Optimal insulin pump dosing and postprandial glycemia following a pizza meal using the continuous glucose monitoring system

The Impact of Different Types of Rice and Cooking on Postprandial Glycemic Trends in Children with Type 1 Diabetes with or without Celiac Disease

The aims of this study were to evaluate: (i) the chemical and nutritional composition of rice before and after cooking and (ii) postprandial glycemic impacts in children and adolescents with type 1 diabetes (T1D) after eating two different types of rice (“Gigante Vercelli” white rice and “Artemide” black rice) or white rice cooked “risotto” style or boiled using an advanced hybrid closed loop (AHCL) system (Tandem Control-IQTM). General composition and spectrophotometric analyses of raw and cooked rice were performed. Eight T1D subjects (four males and four females, aged 11 ± 1.4 years), two with celiac disease (CD), using an AHCL system were enrolled. “Gigante Vercelli” white rice cooked as risotto or boiled and boiled “Artemide” rice were prepared by the same cook on two evenings. Continuous glucose monitoring metrics were evaluated for 12 h after meal consumption. Total dietary fiber was higher for both rice types after cooking compared with raw rice. Cooking as risotto increased polyphenols and antioxidants (p < 0.05) in both rice varieties, and total starch decreased after boiling (p < 0.05) in white rice. There was a significant peak in glycemia after consuming risotto and boiled white rice (p < 0.05), while the mean glycemic peak remained <180 mg/dL in individuals eating boiled Artemide rice. There were no significant differences in automatic basal or auto-bolus insulin deliveries by the AHCL according to different types of rice or cooking method. Our findings suggest that glycemic trends are impacted by the different chemical and nutritional profiles of rice but are nevertheless well controlled by AHCL systems.

Efficacy of insulin dosing algorithms for high-fat high-protein mixed meals to control postprandial glycemic excursions in people living with type 1 diabetes: A systematic review and meta-analysis

Optimizing postprandial blood glucose (PPG) levels after mixed meals that contain high fat and protein remains a challenge in the treatment of type 1 diabetes. This study evaluated the efficacy of different algorithms used for dosing insulin based on counting units of high fat and high protein (HFHP) meals with the current conventional method of counting carbohydrates alone to control PPG excursions. The MEDLINE, EMBASE, and Cochrane electronic databases were searched, with the analysis restricted to randomized control trials (RCTs). The primary outcome was the PPG (mean and standard deviation) at 240 min. The pooled final estimate was the mean difference (MD) of the PPGs at 240 min using random effect models to account for heterogeneity. In total, 15 studies were identified and included in the systemic review, of which 12 were RCTs, and three studies were non-randomized trials. The pooled MD of the PPG at 240 min was in favor of additional insulin doses in HFHP meals compared to the carbohydrate counting alone. The statistically significant results favored the combined bolus (30:70) that split over 2 h in insulin pump therapy with pooled MD of the PPG, 240 min of -24.65; 95% CI: -36.59, -8.41; and heterogeneity, 0%. Other statistically significant results favored the additional insulin added to insulin to carb ratio (ICR) of meal bolus (25-60% ICR) in multiple daily injections therapy with the pooled MD of PPG at 240 min, -21.71; 95% CI: -38.45, -4.73; and heterogeneity, 18%. Insulin treatment based on fat and protein content, in addition to carbohydrate counting, is more effective than the carbohydrate counting method alone; however, further research is warranted to determine the best equation for fat and protein counting, particularly in people with multiple daily injections.

Decreased Need for Correction Boluses with Universal Utilisation of Dual-Wave Boluses in Children with Type 1 Diabetes

Insulin pumps offer standard (SB), square and dual-wave boluses (DWB). Few recommendations exist on how to use these dosing options. Several studies suggest that the DWB is more effective for high-fat or high-carbohydrate meals. Our objective was to test whether time in range (TIR) improves in children with type 1 diabetes (T1D) using the universal utilization of the dual-wave boluses for all evening meals regardless of the composition of the meal. This was a 28-day long prospective randomized open-label single-center crossover study. Twenty-eight children with T1DM using a Medtronic 640G pump and continuous glucose monitoring system were randomly assigned to receive either DWB or SB for all meals starting from 6:00 p.m. based solely on the food carbohydrate count. DWB was set for 50/50% with the second part extended over 2 h. After two weeks patients switched into the alternative treatment arm. TIR (3.9−10 mmol/L), time below range (TBR) (<3.9 mmol/L) and time above range (TAR) (>10 mmol/L) and sensor glucose values were measured and compared between the groups. Twenty-four children aged 7−14 years completed the study according to the study protocol. There were no statistically significant differences in mean TIR (60.9% vs. 58.8%; p = 0.3), TBR (1.6% vs. 1.7%; p = 0.7) or TAR (37.5 vs. 39%; p = 0.5) between DWB and SB groups, respectively. Subjects in the DWB treatment arm administered significantly less correction boluses between 6 p.m. and 6 a.m. compared to those in the SB group (1.2 ± 0.8 vs. 1.7 ± 0.8, respectively; p < 0.01). DWB for evening meals in which insulin is calculated solely on the food carbohydrate content did not improve TIR compared to standard bolus in children with T1D. However, DWB enabled to use significantly less correction boluses to achieve euglycemia by the morning compared to the SB.

