveness of mobile-based applications that allowed patients to record and send their blood glucose readings to a central server. The eligibility of 8543 papers was assessed against the selection criteria, and 24 papers were reviewed. All studies reviewed were assessed for quality using a standardized quality assessment tool. Results: Results for patients with type 1 and type 2 diabetes were examined separately. Study variability and poor reporting made comparison difficult, and most studies had important methodological weaknesses. Evidence on the effectiveness of mhealth interventions for diabetes was inconsistent for both types of diabetes and remains weak.

Insulin infusion set: the Achilles heel of continuous subcutaneous insulin infusion.

Abstract: Continuous subcutaneous insulin infusion from an insulin pump depends on reliable transfer of the pumped insulin to the subcutaneous insulin depot by means of an insulin infusion set (IIS). Despite their widespread use, the published knowledge about IISs and related issues regarding the impact of placement and wear time on insulin absorption/insulin action is relatively small. We also have to acknowledge that our knowledge is limited with regard to how often patients encounter issues with IISs. Reading pump wearer blogs, for instance, suggests that these are a frequent source of trouble. There are no prospective clinical studies available on current IIS and insulin formulations that provide representative data on the type and frequency of issues with infusion sets. The introduction of new IISs and patch pumps may foster a reassessment of available products and of patient problems related to their use. The aim of this review is to summarize the current knowledge and recommendations about IISs and to highlight potential directions of IIS development in order to make insulin absorption safer and more efficient.

Stochastic Targeted (STAR) Glycemic Control: Design, Safety, and Performance

Abstract: Introduction:Tight glycemic control (TGC) has shown benefits but has been difficult to achieve consistently. STAR (Stochastic TARgeted) is a flexible, model-based TGC approach that directly accounts for intra- and interpatient variability with a stochastically derived maximum 5% risk of blood glucose (BG) below 72 mg/dl. This research assesses the safety, efficacy, and clinical burden of a STAR TGC controller modulating both insulin and nutrition inputs in virtual and clinical pilot trials.Methods:Clinically validated virtual trials using data from 370 patients in the SPRINT (Specialized Relative Insulin and Nutrition Titration) study were used to design the STAR protocol and test its safety, performance, and required clinical effort prior to clinical pilot trials. Insulin and nutrition interventions were given every 1–3 h as chosen by the nurse to allow them to manage workload.Interventions were designed to maximize the overlap of the model-predicted (5–95th percentile) range of BG outcomes with the 72–1...

Prediction of the risk to develop diabetes-related late complications by means of the glucose pentagon model: analysis of data from the Juvenile Diabetes Research Foundation continuous glucose monitoring study

Abstract: Background:By taking parameters into account that describe the variability of continuously monitored glucose and long-term metabolic control [hemoglobin A1c (HbA1c)], the glucose pentagon model (GPM) allows characterization of the glucose profile of individual patients with diabetes in a graphical format. A glycemic risk parameter (GRP) derived from this model might allow a better prognosis of the risk to develop diabetes-related complications than the HbA1c.Methods:To evaluate this hypothesis, we analyzed a subset of data from the Juvenile Diabetes Research Foundation continuous glucose monitoring (CGM) study. The values of the different parameters that are integrated in the GPM were extracted automatically from CGM profiles registered before and after 6 months by means of the Medtronic CGM system in 108 patients.Results:In these patients, the significant reduction in HbA1c from 7.4% to 7.0% was accompanied by a reduction in glycemia from 164 to 156 mg/dl, standard deviation from 61 to 57 mg/dl, area und...

Mobile phone-based video messages for diabetes self-care support.

Abstract: Background:This study examined whether mobile phone-based, one-way video messages about diabetes self-care improve hemoglobin A1c (A1C) and self-monitoring of blood glucose (SMBG).Methods:This was a 1-year prospective randomized trial with two groups. The active intervention lasted 6 months. The study enrolled 65 people with A1C >8.0% who were established (>6 months) patients in the endocrinology clinics of the Walter Reed Health Care System. Participants were randomized to receive “usual care” or self-care video messages from their diabetes nurse practitioner. Video messages were sent daily to cell phones of study participants. Hemoglobin A1c and SMBG data were collected at 0, 3, 6, 9, and 12 months.Results:Participants who received the messages had a larger rate of decline in A1C than people who received usual care (0.2% difference over 12 months, adjusting for covariates; p = .002 and p = .004 for the interaction between time and group and for the quadratic effect of time by group, respectively). Hemog...

