Real World Interstitial Glucose Profiles of a Large Cohort of Physically Active Men and Women.

The use of continuous glucose monitors (CGMs) in individuals living without diabetes is increasing. The purpose of this study was to profile various CGM metrics around nutritional intake, sleep and exercise in a large cohort of physically active men and women living without any known metabolic disease diagnosis to better understand the normative glycemic response to these common stimuli. A total of 12,504 physically active adults (age 40 ± 11 years, BMI 23.8 ± 3.6 kg/m2; 23% self-identified as women) wore a real-time CGM (Abbott Libre Sense Sport Glucose Biosensor, Abbott, USA) and used a smartphone application (Supersapiens Inc., Atlanta, GA, USA) to log meals, sleep and exercise activities. A total of >1 M exercise events and 274,344 meal events were analyzed. A majority of participants (85%) presented an overall (24 h) average glucose profile between 90 and 110 mg/dL, with the highest glucose levels associated with meals and exercise and the lowest glucose levels associated with sleep. Men had higher mean 24 h glucose levels than women (24 h-men: 100 ± 11 mg/dL, women: 96 ± 10 mg/dL). During exercise, the % time above >140 mg/dL was 10.3 ± 16.7%, while the % time <70 mg/dL was 11.9 ± 11.6%, with the remaining % within the so-called glycemic tight target range (70-140 mg/dL). Average glycemia was also lower for females during exercise and sleep events (p < 0.001). Overall, we see small differences in glucose trends during activity and sleep in females as compared to males and higher levels of both TAR and TBR when these active individuals are undertaking or competing in endurance exercise training and/or competitive events.

Human regular U-500 insulin via continuous subcutaneous insulin infusion versus multiple daily injections in adults with type 2 diabetes: The VIVID study.

AIM: To compare the safety and efficacy of U500-R delivered by a novel, specifically designed U500-R insulin pump with U-500R delivered by multiple daily injections (MDI). METHODS: The phase 3 VIVID study randomized people with type 2 diabetes to U-500R by continuous subcutaneous insulin infusion (CSII) or MDI. Participants (aged 18-85 years) had HbA1c ≥7.5% and ≤12.0% and a total daily dose of insulin >200 and ≤600 U/day. After a 2-week transition to three times daily injections of U-500R, participants were treated for 24 weeks with U-500R by CSII or MDI. Treatment arms were compared using mixed model repeated measures analysis. RESULTS: The study randomized 420 participants (CSII: 209, MDI: 211) with 365 completers. Mean changes from baseline were: HbA1c, -1.27% (-13.9 mmol/mol) with CSII and -0.85% (-9.3 mmol/mol) with MDI (difference - 0.42% [-4.6 mmol/mol], P <0.001); fasting plasma glucose, -33.9 mg/dL (-1.9 mmol/L) with CSII and 1.7 mg/dL (0.09 mmol/L) with MDI (difference - 35.6 mg/dL [-2.0 mmol/L], P <0.001); total daily dose, 2.8 U with CSII and 51.3 U with MDI (P < 0.001). Weight changes and rates of documented symptomatic and severe hypoglycaemia were similar between groups; the CSII group had a higher rate of nocturnal hypoglycaemia. CONCLUSIONS: In type 2 diabetes requiring high doses of insulin, both methods of U-500R delivery lowered HbA1c. However, the CSII group attained greater HbA1c reduction with significantly less insulin. Individualized dose titration will be important to balance glycaemic control with hypoglycaemia risk.

Glycemic Outcomes in Adults With Type 2 Diabetes Participating in a Continuous Glucose Monitor-Driven Virtual Diabetes Clinic: Prospective Trial.