A New Meal Absorption Model for Artificial Pancreas Systems

BACKGROUND

Artificial pancreas (AP) systems reduce the treatment burden of Type 1 Diabetes by automatically regulating blood glucose (BG) levels. While many disturbances stand in the way of fully closed-loop (automated) control, unannounced meals remain the greatest challenge. Furthermore, different types of meals can have significantly different glucose responses, further increasing the uncertainty surrounding the meal.

METHODS

Effective attenuation of a meal requires quick and accurate insulin delivery because of slow insulin action relative to meal effects on BG. The proposed Variable Hump (VH) model adapts to meals of varying compositions by inferring both meal size and shape. To appropriately address the uncertainty of meal size, the model divides meal absorption into two disjoint regions: a region with coarse meal size predictions followed by a fine-grain region where predictions are fine-tuned by adapting to the meal shape.

RESULTS

Using gold-standard triple tracer meal data, the proposed VH model is compared to three simpler second-order response models. The proposed VH model increased model fit capacity by 22% and prediction accuracy by 12% relative to the next best models. A 47% increase in the accuracy of uncertainty predictions was also found. In a simple control scenario, the controller governed by the proposed VH model provided insulin just as fast or faster than the controller governed by the other models in four out of the six meals. While the controllers governed by the other models all delivered at least a 25% excess of insulin at their worst, the VH model controller only delivered 9% excess at its worst.

CONCLUSIONS

The VH Model performed best in accuracy metrics and succeeded over the other models in providing insulin quickly and accurately in a simple implementation. Use in an AP system may improve prediction accuracy and lead to better control around mealtimes.

For a high fat, high protein breakfast, preprandial administration of 125% of the insulin dose improves postprandial glycaemic excursions in people with type 1 diabetes using multiple daily injections: A cross-over trial

AIM

To determine the glycaemic impact of an increased insulin dose, split insulin dose and regular insulin for a high fat, high protein breakfast in people with type 1 diabetes using multiple daily injections (≥4/day).

METHODS

In this cross-over trial, participants received the same high fat, high protein breakfast (carbohydrate:30 g, fat:40 g, protein:50 g) for 4 days. Four different insulin strategies were randomly allocated and tested; 100% of the insulin-to-carbohydrate ratio (ICR) given in a single dose using aspart insulin (100Asp), 125% ICR given in a single dose using aspart (125Asp) or regular insulin (125Reg) and 125% ICR given in a split dose using aspart insulin (100:25Asp). Insulin was given 0.25 hr pre-meal and for 100:25Asp, also 1 hr post-meal. Postprandial sensor glucose was measured for 5 hr.

RESULTS

In all, 24 children and adults were participated. The 5-hr incremental area under the curves for 100Asp, 125Asp, 125Reg and 100:25Asp were 620 mmol/L.min [95% CI: 451,788], 341 mmol/L.min [169,512], 675 mmol/L.min [504,847] and 434 mmol/L.min [259,608], respectively. The 5-hr incremental area under the curve for 125Asp was significantly lower than for 100Asp (p = 0.016) and for 125Reg (p = 0.002). There was one episode of hypoglycaemia in 125Reg.

CONCLUSIONS

For a high fat, high protein breakfast, giving 125% ICR preprandially, using aspart insulin significantly improved postprandial glycaemia without hypoglycaemia. There was no additional glycaemic benefit from giving insulin in a split dose (100:25%) or replacing aspart with regular insulin.

Insulin pump dosing strategies for meals varying in fat, protein or glycaemic index or grazing-style meals in type 1 diabetes: A systematic review

BACKGROUND

Nutritional composition and food patterns influence postprandial glycaemia in type 1 diabetes (T1D). For optimal glycaemic control, insulin dose and delivery pattern must be matched accordingly. This systematic review aimed to compare insulin dosing strategies for meals varying in fat, protein and glycaemic index (GI), and prolonged meals in T1D.

METHODS

Studies in adults and/or children with T1D on insulin pump therapy comparing the glycaemic effects of different insulin pump bolus types for these meal types were identified from biomedical databases (MEDLINE, PREMEDLINE, Embase, CINAHL and Cochrane Central Register of Controlled Trials; March 1995-April 2020) and systematically reviewed.

RESULTS

All eleven publications investigating high-fat meals (234 participants) and all seven studies investigating high-protein meals (129 participants) showed a dual-wave bolus was superior. Additional insulin further improved postprandial glycaemia, although increasing risk of hypoglycaemia in 5 of 14 studies. One study investigating GI found a dual-wave bolus reduced postprandial glycaemia and risk of hypoglycaemia. No studies were identified for grazing/degustation-style meals. Due to heterogeneity, meta-analysis was not possible.