Overview of fluorescence glucose sensing: a technology with a bright future.

Abstract: Fluorescence represents a promising alternative technology to electrochemistry and spectroscopy for accurate analysis of glucose in diabetes; however, no implanted fluorescence glucose assay is currently commercially available. The method depends on the principle of fluorescence, which is the emission of light by a substance after absorbing light. A fluorophore is a molecule that will absorb energy of a specific wavelength and reemit energy at a different wavelength. A fluorescence glucose-sensing molecule can be constructed to increase or decrease in fluorescence from baseline according to the ambient concentration of glucose. A quantum dot is a semiconductor crystal that can serve as a sensor by fluorescing at a desired wavelength or color, depending on the crystal size and materials used. If receptor molecules for glucose can be adsorbed to single-wall carbon nanotubules, then the resulting binding of glucose to these receptors will alter the nanotubes’ fluorescence. Fluorescence glucose sensors can provide a continuous glucose reading by being embedded into removable wire-shaped subcutaneous or intravenous catheters as well as other types of implanted structures, such as capsules, microcapsules, microbeads, nano-optodes, or capillary tubes. Fluorescence glucose-sensing methods, which are under development, offer four potential advantages over commercially used continuous glucose monitoring technologies: (1) greater sensitivity to low concentrations of glucose, (2) the possibility of constructing sensors that operate most accurately in the hypoglycemic range by using binding proteins with disassociation constants in this range, (3) less need to recalibrate in response to local tissue reactions around the sensor, and (4) no need to implant either a transmitter or a power source for wireless communication of glucose data. Fluorescence glucose sensors also have four significant disadvantages compared with commercially used continuous glucose monitoring technologies: (1) a damaging foreign body response; (2) a sensitivity to local pH and/or oxygen, which can affect the dye response; (3) potential toxicity of implanted dyes, especially if the implanted fluorophore cannot be fully removed; and (4) the necessity of always carrying a dedicated light source to interrogate the implanted sensor. Fluorescence sensing is a promising method for measuring glucose continuously, especially in the hypoglycemic range. If currently vexing technical and engineering and biocompatibility problems can be overcome, then this approach could lead to a new family of continuous glucose monitors.

Effect of Insulin Feedback on Closed-Loop Glucose Control: A Crossover Study

Abstract: Background: Closed-loop (CL) insulin delivery systems utilizing proportional-integral-derivative (PID) controllers have demonstrated susceptibility to late postprandial hypoglycemia because of delays between insulin delivery and blood glucose (BG) response. An insulin feedback (IFB) modification to the PID algorithm has been introduced to mitigate this risk. We examined the effect of IFB on CL BG control. Methods: Using the Medtronic ePID CL system, four subjects were studied for 24 h on PID control and 24 h during a separate admission with the IFB modification (PID + IFB). Target glucose was 120 mg/dl; meals were served at 8:00 AM, 1:00 PM, and 6:00 PM and were identical for both admissions. No premeal manual boluses were given. Reference BG excursions, defined as incremental glucose rise from premeal to peak, and postprandial BG area under the curve (AUC; 0–5 h) were compared. Results are reported as mean ± standard deviation. Results: The PID + IFB control resulted in higher mean BG levels compared with PID alone (153 ± 54 versus 133 ± 56 mg/dl; p < .0001). Postmeal BG excursions (114 ± 28 versus 114 ± 47 mg/dl) and AUCs (285 ± 102 versus 255 ± 129 mg/dl/h) were similar under both conditions. Total insulin delivery averaged 57 ± 20 U with PID versus 45 ± 13 U with PID + IFB (p = .18). Notably, eight hypoglycemic events (BG < 60 mg/dl) occurred during PID control versus none during PID + IFB. Conclusions: Addition of IFB to the PID controller markedly reduced the occurrence of hypoglycemia without increasing meal-related glucose excursions. Higher average BG levels may be attributable to differences in the determination of system gain (Kp) in this study. The prevention of postprandial hypoglycemia suggests that the PID + IFB algorithm may allow for lower target glucose selection and improved overall glycemic control.