BACKGROUND: The Onduo virtual diabetes clinic (VDC) for people with type 2 diabetes (T2D) combines a mobile app, remote personalized lifestyle coaching, connected devices, and live video consultations with board-certified endocrinologists for medication management and prescription of real-time continuous glucose monitoring (RT-CGM) devices for intermittent use. OBJECTIVE: This prospective single-arm study evaluated glycemic outcomes associated with participation in the Onduo VDC for 4 months. METHODS: Adults aged ≥18 years with T2D and a baseline glycated hemoglobin (HbA1c) of ≥8% to ≤12% were enrolled from 2 primary care centers from February 2019 to October 2019. Participants were asked to engage at ≥1 time per week with their care team and to participate in a telemedicine consultation with a clinic endocrinologist for diabetes medication review. Participants were asked to use a RT-CGM device and wear six 10-day sensors (total 60 days of sensor wear) intermittently over the course of 4 months. The primary outcome was change in HbA1c at 4 months from baseline. Other endpoints included change in weight and in RT-CGM glycemic metrics, including percent time <70, 70-180, 181-250, and >250 mg/dL. Changes in blood pressure and serum lipids at 4 months were also evaluated. RESULTS: Participants (n=55) were 57.3 (SD 11.6) years of age, body mass index 33.7 (SD 7.2), and 40% (22/55) female. HbA1c decreased significantly by 1.6% (SD 1%; P<.001). When stratified by baseline HbA1c of 8.0% to 9.0% (n=36) and >9.0% (n=19), HbA1c decreased by 1.2% (SD 0.6%; P<.001) and 2.4% (SD 1.3%; P<.001), respectively. Continuous glucose monitoring-measured (n=43) percent time in range (TIR) 70-180 mg/dL increased by 10.2% (SD 20.5%; P=.002), from 65.4% (SD 23.2%) to 75.5% (SD 22.7%), which was equivalent to a mean increase of 2.4 hours TIR per day. Percent time 181-250 mg/dL and >250 mg/dL decreased by 7.2% (SD 15.4; P=.005) and 3.0% (SD 9.4; P=.01), respectively. There was no change in percent time <70 mg/dL. Mean weight decreased by 9.0 lb (SD 10.4; P<.001). Significant improvements were also observed in systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, and triglycerides (P=.04 to P=<.001). CONCLUSIONS: Participants in the Onduo VDC experienced significant improvement in HbA1c, increased TIR, decreased time in hyperglycemia, and no increase in hypoglycemia at 4 months. Improvements in other metabolic health parameters including weight and blood pressure were also observed. In conclusion, the Onduo VDC has potential to support people with T2D and their clinicians between office visits by increasing access to specialty care and advanced diabetes technology including RT-CGM. TRIAL REGISTRATION: ClinicalTrials.gov NCT03865381; https://clinicaltrials.gov/ct2/show/NCT03865381.

Impact of Participation in a Virtual Diabetes Clinic on Diabetes-Related Distress in Individuals With Type 2 Diabetes.

The Onduo Virtual Diabetes Clinic is a telehealth program for people with type 2 diabetes that combines mobile app technology, remote personalized lifestyle coaching, connected blood glucose meters, real-time continuous glucose monitoring (rtCGM) devices, and clinical support from board-certified endocrinologists. This analysis evaluated change in diabetes distress among 228 program participants who reported moderate distress (score 2.0-2.9) or high distress (score ≥3.0) on the 17-item Diabetes Distress Scale (DDS17) at enrollment. Participants reported significant reductions in overall distress from 3.0 ± 0.8 at baseline to 2.5 ± 0.9 (P <0.001) at an average of 6 months of follow-up. Significant reductions in all DDS17 subscale scores were observed; most notable were reductions in the regimen-related and emotional distress subscales (-0.9 and -0.4, respectively; both P <0.001). Significantly greater reductions in overall distress (P = 0.012) and regimen-related distress (P <0.001) were reported by participants who were prescribed and used intermittent rtCGM (n = 77) versus nonusers (n = 151). Although the generalizability of these findings may be limited by the study's small sample size and potential for self-selection bias, these results do suggest that telemedicine programs such as the Onduo VDC could be a valuable tool for addressing the problem of diabetes-related distress.

A New Animal Model of Insulin-Glucose Dynamics in the Intraperitoneal Space Enhances Closed-Loop Control Performance.