CONCLUSION

Dual-wave boluses improve postprandial glycaemia in high-fat, high-protein and low-GI meals. Further research is needed to identify optimal bolus delivery split, duration and optimal total dose adjustment.

Demystifying the Pizza Bolus: The Effect of Dough Fermentation on Glycemic Response-A Sensor-Augmented Pump Intervention Trial in Children with Type 1 Diabetes Mellitus

Background: Glycemia following pizza consumption is typically managed with a dual-wave insulin bolus. This study evaluated the effect of a simple bolus on glycemia following consumption of traditionally prepared pizzas with long (24 h) or short (8 h) dough fermentation periods. Research Design and Methods: On two separate evenings, children with type 1 diabetes (n = 38) receiving sensor-integrated pump therapy consumed traditionally prepared pizza with either short (pizza A) or long (pizza B) dough fermentation, and blood glucose was monitored over 11 h. A simple insulin bolus was administered 15 min preprandially. The carbohydrate and amino acid contents of the two types of pizza were analyzed by liquid chromatography and high-resolution mass spectrometry (LC-HRMS). Results: The mean (±standard deviation) time in range 3.9-10.0 mmol/L was 73.2% ± 23.2%, and 50.8% ± 26.7% of glucose measurements were within the range 3.9-7.8 mmol/L. However, during the 2 h after bolus administration, the mean time in range 3.9-7.8 mmol/L was significantly greater with pizza B than with pizza A (73.3% ± 31.5% vs. 51.8% ± 37.4%, respectively, P = 0.009), and the time in hyperglycemia (>10 mmol/L) was significantly shorter (mean percentage 6.1% ± 19.0% vs. 17.7% ± 29.8%, respectively, P = 0.019). LC-HRMS analysis showed that long fermentation was associated with a lower carbohydrate content in the pizza, and a higher amino acid content. Conclusions: Glycemia following consumption of traditionally prepared pizza can be managed using a simple bolus 15 min before eating. Glycemic control can be further improved by increasing the dough fermentation time. Study registration: NCT03748251, Clinicaltrials.gov.

[Insulin pump therapy in children, adolescents and adults, guidelines (Update 2019)]

This position statement is based on current evidence available on the safety and benefits of continuous subcutaneous insulin infusion therapy (CSII, pump therapy) in diabetes with an emphasis on the effects of CSII on glycemic control, hypoglycaemia rates, occurrence of ketoacidosis, quality of life and the use of insulin pump therapy in pregnancy. The current article represents the recommendations of the Austrian Diabetes Association for the clinical praxis of insulin pump treatment in children, adolescents and adults.

Use of fast-acting insulin aspart in insulin pump therapy in clinical practice

Fast-acting insulin aspart (faster aspart) is a novel formulation of insulin aspart (IAsp) containing the additional excipients niacinamide and L-arginine. The improved pharmacological profile and greater early glucose-lowering action of faster aspart compared with IAsp suggests that faster aspart may be advantageous for people with diabetes using continuous subcutaneous insulin infusion (CSII). The recent onset 5 trial was the first to evaluate the efficacy and safety of an ultra-fast-acting insulin in CSII therapy in a large number of participants with type 1 diabetes (T1D). Non-inferiority of faster aspart to IAsp in terms of change from baseline in HbA1c was confirmed, with an estimated treatment difference (ETD) of 0.09% (95% CI, 0.01; 0.17; P < 0.001 for non-inferiority [0.4% margin]). Faster aspart was superior to IAsp in terms of change from baseline in 1-hour post-prandial glucose (PPG) increment after a meal test (ETD [95% CI], -0.91 mmol/L [-1.43; -0.39]; P = 0.001), with statistically significant improvements also at 30 minutes and 2 hours. The overall rate of severe or blood glucose-confirmed hypoglycaemia was not statistically significantly different between treatments, with an estimated rate ratio of 1.00 (95% CI, 0.85; 1.16). A numerical imbalance in severe hypoglycaemic episodes between faster aspart and IAsp was seen in the treatment (21 vs 7) and the 4-week run-in periods (4 vs 0). Experience from clinical practice indicates that all pump settings should be reviewed when initiating faster aspart with CSII, and that the use of continuous glucose monitoring or flash glucose monitoring, along with a good understanding of meal content and bolus type, may also facilitate optimal use. This review summarizes the available clinical evidence for faster aspart administered via CSII and highlights practical considerations based on clinical experience that may help healthcare providers and individuals with T1D successfully initiate and adjust faster aspart with CSII.