Motivating effects of cooperative exergame play for overweight and obese adolescents.

Abstract: Background: Exergames (i.e., video games that require gross motor activity) may provide intrinsically motivating experiences that engage youth in sustained physical activity. Method: Thirty-one low-income 15- to 19-year-old overweight and obese African American adolescents were randomly assigned to a competitive exergame (n = 17) or a cooperative exergame (n = 14) condition. Participants played a preassigned Wii Active exergame routine that took between 30 and 60 min each school day, and sessions occurred during lunch time or an after-school program over a 6 month period. Participation was voluntary, so students decided whether to come or not on a given day. Cooperative exergame players worked together with a peer to expend calories and earn points, while competitive exergame players competed individually against a peer to expend calories and earn points. Motivation was measured through surveys and interviews at the end of the intervention, and energy expenditure was measured by accelerometry during game play. Results: Compared with the competitive group, the cooperative players were significantly more intrinsically motivated to play (p = .034, partial eta-squared = 0.366) and more psychologically attracted to the design of the exergame (p = .034, partial eta-squared = 0.320). Intrinsic motivation was significantly positively correlated with energy expenditure during game play: individuals who were motivated by control/choice had higher energy expenditure (p = .026), and those who were more goal motivated (p = .004) and more immersed in game play (p = .024) had lower energy expenditure during game play. Conclusions: Cooperative exergame play produced higher intrinsic motivation to play the exergame than competitive exergame play did. Intrinsic motivation that came from a desire for control/choice was related to higher energy expenditure during game play. Cooperative exergame play holds promise as a method for engaging overweight and obese youth in physical activity.

Use of an Automated Bolus Calculator Reduces Fear of Hypoglycemia and Improves Confidence in Dosage Accuracy in Patients with Type 1 Diabetes Mellitus Treated with Multiple Daily Insulin Injections

Abstract: Background: Many patients do not intensify their insulin regimens. It is believed that lack of adherence may be largely due to fear of hypoglycemia. We hypothesized that utilization of an automated bolus calculator (bolus advisor) might reduce fear of hypoglycemia and encourage patients to achieve improved glycemic control. Method: We surveyed 1,412 type 1 diabetes mellitus (T1DM) patients treated with multiple daily insulin injection therapy at 270 hospitals in the United Kingdom and Republic of Ireland to assess their attitudes and behaviors regarding insulin therapy after use of a bolus advisor (Accu-Chek ® Aviva Expert blood glucose meter and bolus advisor system, Roche Diagnostics). The device automatically calculates bolus dosages based on current blood glucose values, anticipated meal intake, and other parameters. Results: Five hundred eighty-eight T1DM patients responded to the survey. Respondents were predominantly female, age 15 years. Respondents had 4–12 weeks prior experience using the bolus advisor. 76.7% of respondents indicated current bolus advisor use to calculate insulin boluses for meals/snacks always or quite often. 52.0% of respondents indicated that fear of hypoglycemia was reduced (39.0%) or significantly reduced (13.0%). 78.8% indicated that confidence in the insulin dose calculation improved (50.8%) or significantly improved (28.0%). 89.3% indicated that the bolus advisor made bolus calculation easy or very easy compared with manual calculation. Conclusions: Most patients felt that using the bolus advisor was easier than manual bolus calculation, improved their confidence in the accuracy of their bolus dosage, and reduced their fear of hypoglycemia. Randomized trials are needed to confirm these perceptions and determine whether bolus advisor use improves clinical outcomes.

Designing serious video games for health behavior change: current status and future directions.