Current artificial pancreas systems (AP) operate via subcutaneous (SC) glucose sensing and SC insulin delivery. Due to slow diffusion and transport dynamics across the interstitial space, even the most sophisticated control algorithms in on-body AP systems cannot react fast enough to maintain tight glycemic control under the effect of exogenous glucose disturbances caused by ingesting meals or performing physical activity. Recent efforts made towards the development of an implantable AP have explored the utility of insulin infusion in the intraperitoneal (IP) space: a region within the abdominal cavity where the insulin-glucose kinetics are observed to be much more rapid than the SC space. In this paper, a series of canine experiments are used to determine the dynamic association between IP insulin boluses and plasma glucose levels. Data from these experiments are employed to construct a new mathematical model and to formulate a closed-loop control strategy to be deployed on an implantable AP. The potential of the proposed controller is demonstrated via in-silico experiments on an FDA-accepted benchmark cohort: the proposed design significantly outperforms a previous controller designed using artificial data (time in clinically acceptable glucose range: 97.3±1.5% vs. 90.1±5.6%). Furthermore, the robustness of the proposed closed-loop system to delays and noise in the measurement signal (for example, when glucose is sensed subcutaneously) and deleterious glycemic changes (such as sudden glucose decline due to physical activity) is investigated. The proposed model based on experimental canine data leads to the generation of more effective control algorithms and is a promising step towards fully automated and implantable artificial pancreas systems.

Intraperitoneal insulin delivery provides superior glycaemic regulation to subcutaneous insulin delivery in model predictive control-based fully-automated artificial pancreas in patients with type 1 diabetes: a pilot study.

AIMS: To compare intraperitoneal (IP) to subcutaneous (SC) insulin delivery in an artificial pancreas (AP). RESEARCH DESIGN AND METHODS: Ten adults with type 1 diabetes participated in a non-randomized, non-blinded sequential AP study using the same SC glucose sensing and Zone Model Predictive Control (ZMPC) algorithm adjusted for insulin clearance. On first admission, subjects underwent closed-loop control with SC delivery of a fast-acting insulin analogue for 24 hours. Following implantation of a DiaPort IP insulin delivery system, the identical 24-hour trial was performed with IP regular insulin delivery. The clinical protocol included 3 unannounced meals with 70, 40 and 70 g carbohydrate, respectively. Primary endpoint was time spent with blood glucose (BG) in the range of 80 to 140 mg/dL (4.4-7.7 mmol/L). RESULTS: Percent of time spent within the 80 to 140 mg/dL range was significantly higher for IP delivery than for SC delivery: 39.8 ± 7.6 vs 25.6 ± 13.1 ( P = .03). Mean BG (mg/dL) and percent of time spent within the broader 70 to 180 mg/dL range were also significantly better for IP insulin: 151.0 ± 11.0 vs 190.0 ± 31.0 ( P = .004) and 65.7 ± 9.2 vs 43.9 ± 14.7 ( P = .001), respectively. Superiority of glucose control with IP insulin came from the reduced time spent in hyperglycaemia (>180 mg/dL: 32.4 ± 8.9 vs 53.5 ± 17.4, P = .014; >250 mg/dL: 5.9 ± 5.6 vs 23.0 ± 11.3, P = .0004). Higher daily doses of insulin (IU) were delivered with the IP route (43.7 ± 0.1 vs 32.3 ± 0.1, P < .001) with no increased percent time spent <70 mg/dL (IP: 2.5 ± 2.9 vs SC: 4.1 ± 5.3, P = .42). CONCLUSIONS: Glycaemic regulation with fully-automated AP delivering IP insulin was superior to that with SC insulin delivery. This pilot study provides proof-of-concept for an AP system combining a ZMPC algorithm with IP insulin delivery.

Design and in silico evaluation of an intraperitoneal-subcutaneous (IP-SC) artificial pancreas.

Prandial glucose regulation is a major challenge for the artificial pancreas using subcutaneous insulin (without a feedforward bolus) due to insulin's slow absorption-peak (50-60 min). Intraperitoneal insulin, with a fast absorption peak (20-25 min), has been suggested as an alternative to address these limitations. An artificial pancreas using intraperitoneal insulin was designed and evaluated on 100 in silico subjects and compared with two designs using subcutaneous insulin with and without a feedforward bolus, following the three meal (40-70 g-carbohydrates) evaluation protocol. The design using intraperitoneal insulin resulted in a significantly lower postprandial blood glucose peak (38 mg/dL) and longer time in the clinically accepted region (13%) compared to the design using subcutaneous insulin without a feedforward bolus and comparable results to a subcutaneous feedforward bolus design. This superior regulation with minimal user interaction may improve the quality of life for people with type 1 diabetes mellitus.