Glycemic Index, Extended Bolusing, and Diabetes Education in Insulin Pump Therapy (GLIDE: A Pilot Study)

Background: There is no published evidence on whether advanced bolus education affects outcomes in insulin pump-treated type 1 diabetes. We assess the feasibility of delivering a clinical education program on rates of digestion and bolusing, and to assess its preliminary impact. Methods: An interactive education session on glycemic index (GI), extended bolusing, and superbolusing was developed and assessed in a nonrandomized single-arm study for 12 weeks. Insulin pump-treated participants with type 1 diabetes were recruited. Glucose outcomes were assessed by blinded continuous glucose monitoring after the consumption of high-fat and high-GI test meal. The primary outcome measure was 8-h glucose area under the curve (AUC) after high-fat meals, before and after intervention. Secondary outcomes included time spent in hypoglycemia, quality of life, treatment satisfaction, HbA1c, frequency of use of extended boluses, and postprandial AUC. Results: Eleven participants completed the study [mean (SD) age 42.3 (12.8) years, baseline HbA1c 57.3 (10.0) mmol/mol, duration of diabetes 19.5 (9.9) years]. AUC for glucose after test meals did not differ significantly after education except for in the first 2 h after the high-GI meal [precourse 83.1 (0.23-88.9), postcourse 5.38 (-16.2 to 50.8)]. Percentage time spent in hypoglycemia (<3.9 and <3.3 mmol/L) fell at week 12 compared with baseline [5.8 (IQR 2.1-8.3) % to 4.3 (IQR 2.1-5.4) %, P = 0.013, and 2.9 (IQR 1.2-3.9) % to 1.6 (IQR 0.7-2.4) %, P = 0.029, respectively]. Conclusion: Delivering an education program to support advanced boluses is feasible and may reduce exposure to hypoglycemia. A further trial is required to confirm the findings.

Is insulin pump therapy effective in Type 1 diabetes?

There continues to be uncertainty about the effectiveness in Type 1 diabetes of insulin pump therapy (continuous subcutaneous insulin infusion, CSII) vs. multiple daily insulin injections (MDI). This narrative review discusses the reasons for this uncertainty, summarizes the current evidence base for CSII and suggests some future research needs. There are difficulties in interpreting trials of CSII because effectiveness varies widely due to factors such as differing baseline control, suboptimal use of best CSII practices, and psychological factors, for example, high external locus of control, non-adherence and lack of motivation. Many summary meta-analyses are also misleading because of poor trial selection (e.g. short duration, obsolete pumps, low baseline rate of hypoglycaemia) and reliance on mean effect size for decision-making. Both MDI and CSII can achieve strict glycaemic control without hypoglycaemia in some people with Type 1 diabetes, especially those who are motivated and have undergone structured diabetes education, and with high levels of ongoing input from healthcare professionals. CSII is particularly effective in those people with Type 1 diabetes who have not achieved target HbA_1c levels without disabling hypoglycaemia using best attempts with MDI, and here there can be valuable and substantial improvement. Insulin pumps are safe, effective and accepted when used in newly diagnosed diabetes, particularly in children, where MDI may not be practicable. Future research needs include more studies on mortality associated with insulin pumps where registry data have suggested lower rates vs. MDI; and psychological strategies to improve non-adherence and suboptimal glycaemic outcomes on CSII.

A randomized comparison of three prandial insulin dosing algorithms for children and adolescents with Type 1 diabetes

AIM

To compare systematically the impact of two novel insulin-dosing algorithms (the Pankowska Equation and the Food Insulin Index) with carbohydrate counting on postprandial glucose excursions following a high fat and a high protein meal.

METHODS

A randomized, crossover trial at two Paediatric Diabetes centres was conducted. On each day, participants consumed a high protein or high fat meal with similar carbohydrate amounts. Insulin was delivered according to carbohydrate counting, the Pankowska Equation or the Food Insulin Index. Subjects fasted for 5 h following the test meal and physical activity was standardized. Postprandial glycaemia was measured for 300 min using continuous glucose monitoring.

RESULTS

33 children participated in the study. When compared to carbohydrate counting, the Pankowska Equation resulted in lower glycaemic excursion for 90-240 min after the high protein meal (p < 0.05) and lower peak glycaemic excursion (p < 0.05). The risk of hypoglycaemia was significantly lower for carbohydrate counting and the Food Insulin Index compared to the Pankowska Equation (OR 0.76 carbohydrate counting vs. the Pankowska Equation and 0.81 the Food Insulin Index vs. the Pankowska Equation). There was no significant difference in glycaemic excursions when carbohydrate counting was compared to the Food Insulin Index.

CONCLUSION

The Pankowska Equation resulted in reduced postprandial hyperglycaemia at the expense of an increase in hypoglycaemia. There were no significant differences when carbohydrate counting was compared to the Food Insulin Index. Further research is required to optimize prandial insulin dosing.

Comparison between preprandial vs. postprandial insulin aspart in patients with type 1 diabetes on insulin pump and real-time continuous glucose monitoring

BACKGROUND

The objective was to compare glycemic control between preprandial and postprandial bolus administration (15 min before [PRE] or immediately after the meal [POST]) in patients with type 1 diabetes using insulin pump and real-time continuous glucose monitoring.