Abstract: Serious video games for health are designed to entertain while changing a specific health behavior. This article identifies behavioral principles that can guide the development of serious video games focused on changing a variety of health behaviors, including those attempting to decrease risk of obesity and type 2 diabetes. Guidelines discussed include how to develop video games that provide a solid foundation for behavior change by enhancing a player’s knowledge and skill, ways in which personal mastery experiences can be incorporated into a video game environment, using game characters and avatars to promote observational learning, creating personalized experiences through tailoring, and the importance of achieving a balance between “fun-ness” and “seriousness.” The article concludes with suggestions for future research needed to inform this rapidly growing field.

Ultrafast-acting insulins: state of the art.

Abstract: Optimal coverage of prandial insulin requirements remains an elusive goal. The invention of rapid-acting insulin analogs (RAIAs) was a big step forward in reducing postprandial glycemic excursions in patients with diabetes in comparison with using regular human insulin; however, even with these, the physiological situation cannot be adequately mimicked. Developing ultrafast-acting insulins (UFIs)—showing an even more rapid onset of action and a shorter duration of action after subcutaneous (SC) administration—is another step forward in achieving this goal. The need for UFIs has been gradually recognized over the years, and subsequently, a number of different approaches to cover this need are in clinical development. A rapid increase in circulating insulin levels can be achieved by different measures: modification of the primary structure of insulin molecule (as we know from RAIAs), addition of excipients that enhance the appearance in the monomeric state post-injection, or addition of enzymes that enable more free spreading of the insulin molecules in the SC tissue. Other measures to increase the insulin absorption rate increase the local blood flow nearby the insulin depot in the SC tissue, injecting the insulin intradermally or applying via another route, e.g., the lung. The development of these approaches is in different stages, from quite early stages to nearing market authorization. In time, daily practice will show if the introduction of UFIs will fulfill their clinical promise. In this review, the basic idea for UFIs will be presented and the different approaches will be briefly characterized.

Clinical use of U-500 regular insulin: review and meta-analysis

Abstract: The use of U-500 regular insulin (U-500R) to treat diabetic patients with severe insulin resistance has increased. In this review, we performed a meta-analysis of PubMed studies reporting the use of U-500R to evaluate the effects of U-500R on hemoglobin A1c (HbA1c), body weight, and total daily insulin dose (TDD). These studies included 310 patients using U-500R as multiple daily injections (MDI) and 55 patients using U-500R via continuous subcutaneous insulin infusion (CSII). Overall, the use of U-500R as MDI resulted in a significant HbA1c reduction of 1.59%, a significant weight gain of 4.38 kg, and a significant increase in TDD by 51.9 units. The use of U-500R via CSII resulted in a similarly significant HbA1c reduction of 1.64% but a nonsignificant weight gain and a nonsignificant change in TDD. The use of U-500 regular insulin both as MDI and via CSII was not reported to be associated with severe hypoglycemia but was associated with an increase in patient satisfaction as well as in cost savings. Suggestions in initiating U-500R in the outpatient setting using U-500R in hospitalized patients are reviewed. In addition, precautions for avoiding prescription and patient errors are discussed.

Lot-to-Lot Variability of Test Strips and Accuracy Assessment of Systems for Self-Monitoring of Blood Glucose according to ISO 15197

Abstract: Background:Accurate and reliable blood glucose (BG) measurements require that different test strip lots of the same BG monitoring system provide comparable measurement results. Only a small number of studies addressing this question have been published.Methods:In this study, four test strip lots for each of five different BG systems [Accu-Chek® Aviva (system A), FreeStyle Lite® (system B), GlucoCheck XL (system C), Pura™/mylife™ Pura (system D), and OneTouch® Verio ™ Pro (system E)] were evaluated with procedures according to DIN EN ISO 15197:2003. The BG system measurement results were compared with the manufacturer's measurement procedure (glucose oxidase or hexokinase method). Relative bias according to Bland and Altman and system accuracy according to ISO 15197 were analyzed. A BG system consists of the BG meter itself and the test strips.Results:The maximum lot-to-lot difference between any two of the four evaluated test strip lots per BG system was 1.0% for system E, 2.1% for system A, 3.1% for syst...