Early immune factors associated with the development of post-acute sequelae of SARS-CoV-2 infection in hospitalized and non-hospitalized individuals.

Background: Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to post-acute sequelae of SARS-CoV-2 (PASC) that can persist for weeks to years following initial viral infection. Clinical manifestations of PASC are heterogeneous and often involve multiple organs. While many hypotheses have been made on the mechanisms of PASC and its associated symptoms, the acute biological drivers of PASC are still unknown. Methods: We enrolled 494 patients with COVID-19 at their initial presentation to a hospital or clinic and followed them longitudinally to determine their development of PASC. From 341 patients, we conducted multi-omic profiling on peripheral blood samples collected shortly after study enrollment to investigate early immune signatures associated with the development of PASC. Results: During the first week of COVID-19, we observed a large number of differences in the immune profile of individuals who were hospitalized for COVID-19 compared to those individuals with COVID-19 who were not hospitalized. Differences between individuals who did or did not later develop PASC were, in comparison, more limited, but included significant differences in autoantibodies and in epigenetic and transcriptional signatures in double-negative 1 B cells, in particular. Conclusions: We found that early immune indicators of incident PASC were nuanced, with significant molecular signals manifesting predominantly in double-negative B cells, compared with the robust differences associated with hospitalization during acute COVID-19. The emerging acute differences in B cell phenotypes, especially in double-negative 1 B cells, in PASC patients highlight a potentially important role of these cells in the development of PASC.

Association between pre-exercise food ingestion timing and reactive hypoglycemia: Insights from a large database of continuous glucose monitoring data.

Using a large database of continuous glucose monitoring (CGM) data, this study aimed to gain insights into the association between pre-exercise food ingestion timing and reactive hypoglycemia. A group of 6,761 users self-reported 48,799 pre-exercise food ingestion events and logged minute-by-minute CGM, which was used to detect reactive hypoglycemia (<70 mg/dL) in the first 30 min of exercise. A linear and a non-linear binomial logistic regression model was used to investigate the association between food ingestion timing and the probability of experiencing reactive hypoglycemia. An analysis of variance was conducted to compare the predictive ability of the models. On average, reactive hypoglycemia was detected in 8.34 ± 3.04% of the total events, with <15% of individuals experiencing hypoglycemia in >20% of their events. The majority of the reactive hypoglycemia events were found with pre-exercise food timing between ∼30 and ∼90 min, with a peak at ∼60 min. The superior accuracy (62.05 vs 45.1%) and F-score (0.75 vs 0.59) of the non-linear vs the linear model were statistically superior (P < 0.0001). These results support the notion of an unfavourable 30-to-90 min pre-exercise food ingestion time window which can significantly impact the likelihood of reactive hypoglycemia in some individuals.

Large datasets of self-reported continuous glucose monitoring and food events are used here for the first time to get insights into reactive hypoglycemia, a condition often regarded as negative for endurance performance eventsUsing a binomial non-linear logistic regression model, the association between pre-exercise food ingestion timing and reactive hypoglycemia revealed the presence of an unfavourable window, when reactive hypoglycemia is more likely to occur.Results confirm an individual predisposition to reactive hypoglycemia and, for 8 in 100 individuals, the pre-exercise food ingestion timing can meaningfully impact the likelihood of experiencing reactive hypoglycemia.

Standard Patient History Can Be Augmented Using Ethnographic Foodlife Questions.

The relationship between what and how individuals eat and their overall and long-term health is non-controversial. However, for decades, food and nutrition discussions have often been highly medicalized. Given the significant impact of poor nutrition on health, broader discussions about food should be integrated into routine patient history taking. We advocate for an expansion of the current, standard approach to patient history taking in order to include questions regarding patients' 'foodlife' (total relationship to food) as a screening and baseline assessment tool for referrals. We propose that healthcare providers: (1) routinely engage with patients about their relationship to food, and (2) recognize that such dialogues extend beyond nutrition and lifestyle questions. Mirroring other recent revisions to medical history taking-such as exploring biopsychosocial risks-questions about food relationships and motivators of eating may be essential for optimal patient assessment and referrals. We draw on the novel tools of 'foodlife' ethnography (developed by co-author ethnographer J.J.L., and further refined in collaboration with the co-authors who contributed their clinical experiences as a former primary care physician (D.M.E.), registered dietitian (J.W.M.), and diabetologist (H.Z.)) to model a set of baseline questions for inclusion in routine clinical settings. Importantly, this broader cultural approach seeks to augment and enhance current food intake discussions used by registered dietitian nutritionists, endocrinologists, internists, and medical primary care providers for better baseline assessments and referrals. By bringing the significance of food into the domain of routine medical interviewing practices by a range of health professionals, we theorize that this approach can set a strong foundation of trust between patients and healthcare professionals, underscoring food's vital role in patient-centered care.