METHODS

Between September 2015 and February 2016, a single-centre, open randomized, 2-way crossover study of patients on bolus insulin aspart administration was conducted during two 14-day periods and according to 2 administration regimen schedules (PRE/POST or POST/PRE). Inclusion criteria were as follows: patients with type 1 diabetes, ≥18 and ≤ 65 years old, treated with insulin aspart using a Medtronic® insulin pump and trained on functional insulin therapy. Patients were randomly assigned to either regimen schedule. At the beginning of each period, each patient was provided with a standardized high fat meal. Primary outcome was the area under the curve for interstitial glucose above 140 mg/dL per minute (AUC > 140 mg/dL/min) during each period. Secondary outcomes were time spent in hypo/eu/hyperglycemia, glycemic variability indices, and AUC during 4 hours after high fat meal calculated with continuous glucose monitoring data.

RESULTS

Twenty-two patients were included. Mean AUC > 140 mg/dL/min was statistically higher in patients on POST (43.70 mg/dL/min; 95%CI: 34.08 to 53.31) versus PRE insulin aspart regimen (37.24 mg/dL/min 95%CI: 27.63 to 46.85) (P = 0.03). Mean interstitial glycemia and glycemic variability indices were also increased (P < 0.05) on POST regimen. The mean AUC 4 hours after the high fat meal was higher on POST regimen but not statistically different (P = 0.06).

CONCLUSIONS

In our study, postprandial administration of insulin aspart appears to mildly increase glycemic excursion and glycemic variability.

Technology in the management of type 1 diabetes mellitus - current status and future prospects

Type 1 diabetes mellitus (T1DM) represents 5-10% of diabetes cases worldwide. The incidence of T1DM is increasing, and there is no immediate prospect of a cure. As such, lifelong management is required, the burden of which is being eased by novel treatment modalities, particularly from the field of diabetes technologies. Continuous glucose monitoring has become the standard of care and includes factory-calibrated subcutaneous glucose monitoring and long-term implantable glucose sensing. In addition, considerable progress has been made in technology-enabled glucose-responsive insulin delivery. The first hybrid insulin-only closed-loop system has been commercialized, and other closed-loop systems are under development, including dual-hormone glucose control systems. This Review focuses on well-established diabetes technologies, including glucose sensing, pen-based insulin delivery, data management and data analytics. We also cover insulin pump therapy, threshold-based suspend, predictive low-glucose suspend and single-hormone and dual-hormone closed-loop systems. Clinical practice recommendations for insulin pump therapy and continuous glucose monitoring are presented, and ongoing research and future prospects are highlighted. We conclude that the management of T1DM is improved by diabetes technology for the benefit of the majority of people with T1DM, their caregivers and guardians and health-care professionals treating patients with T1DM.

US Army Soldiers With Type 1 Diabetes Mellitus

US Army soldiers diagnosed with type 1 diabetes were previously considered unfit for duty. For highly motivated soldiers, current advanced technologies allow the possibility of not only retention on active duty, but military deployment. We present our experience at Fort Bragg, North Carolina, taking care of soldiers newly diagnosed with type 1 diabetes mellitus. Through intensive diabetes education, extensive military and physical training, optimization of diabetes technology, and remote real-time monitoring, soldiers are able to continue to serve their country in the most specialized roles.

Optimal prandial timing of bolus insulin in diabetes management: a review

The inability to achieve optimal diabetes glucose control in people with diabetes is multifactorial, but one contributor may be inadequate control of postprandial glucose. In patients treated with multiple daily injections of insulin, both the dose and timing of meal-related rapid-acting insulin are key factors in this. There are conflicting opinions and evidence on the optimal time to administer mealtime insulin. We performed a comprehensive literature search to review the published data, focusing on the use of rapid-acting insulin analogues in patients with Type 1 diabetes. Pharmacokinetic and pharmacodynamic studies of rapid-acting insulin analogues, together with postprandial glucose excursion data, suggest that administering these 15-20 min before food would provide optimal postprandial glucose control. Data from clinical studies involving people with Type 1 diabetes receiving structured meals and rapid-acting insulin analogues support this, showing a reduction in post-meal glucose levels of ~30% and less hypoglycaemia when meal insulin was taken 15-20 min before a meal compared with immediately before the meal. Importantly, there was also a greater risk of postprandial hypoglycaemia when patients took rapid-acting analogues after eating compared with before eating.

Rapid-acting and Regular Insulin are Equal for High Fat-Protein Meal in Individuals with Type 1 Diabetes Treated with Multiple Daily Injections

INTRODUCTION

The fat and protein content can impact late postprandial glycemia; therefore, prolonged insulin boluses for high-fat/-protein meals are recommended for patients with type 1 diabetes on insulin pump therapy. It is not clear how to translate these findings to multiple daily injection (MDI) therapy. We hypothesized that regular insulin with a slower onset and a longer duration of action might be advantageous for such meals.

METHODS

Twenty-five patients with well-controlled type 1 diabetes (mean HbA1c 6.8%, 51 mmol/mol, no episodes of hypoglycemia) on MDI therapy, aged 27.9 ± 4.3 years and well trained in flexible intensive insulin therapy, were given three test breakfasts with the same carbohydrate (CHO) content. The amount of fat and protein was low (LFP) or high (HFP). For LFP meals, patients received a rapid-acting insulin; for HFP meals, a rapid-acting or regular insulin was given in individual doses according to the CHO content and individual insulin-CHO ratios. Postprandial glycemia was determined by 6-h continuous glucose monitoring.