Bioelectrical impedance assessment of wound healing.

Abstract: Objective assessment of wound healing is fundamental to evaluate therapeutic and nutritional interventions and to identify complications. Despite availability of many techniques to monitor wounds, there is a need for a safe, practical, accurate, and effective method. A new method is localized bioelectrical impedance analysis (BIA) that noninvasively provides information describing cellular changes that occur during healing and signal complications to wound healing. This article describes the theory and application of localized BIA and provides examples of its use among patients with lower leg wounds. This promising method may afford clinicians a novel technique for routine monitoring of interventions and surveillance of wounds.

Performance of a Glucose Meter with a Built-in Automated Bolus Calculator versus Manual Bolus Calculation in Insulin-Using Subjects:

Abstract: Background: Patients consider multiple parameters in adjusting prandial insulin doses for optimal glycemic control. Difficulties in calculations can lead to incorrect doses or induce patients to administer fixed doses, rely on empirical estimates, or skip boluses. Method: A multicenter study was conducted with 205 diabetes subjects who were on multiple daily injections of rapid/ short-acting insulin. Using the formula provided, the subjects manually calculated two prandial insulin doses based on one high and one normal glucose test result, respectively. They also determined the two doses using the FreeStyle InsuLinx Blood Glucose Monitoring System, which has a built-in, automated bolus calculator. After dose determinations, the subjects completed opinion surveys. Results: Of the 409 insulin doses manually calculated by the subjects, 256 (63%) were incorrect. Only 23 (6%) of the same 409 dose determinations were incorrect using the meter, and these errors were due to either confirmed or potential deviations from the study instructions by the subjects when determining dose with meter. In the survey, 83% of the subjects expressed more confidence in the meter-calculated doses than the manually calculated doses. Furthermore, 87% of the subjects preferred to use the meter than manual calculation to determine prandial insulin doses. Conclusions: Insulin-using patients made errors in more than half of the manually calculated insulin doses. Use of the automated bolus calculator in the FreeStyle InsuLinx meter minimized errors in dose determination. The patients also expressed confidence and preference for using the meter. This may increase adherence and help optimize the use of mealtime insulin.

The challenges of measuring glycemic variability.

Abstract: This commentary reviews several of the challenges encountered when attempting to quantify glycemic variability and correlate it with risk of diabetes complications. These challenges include (1) immaturity of the field, including problems of data accuracy, precision, reliability, cost, and availability; (2) larger relative error in the estimates of glycemic variability than in the estimates of the mean glucose; (3) high correlation between glycemic variability and mean glucose level; (4) multiplicity of measures; (5) correlation of the multiple measures; (6) duplication or reinvention of methods; (7) confusion of measures of glycemic variability with measures of quality of glycemic control; (8) the problem of multiple comparisons when assessing relationships among multiple measures of variability and multiple clinical end points; and (9) differing needs for routine clinical practice and clinical research applications.

Coverage of Prandial Insulin Requirements by Means of an Ultra-Rapid-Acting Inhaled Insulin

Abstract: Barriers to the use of prandial insulin regimens include inadequate synchronization of insulin action to postprandial plasma glucose excursions as well as a significant risk of hypoglycemia and weight gain. Technosphere® insulin (TI) is an inhaled ultra-rapid-acting human insulin that is quickly absorbed in the alveoli. With a time to maximum plasma drug concentration of approximately 14 min and a time to maximum effect of 35 to 40 min, TI more closely matches the postprandial insulin concentrations seen in nondiabetic individuals. Studies have shown that long-term administration of prandial TI in combination with long-acting basal insulin results in reductions in hemoglobin A1c comparable to conventional subcutaneously injected prandial insulins but with improved control of early postprandial BG. Furthermore, TI has been associated with less weight gain and a lower incidence of hypoglycemia, which may enhance patient satisfaction and acceptability of insulin therapy. This review discusses the clinical properties of TI and proposes strategies for optimal use.