Intraperitoneal Insulin Delivery: Evidence of a Physiological Route for Artificial Pancreas From Compartmental Modeling.

BACKGROUND: Intraperitoneal insulin delivery has proven to safely overcome a major limit of subcutaneous delivery-meal announcement-and has been able to optimize glycemic control in adults under controlled experimental conditions. In addition, intraperitoneal delivery avoids peripheral hyperinsulinemia resulting from the subcutaneous route and restores a physiological liver gradient. METHODS: Relying on a unique data set of intraperitoneal closed-loop insulin delivery obtained with a Model Predictive Controller (MPC), we develop a compartmental model of intraperitoneal insulin kinetics, which, once included in the UVa/Padova T1D simulator, will facilitate the investigation of various control strategies, for example, the simpler Proportional Integral Derivative controller versus MPC. RESULTS: Intraperitoneal insulin kinetics can be described with a 2-compartment model including liver and plasma. CONCLUSION: Intraperitoneal insulin transit is fast enough to render irrelevant the addition of a peritoneal compartment, proving the peritoneum being a virtual-not actual-transit space for insulin delivery.

Distinct temporal trajectories and risk factors for Post-acute sequelae of SARS-CoV-2 infection.

Background: The understanding of Post-acute sequelae of SARS-CoV-2 infection (PASC) can be improved by longitudinal assessment of symptoms encompassing the acute illness period. To gain insight into the various disease trajectories of PASC, we assessed symptom evolution and clinical factors associated with the development of PASC over 3 months, starting with the acute illness period. Methods: We conducted a prospective cohort study to identify parameters associated with PASC. We performed cluster and case control analyses of clinical data, including symptomatology collected over 3 months following infection. Results: We identified three phenotypic clusters associated with PASC that could be characterized as remittent, persistent, or incident based on the 3-month change in symptom number compared to study entry: remittent (median; min, max: -4; -17, 3), persistent (-2; -14, 7), or incident (4.5; -5, 17) (p = 0.041 remittent vs. persistent, p < 0.001 remittent vs. incident, p < 0.001 persistent vs. incident). Despite younger age and lower hospitalization rates, the incident phenotype had a greater number of symptoms (15; 8, 24) and a higher proportion of participants with PASC (63.2%) than the persistent (6; 2, 9 and 52.2%) or remittent clusters (1; 0, 6 and 18.7%). Systemic corticosteroid administration during acute infection was also associated with PASC at 3 months [OR (95% CI): 2.23 (1.14, 4.36)]. Conclusion: An incident disease phenotype characterized by symptoms that were absent during acute illness and the observed association with high dose steroids during acute illness have potential critical implications for preventing PASC.

Insulin pumps in pregnancy: using technology to achieve normoglycemia in women with diabetes.

Poorly controlled diabetes before conception and during pregnancy among women with pre-existing diabetes can cause major birth defects and spontaneous abortions, as wells as abnormal fetal growth and development including an offspring who is small or large for gestational age, or predisposed to obesity, type 2 diabetes, and metabolic syndrome in his/her lifetime. Conversely, for a woman with pre-existing diabetes, optimizing blood glucose levels before and during early pregnancy can reduce these risks dramatically. As insulin pump technology has evolved, continuous subcutaneous insulin infusion has become a safe and reliable method for treating diabetes during pregnancy. Although pump therapy is often preferred by patients and some experts, insulin pumps have not yet been shown to be superior to multiple daily injections of insulin during pregnancy. In this review of the literature we focus on the use of insulin pumps in the management of diabetes in pregnancy.