RESULTS

Acute postprandial glucose levels measured for 2 h were similar after LFP and two HFP meals (7.8 ± 2.0, 8.1 ± 2.1, 8.0 ± 1.9 mmol/l). Late postprandial glycemia measured from 2 to 6 h was significantly lower after the LFP meal (6.7 ± 1.8 mmol/l, p < 0.05) than after the HFP meals, but there was no difference between the rapid-acting or regular insulin on HFP days (8.6 ± 2.6 and 8.9 ± 2.8 mmol/l, NS).

CONCLUSION

The preliminary results of this study indicate no benefit to cover fat-protein meals with regular insulin in individuals with type 1 diabetes treated with MDI.

Optimizing the combination insulin bolus split for a high-fat, high-protein meal in children and adolescents using insulin pump therapy

AIMS

To determine the optimum combination bolus split to maintain postprandial glycaemia with a high-fat and high-protein meal in young people with Type 1 diabetes.

METHODS

A total of 19 young people (mean age 12.9 ± 6.7 years) participated in a randomized, repeated-measures trial comparing postprandial glycaemic control across six study conditions after a high-fat and high-protein meal. A standard bolus and five different combination boluses were delivered over 2 h in the following splits: 70/30 = 70% standard /30% extended bolus; 60/40=60% standard/40% extended bolus; 50/50=50% standard/50% extended bolus; 40/60=40% standard/60% extended bolus; and 30/70=30% standard/70% extended bolus. Insulin dose was determined using the participant's optimized insulin:carbohydrate ratio. Continuous glucose monitoring was used to assess glucose excursions for 6 h after the test meal.

RESULTS

Standard bolus and combination boluses 70/30 and 60/40 controlled the glucose excursion up to 120 min. From 240 to 300 min after the meal, the glucose area under the curve was significantly lower for combination bolus 30/70 compared with standard bolus (P=0.004).

CONCLUSIONS

High-fat and high-protein meals require a ≥60% insulin:carbohydrate ratio as a standard bolus to control the initial postprandial rise. Additional insulin at an insulin:carbohydrate ratio of up to 70% is needed in the extended bolus for a high fat and protein meal to prevent delayed hyperglycaemia.

Late to the Party: Importance of Dietary Fat and Protein in the Intensive Management of Type 1 Diabetes. A Case Report

Insulin dosing in type 1 diabetes (T1D) has been focused primarily on carbohydrate intake, but recent evidence highlights the importance of dietary fat and protein in glycemic excursions. Several methods have been developed to incorporate dietary fat and protein into insulin dose calculations, including fat–protein units (FPUs) that estimate insulin requirements based on ingested fat and protein, as well as extended combination insulin boluses. However, insulin dosing based on meal fat and protein content is challenging to incorporate into clinical practice.

We present the case of a 40-year-old man with T1D using continuous subcutaneous insulin infusions and continuous glucose monitoring. He followed a diet that restricted carbohydrate intake, with compensatory increases in dietary protein and fat. He had poor glycemic control with frequent postprandial hyperglycemia. He began incorporating FPUs into his insulin dosing calculations and used extended dual wave boluses to administer prandial insulin. Over the next 6 months he experienced a significant improvement in glycemic control.

Fat and protein have both been shown to cause delayed postprandial hyperglycemia, leading to poor glycemic control with carbohydrate-focused insulin dosing in our patient on a high-fat, high-protein diet. It is difficult to incorporate dietary fat and protein into insulin dosing in the clinical setting. However, our patient experienced an improvement in glycemic control with the application of FPUs and dual wave boluses in prandial insulin dosing, showing that methods such as these can be used successfully in T1D management.

Boluses in Insulin Therapy

Giving a bolus is one major part in multiple dose insulin therapy (MDI) along with basal insulin substitution. To adjust the bolus optimally, different factors like carbohydrate content and composition of the meal, correction factors, and timing have to be considered. Advances in technologies like bolus advisors can assist the patients but still there a several open questions and technical challenges regarding boluses. This commentary provides an opportunity to address several of the above-mentioned factors influencing the result of bolusing. It shall draw attention to those factors and address the current opportunities, for example, continuous subcutaneous insulin infusion (CSII), as well as the need for further studies which can help to improve diabetes insulin therapy by means of the correct use of boluses.

Optimized Mealtime Insulin Dosing for Fat and Protein in Type 1 Diabetes: Application of a Model-Based Approach to Derive Insulin Doses for Open-Loop Diabetes Management

OBJECTIVE

To determine insulin dose adjustments required for coverage of high-fat, high-protein (HFHP) meals in type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Ten adults with T1D received low-fat, low-protein (LFLP) and HFHP meals with identical carbohydrate content, covered with identical insulin doses. On subsequent occasions, subjects repeated the HFHP meal with an adaptive model-predictive insulin bolus until target postprandial glycemic control was achieved.