Impact of a modified needle tip geometry on penetration force as well as acceptability, preference, and perceived pain in subjects with diabetes.

Abstract: Background: Multiple factors impact subcutaneous insulin injection pain. Injection devices [e.g., syringe or pen needle (PN)] affect pain due to needle length, diameter, needle polishing and lubrication, and needle tip geometry. Methods: We evaluated a modified 5-bevel PN tip in 32 G × 4 mm 31 G × 5 mm and 8 mm PNs vs the equivalent marketed 3-bevel PNs in laboratory penetration force testing, as well as in insulin-taking subjects for overall acceptability, comparative pain, and preference. The clinical tests were done in three ways: paired insertions with the subjects blinded to PN tip geometry, after brief at-home use of 5-bevel PNs, and again with subjects informed about each needle’s tip geometry in paired insertions. Results: Average penetration force in a skin substitute was 23% lower with the 5-bevel PNs vs similar 3-bevel PNs (p ≤ 0.01). In blinded testing and after at-home use, patients rated the 5-bevel needle as acceptable. After shortterm home use, patients rated the 5-bevel PN less painful and preferable to their usual PN (both p < 0.01). In paired, informed testing, the 5-bevel PN was less painful and preferred to subjects’ currently used needles (p ≤ 0.01) and to other marketed PNs (p < 0.01). Conclusions: Needle tip geometry affects penetration force. When blinded, patients did not distinguish differences in PN tip geometry with fine-gauge PN insertions. A 5-bevel needle tip is perceived as less painful and is preferred by subjects following home use for usual injections. Similar results occurred when patients were informed that they were using a needle with a modified tip.

Retinal vascular geometry in Asian persons with diabetes and retinopathy

Abstract: Purpose: Our purpose was to examine the relationship of retinal vascular parameters with diabetes and retinopathy in an older Asian population. Methods: Retinal photographs from participants of a population-based survey of Asian Malay persons aged 40–80 years were analyzed. Specific retinal vascular parameters (tortuosity, branching angle, fractal dimension, and caliber) were measured using a semiautomated computer-based program. Diabetes was defined as random plasma glucose ≥ 11.1 mmol/liter, the use of diabetes medication, or physician-diagnosed diabetes. Retinopathy signs were graded from photographs using the modified Airlie House classification system. Results: A total of 2735 persons were included in the study. Persons with diabetes (n = 594) were more likely to have straighter (less tortuous) arterioles and wider arteriolar and venular caliber than those without diabetes (n = 2141). Among subjects with diabetes, those with retinopathy had wider venular caliber than those without retinopathy (211.3 versus 204.9 µm, p = .001). Among nondiabetic subjects, however, those with retinopathy had more tortuous venules than those without retinopathy [5.19(×10 4 ) versus 4.27(×10 4 ), p < .001].

Video games for diabetes self-management: examples and design strategies.

Abstract: The July 2012 issue of the Journal of Diabetes Science and Technology includes a special symposium called "Serious Games for Diabetes, Obesity, and Healthy Lifestyle." As part of the symposium, this article focuses on health behavior change video games that are designed to improve and support players' diabetes self-management. Other symposium articles include one that recommends theory-based approaches to the design of health games and identifies areas in which additional research is needed, followed by five research articles presenting studies of the design and effectiveness of games and game technologies that require physical activity in order to play. This article briefly describes 14 diabetes self-management video games, and, when available, cites research findings on their effectiveness. The games were found by searching the Health Games Research online searchable database, three bibliographic databases (ACM Digital Library, PubMed, and Social Sciences Databases of CSA Illumina), and the Google search engine, using the search terms "diabetes" and "game." Games were selected if they addressed diabetes self-management skills.

Glycemic levels in critically ill patients: are normoglycemia and low variability associated with improved outcomes?