Medication Optimization Among People With Type 2 Diabetes Participating in a Continuous Glucose Monitoring-Driven Virtual Care Program: Prospective Study.

BACKGROUND: The Onduo virtual care program for people with type 2 diabetes (T2D) includes a mobile app, remote lifestyle coaching, connected devices, and telemedicine consultations with endocrinologists for medication management and prescription of real-time continuous glucose monitoring (RT-CGM) devices. In a previously described 4-month prospective study of this program, adults with T2D and baseline glycated hemoglobin (HbA1c) ≥8.0% to ≤12.0% experienced a mean HbA1c decrease of 1.6% with no significant increase in hypoglycemia. OBJECTIVE: The objective of this analysis was to evaluate medication optimization and management in the 4-month prospective T2D study. METHODS: Study participants received at least 1 telemedicine consultation with an Onduo endocrinologist for diabetes medication management and used RT-CGM intermittently to guide therapy and dosing. Medication changes were analyzed. RESULTS: Of 55 participants, 48 (87%) had a medication change consisting of a dose change, addition, or discontinuation. Of these, 15 (31%) participants had a net increase in number of diabetes medication classes from baseline. Mean time to first medication change for these participants was 36 days. The percentage of participants taking a glucagon-like peptide-1 receptor agonist increased from 25% (12/48) to 56% (n=27), while the percentages of participants taking a sulfonylurea or dipeptidyl peptidase 4 inhibitor decreased from 56% (n=27) to 33% (n=16) and 17% (n=8) to 6% (n=3), respectively. Prescriptions of other antidiabetic medication classes including insulin did not change significantly. CONCLUSIONS: The Onduo virtual care program can play an important role in providing timely access to guideline-based diabetes management medications and technologies for people with T2D. TRIAL REGISTRATION: ClinicalTrials.gov NCT03865381; https://clinicaltrials.gov/ct2/show/NCT03865381.

Remote Application and Use of Real-Time Continuous Glucose Monitoring by Adults with Type 2 Diabetes in a Virtual Diabetes Clinic.

The Onduo Virtual Diabetes Clinic (VDC) for people with type 2 diabetes (T2D) combines a mobile app, remote lifestyle coaching, connected devices, and live video consultations with board-certified endocrinologists. Adults with T2D (n = 594) who were evaluated by a VDC endocrinologist, remotely prescribed and mailed a real-time continuous glucose monitoring (rtCGM) device and used ≥1 sensor completed a CGM satisfaction questionnaire. The CGM satisfaction score was 4.5 ± 0.8 out of 5. Most respondents (94.7%) agreed/strongly agreed that they were comfortable inserting the sensor remotely and that rtCGM use improved understanding of the impact of eating (97.0%), increased diabetes knowledge (95.7%), and helped improve diabetes control when not wearing the sensor (79.4%). HbA1c (n = 372) decreased from 7.7% ± 1.6% to 7.1% ± 1.2% (P < 0.001; 10.2 months). These data suggest that it is feasible to provide rtCGM directly to individuals with T2D through a VDC without in-office training. Intermittent use of rtCGM was well-received by adults with T2D and was associated with improvement in HbA1c.

A Virtual Type 2 Diabetes Clinic Using Continuous Glucose Monitoring and Endocrinology Visits.

The Onduo Virtual Diabetes Clinic (VDC) telehealth technology/care model for adults with type 2 diabetes (T2D) combines connected devices, remote lifestyle coaching, and clinical support with a mobile App. Key differentiating program features are the availability of live video consultations with board-certified endocrinologists for medication management and real-time continuous glucose monitor use for higher-risk participants. Preliminary data (n = 740) suggest that participation was associated with a significant improvement in HbA1c with up to 6 months follow-up in those not meeting treatment targets. HbA1c decreased by 2.3% ± 1.9%, 0.7% ± 1.0%, and 0.2% ± 0.8% across baseline categories of >9.0%, 8.0%-9.0% and 7.0% to <8.0%, respectively (all P < .001). These findings suggest that the VDC has potential to support individuals with T2D and their clinicians in diabetes management between office visits.

Continuous glucose monitoring during pregnancy.