RESULTS

With the same insulin dose, the HFHP increased the glucose incremental area under the curve over twofold (13,320 ± 2,960 vs. 27,092 ± 1,709 mg/dL ⋅ min; P = 0.0013). To achieve target glucose control following the HFHP, 65% more insulin was required (range 17%-124%) with a 30%/70% split over 2.4 h.

CONCLUSIONS

This study demonstrates that insulin dose calculations need to consider meal composition in addition to carbohydrate content and provides the foundation for new insulin-dosing algorithms to cover meals of varying macronutrient composition.

Omitting late-night eating may cause hypoglycemia in "well controlled" basal insulin-treated type 2 diabetes

OBJECTIVE

To assess hypoglycemia caused by eating the last meal of the day earlier or its omission in "well controlled" type 2 diabetes mellitus patients treated with once-nightly basal insulin.

METHODS

Previously basal insulin-titrated subjects (n = 20) (fasting plasma glucose, FPG, <110 mg/dL and no self-reported hypoglycemia) underwent continuous glucose monitoring (CGM) during 3 consecutive eating conditions of 3 days each; (1) usual eating, (2) the last meal restricted to 18:00, and (3) 1 sequential meal omitted/day thereby creating a fasting day after transposing the 4-hour period after a meal with that when the meal was omitted. One 24-hour (00:00 to 00:00) period within each eating condition was selected for comparison.

RESULTS

The mean duration in all hypoglycemic ranges doubled (P = .0584 or greater) when the last meal was omitted or eaten at 18:09 ± 0:39 instead of 19:43 ± 1:01, the usual time for the subjects' undisturbed eating. The mean duration of hypoglycemia was greatest between 00:00 to 06:00 compared to the 3 other 6-hour periods of the day.

CONCLUSIONS

Increased hypoglycemia occurs when the subject's last meal is eaten earlier or omitted and may not be recognized because it occurs predominately during sleep. When titrating basal insulin from the morning FPG, considerations should be given to the effect of the last meal of the day and possible hypoglycemia between 00:00 and 06:00 to avoid excessive basal insulin treatment.

[Insulin pump therapy in children, adolescents and adults]

This position statement is based on the current evidence available on the safety and benefits of continuous subcutaneous insulin pump therapy (CSII) in diabetes with an emphasis on the effects of CSII on glycemic control, hypoglycaemia rates, occurrence of ketoacidosis, quality of life and the use of insulin pump therapy in pregnancy. The current article represents the recommendations of the Austrian Diabetes Association for the clinical praxis of insulin pump treatment in children, adolescents and adults.

The Role of Dietary Protein and Fat in Glycaemic Control in Type 1 Diabetes: Implications for Intensive Diabetes Management

A primary focus of the management of type 1 diabetes has been on matching prandial insulin therapy with carbohydrate amount consumed. However, even with the introduction of more flexible intensive insulin regimes, people with type 1 diabetes still struggle to achieve optimal glycaemic control. More recently, dietary fat and protein have been recognised as having a significant impact on postprandial blood glucose levels. Fat and protein independently increase the postprandial glucose excursions and together their effect is additive. This article reviews how the fat and protein in a meal impact the postprandial glycaemic response and discusses practical approaches to managing this in clinical practice. These insights have significant implications for patient education, mealtime insulin dose calculations and dosing strategies.

Impact of fat, protein, and glycemic index on postprandial glucose control in type 1 diabetes: implications for intensive diabetes management in the continuous glucose monitoring era

BACKGROUND

Continuous glucose monitoring highlights the complexity of postprandial glucose patterns present in type 1 diabetes and points to the limitations of current approaches to mealtime insulin dosing based primarily on carbohydrate counting.

METHODS

A systematic review of all relevant biomedical databases, including MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials, was conducted to identify research on the effects of dietary fat, protein, and glycemic index (GI) on acute postprandial glucose control in type 1 diabetes and prandial insulin dosing strategies for these dietary factors.

RESULTS

All studies examining the effect of fat (n = 7), protein (n = 7), and GI (n = 7) indicated that these dietary factors modify postprandial glycemia. Late postprandial hyperglycemia was the predominant effect of dietary fat; however, in some studies, glucose concentrations were reduced in the first 2-3 h, possibly due to delayed gastric emptying. Ten studies examining insulin bolus dose and delivery patterns required for high-fat and/or high-protein meals were identified. Because of methodological differences and limitations in experimental design, study findings were inconsistent regarding optimal bolus delivery pattern; however, the studies indicated that high-fat/protein meals require more insulin than lower-fat/protein meals with identical carbohydrate content.

CONCLUSIONS

These studies have important implications for clinical practice and patient education and point to the need for research focused on the development of new insulin dosing algorithms based on meal composition rather than on carbohydrate content alone.