Abstract: Background: Critically ill patients often experience high levels of insulin resistance and stress-induced hyperglycemia, which may negatively impact outcomes. In 2001, Van den Berghe and coauthors used intensive insulin therapy (IIT) to control blood glucose (BG) to normal levels and reported a reduction in intensive care unit (ICU) mortality from 8% to 4.6%. Many studies tried to replicate these results, with some showing reduced mortality, others failing to match these results, and many seeing no clinically significant difference. The interpretation of results is important when drawing conclusions about the benefits and risks of IIT. There is the potential for negative results to be falsely negative due to unintended patient crossover or cohort overlap. Aim:

Introduction to Human Factors

Abstract: This paper provides an introduction to "human factors engineering," an applied science that seeks to optimize usability and safety of systems. Human factors engineering pursues this goal by aligning system design with the perceptual, cognitive, and physical capabilities of users. Human factors issues loom large in the diabetes management domain because patients and health care professionals interact with a complex variety of systems, including medical device hardware and software, which are themselves embedded within larger systems of institutions, people, and processes. Usability considerations must be addressed in these systems and devices to ensure safe and effective diabetes management.

Comparison of known food weights with image-based portion-size automated estimation and adolescents' self-reported portion size.

Abstract: Background: Diet is a critical element of diabetes self-management. An emerging area of research is the use of images for dietary records using mobile telephones with embedded cameras. These tools are being designed to reduce user burden and to improve accuracy of portion-size estimation through automation. The objectives of this study were to (1) assess the error of automatically determined portion weights compared to known portion weights of foods and (2) to compare the error between automation and human. Methods: Adolescents (n = 15) captured images of their eating occasions over a 24 h period. All foods and beverages served were weighed. Adolescents self-reported portion sizes for one meal. Image analysis was used to estimate portion weights. Data analysis compared known weights, automated weights, and self-reported portions. Results: For the 19 foods, the mean ratio of automated weight estimate to known weight ranged from 0.89 to 4.61, and 9 foods were within 0.80 to 1.20. The largest error was for lettuce and the most accurate was strawberry jam. The children were fairly accurate with portion estimates for two foods (sausage links, toast) using one type of estimation aid and two foods (sausage links, scrambled eggs) using another aid. The automated method was fairly accurate for two foods (sausage links, jam); however, the 95% confidence intervals for the automated estimates were consistently narrower than human estimates. Conclusions:

Risk factors for inpatient hypoglycemia during subcutaneous insulin therapy in non-critically ill patients with type 2 diabetes.

Abstract: Objective: We aimed to determine risk factors associated with hypoglycemia during subcutaneous insulin therapy in non-critically ill patients with type 2 diabetes. Methods: We conducted an analysis of three randomized control trials using basal/bolus regimen and regular sliding scale insulin (SSI) in patients with diabetes admitted to medical and surgical settings. Results: We analyzed medical records of 261 general medicine and 211 noncardiac surgery patients treated with basal/ bolus regimen with glargine/glulisine (n = 169), detemir/aspart (n = 67), neutral protamine Hagedorn/regular (n = 63), or with SSI (n = 173). The overall frequency of mild and severe hypoglycemia (<70 and <40 mg/dl) was 19% and 2%, respectively. During treatment, medical patients experienced a higher number of hypoglycemia than surgical patients (23% versus 13%; p = .005), but the rate of severe hypoglycemia was similar between groups (1.9% versus 1.9%; p = not significant). Increasing age, impaired kidney function (glomerular filtration rate < 60 ml/min), total daily insulin dose, and type of insulin regimen (basal/bolus versus SSI) during hospitalization were important contributors for hypoglycemia in both medical and surgical patients. Among these variables, increasing age and type of insulin regimen (basal/bolus versus SSI) were found to be independent predictors of hypoglycemic events. Conclusions: Mild hypoglycemic events are common during subcutaneous insulin therapy in medical and surgical patients with type 2 diabetes. Increasing age, impaired renal function, daily insulin dose, and insulin regimen (basal/bolus versus SSI) are important predictors of hypoglycemia during insulin therapy in patients with type 2 diabetes mellitus.

The effect of diabetes on hospital readmissions.