Diabetes throughout gestation presents challenges that greatly influence maternal and fetal outcomes. Since the degree of maternal hyperglycemia is the most deterministic of these risks, glucose monitoring has become a fundamental tool in the management of diabetes in pregnancy. While most patients with diabetes are in need of improved glucose control, certain circumstances beg for more detailed glucose information than is available by conventional methods alone. In this article, we will review the state of diabetes during pregnancy and the serious outcomes that persist despite the overall improvement in glycemic control today. We will discuss the advantages of incorporating continuous glucose monitoring (CGM), specifically in the treatment of pregnancies complicated by diabetes. In addition to its clinical utility, CGM can advance our understanding and classification of normoglycemia during pregnancy. Demarcation of the normal glucose profile that is present during gestation better defines the therapeutic goals for women with diabetes and ultimately promotes success in pregnancy.

In silico evaluation platform for artificial pancreatic beta-cell development--a dynamic simulator for closed-loop control with hardware-in-the-loop.

BACKGROUND: A critical step in algorithm development for an artificial beta-cell is extensive in silico testing. Computer simulations usually involve only the controller software, leaving untested the hardware elements, including the critical communication interface between the controller and the glucose sensor and insulin pump. METHODS: An in silico simulation platform has been developed that uses all of the components of the clinical system. At the core is a comprehensive in silico population model that covers the variability of principal metabolic parameters observed in vivo, to replace the human subject, with the ability to use historical clinical data. A continuous glucose monitor, in this case either the Abbott Diabetes Care (Alameda, CA) FreeStyle Navigator or the DexCom (San Diego, CA) STS7, is supplied with a glucose signal provided by the simulator. The Insulet (Bedford, MA) OmniPod insulin pump is also interfaced with the simulator to provide insulin delivery data. These hardware elements are an integral part of the system under testing, which also includes the algorithm components. RESULTS: The system is unique in that it uses the same hardware components for simulations as are required in clinical trials, allowing for full-system level verification and validation. With a detailed mathematical model, a suite of patients can be simulated to reflect various conditions. Because all hardware is used, their related limitations are automatically included. CONCLUSIONS: A complete artificial beta-cell evaluation platform was realized with the flexibility to interface various algorithms and patient models, allowing for the systematic analysis of monitoring and control algorithms. The system facilitates a variety of tests and challenges to the software and the component devices, streamlining preclinical validation trials.

Bolus calculator: a review of four "smart" insulin pumps.

Abstract The use of continuous subcutaneous insulin infusion (CSII) pumps has been gaining popularity since 1979, when the first research report on insulin pumps was published. Insulin pumps-small medical devices that are programmed to infuse insulin through a catheter placed under the skin-are a replacement for multiple daily injections of insulin. They are currently being used by 375,000 people with type 1 diabetes, many of whom prefer CSII to multiple daily injections because of the increased flexibility of diet and exercise, increased convenience and precision when dosing, and better predictability of blood glucose levels that insulin pumps can provide when used correctly. Recent pump manufacturers have engineered a new feature called a bolus calculator, which calculates bolus insulin doses based on input from the pump wearer, which functions to help patients obtain optimum control over blood glucose levels. The bolus calculator takes into account the patient's current blood glucose, target blood glucose, amount of carbohydrate consumed, and other factors such as insulin sensitivity and insulin-to-carbohydrate ratio as well as duration of insulin action ("insulin on board"). Each pump company calculates insulin doses in a slightly different way. This article will review differences in bolus calculator recommendations between four insulin pumps, as well as errors that may occur when using bolus calculators. It will also include an in silico simulation of a meal followed by a snack using multiple insulin decay curves.

An improved PID switching control strategy for type 1 diabetes.

In order for an "artificial pancreas" to become a reality for ambulatory use, a practical closed-loop control strategy must be developed and validated. In this paper, an improved PID control strategy for blood glucose control is proposed and critically evaluated in silico using a physiologic model of Hovorka et al. [1]. The key features of the proposed control strategy are: 1) a switching strategy for initiating PID control after a meal and insulin bolus; 2) a novel time-varying setpoint trajectory; 3) noise and derivative filters to reduce sensitivity to sensor noise; and 4) a practical controller tuning strategy. Simulation results demonstrate that proposed control strategy compares favorably to alternatives for realistic conditions that include meal challenges, incorrect carbohydrate meal estimates, changes in insulin sensitivity, and measurement noise.