Abstract: Hospital readmission is an important contributor to total medical expenditures and is an emerging indicator of quality of care. Diabetes, similar to other chronic medical conditions, is associated with increased risk of hospital readmission. Risk factors include previous hospitalization, extremes in age, and socioeconomic barriers. Preliminary studies suggest that acute and/or chronic glycemic control may be of importance when diabetes is the primary diagnosis or when it is a comorbidity. Very limited evidence from prospective randomized controlled trials aimed at improving glycemic control is available. However, whether one concludes that inpatient or outpatient glycemic control is partly responsible for reduced hospitalizations, attention to glycemic control in the hospital may facilitate sustained glycemic control post-discharge. Limited prospective and retrospective evidence suggest that the involvement of a diabetes specialist team may improve readmission rates, but attention to more generalized comprehensive approaches may also be worthwhile. Prospective interventional studies targeting interventions for improving glycemic control are needed to determine whether glycemic control impacts readmission rates.

Comparative Analysis of the Efficacy of Continuous Glucose Monitoring and Self-Monitoring of Blood Glucose in Type 1 Diabetes Mellitus:

Abstract: Background: Self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) have been proven effective in improving hemoglobin A1c (HbA1c) and in reducing hypoglycemia in patients with type 1 diabetes mellitus (T1DM). It is not clear, however, if CGM provides further efficacy and safety benefits beyond SMBG in the management of T1DM. Methods: MEDLINE (1966–November 2009), COCHRANE REGISTRY (all years), and EMBASE (1980–November 2009), and article bibliographies were searched for randomized controlled trials (RCTs) investigating the use of CGM in patients with T1DM, with clinical outcomes, including HbA1c and hypoglycemia and/or hyperglycemia. Results: Fourteen RCTs met eligibility criteria [n = 1188 patients, 97.4% with T1DM, age 29.0 ± 14.3 years, diabetes duration 11.7 ± 7.0 years, and baseline HbA1c 8.3 ± 0.8% (mean ± standard deviation)]. Compared with SMBG, the use of CGM was associated with a greater reduction in HbA1c [-0.3% (confidence interval: 0.4, -0.2), p < .0001]. The number of hypoglycemic events was not significantly different between the CGM and SMBG groups (0.52 ± 0.52 versus 0.52 ± 0.63 events/day, p = .5), but duration of hypoglycemia was shorter for the CGM group (75 ± 39 versus 89 ± 19 min/day), with an incremental reduction of hypoglycemia duration of -15.2 min/day, p < .0001. Continuous glucose monitoring also resulted in a shorter duration of hyperglycemia than SMBG (172 ± 125 versus 217 ± 152 min/day, p = .04). Conclusions: The use of CGM is associated with improvement in metabolic control in T1DM, with significant short- and long-term reductions in HbA1c and reduction in the duration of periods of hypoglycemia and hyperglycemia versus SMBG.

Nonhuman Primates and other Animal Models in Diabetes Research

Abstract: Animal models are important for determining the pathogenesis of and potential treatments for obesity and diabetes. Nonhuman primates (NHPs) are particularly useful for studying these disorders. As in humans, type 2 diabetes mellitus is the most common form of diabetes in NHPs and occurs more often in older obese animals, with a metabolic progression from insulin resistance (IR) and impaired glucose tolerance to overt diabetes. Histopathologic changes in pancreatic islets are also similar to those seen in humans with diabetes. Initially, there is islet hyperplasia with abundant insulin production to compensate for IR, followed by insufficient insulin production with replacement of islets with islet-associated amyloid. Diabetic NHPs also have adverse changes in plasma lipid and lipoprotein concentrations, biomarkers of obesity, inflammation, and oxidative stress, and protein glycation that contribute to the numerous complications of the disease. Furthermore, sex hormones, pregnancy, and environmental factors (e.g., diet and stress) affect IR and can also contribute to diabetes progression in NHPs. Additionally, due to their similar clinical and pathologic characteristics, NHPs have been used in many pharmacological studies to assess new therapeutic agents. For these reasons, NHPs are particularly valuable animal models of obesity and diabetes for studying disease pathogenesis, risk factors, comorbidities, and therapeutic interventions.