Novel insulin delivery profiles for mixed meals for sensor-augmented pump and closed-loop artificial pancreas therapy for type 1 diabetes mellitus

Maintaining euglycemia for people with type 1 diabetes is highly challenging, and variations in glucose absorption rates with meal composition require meal type specific insulin delivery profiles for optimal blood glucose control. Traditional basal/bolus therapy is not fully optimized for meals of varied fat contents. Thus, regimens for low- and high-fat meals were developed to improve current insulin pump therapy. Simulations of meals with varied fat content demonstrably replicated published data. Subsequently, an insulin profile library with optimized delivery regimens under open and closed loop for various meal compositions was constructed using particle swarm optimization. Calculations showed that the optimal basal bolus insulin profiles for low-fat meals comprise a normal bolus or a short wave. The preferred delivery for high-fat meals is typically biphasic, but can extend to multiple phases depending on meal characteristics. Results also revealed that patients that are highly sensitive to insulin could benefit from biphasic deliveries. Preliminary investigations of the optimal closed-loop regimens also display bi- or multiphasic patterns for high-fat meals. The novel insulin delivery profiles present new waveforms that provide better control of postprandial glucose excursions than existing schemes. Furthermore, the proposed novel regimens are also more or similarly robust to uncertainties in meal parameter estimates, with the closed-loop schemes demonstrating superior performance and robustness.

Insulin pump therapy in youth with type 1 diabetes: toward closed-loop systems

INTRODUCTION

Insulin pump technology has advanced considerably over the past three decades, leading to more favorable metabolic control and less hypoglycemic events when compared with multiple daily injection therapy. The use of insulin pumps is increasing, particularly in children and adolescents with type 1 diabetes.

AREAS COVERED

This review outlines recent developments in insulin pump therapy from a pediatric perspective. 'Smart' pumps, sensor-augmented pump therapy and threshold-suspend feature of insulin pumps are reviewed in terms of efficacy, safety and psychosocial impact. The current status of closed-loop systems focusing on clinical outcomes is highlighted.

EXPERT OPINION

Closed-loop insulin delivery is gradually progressing from bench to the clinical practice. Longer and larger studies in home settings are needed to expand on short- to medium-term outpatient evaluations. Predictive low glucose management and overnight closed-loop delivery may be the next applications to be implemented in daily routine. Further challenges include improvements of control algorithms, sensor accuracy, duration of insulin action, integration and size of devices and connectivity and usability. Gradual improvements and increasing sophistication of closed-loop components lie on the path toward unsupervised hands-off fully closed-loop system.

Both dietary protein and fat increase postprandial glucose excursions in children with type 1 diabetes, and the effect is additive

OBJECTIVE

To determine the separate and combined effects of high-protein (HP) and high-fat (HF) meals, with the same carbohydrate content, on postprandial glycemia in children using intensive insulin therapy (IIT).

RESEARCH DESIGN AND METHODS

Thirty-three subjects aged 8-17 years were given 4 test breakfasts with the same carbohydrate amount but varying protein and fat quantities: low fat (LF)/low protein (LP), LF/HP, HF/LP, and HF/HP. LF and HF meals contained 4 g and 35 g fat. LP and HP meals contained 5 g and 40 g protein. An individually standardized insulin dose was given for each meal. Postprandial glycemia was assessed by 5-h continuous glucose monitoring.

RESULTS

Compared with the LF/LP meal, mean glucose excursions were greater from 180 min after the LF/HP meal (2.4 mmol/L [95% CI 1.1-3.7] vs. 0.5 mmol/L [-0.8 to 1.8]; P = 0.02) and from 210 min after the HF/LP meal (1.8 mmol/L [0.3-3.2] vs. -0.5 mmol/L [-1.9 to 0.8]; P = 0.01). The HF/HP meal resulted in higher glucose excursions from 180 min to 300 min (P < 0.04) compared with all other meals. There was a reduction in the risk of hypoglycemia after the HP meals (odds ratio 0.16 [95% CI 0.06-0.41]; P < 0.001).

CONCLUSIONS

Meals high in protein or fat increase glucose excursions in youth using IIT from 3 h to 5 h postmeal. Protein and fat have an additive impact on the delayed postprandial glycemic rise. Protein had a protective effect on the development of hypoglycemia.

Dietary fat acutely increases glucose concentrations and insulin requirements in patients with type 1 diabetes: implications for carbohydrate-based bolus dose calculation and intensive diabetes management

OBJECTIVE

Current guidelines for intensive treatment of type 1 diabetes base the mealtime insulin bolus calculation exclusively on carbohydrate counting. There is strong evidence that free fatty acids impair insulin sensitivity. We hypothesized that patients with type 1 diabetes would require more insulin coverage for higher-fat meals than lower-fat meals with identical carbohydrate content.

RESEARCH DESIGN AND METHODS

We used a crossover design comparing two 18-h periods of closed-loop glucose control after high-fat (HF) dinner compared with low-fat (LF) dinner. Each dinner had identical carbohydrate and protein content, but different fat content (60 vs. 10 g).

RESULTS

Seven patients with type 1 diabetes (age, 55 ± 12 years; A1C 7.2 ± 0.8%) successfully completed the protocol. HF dinner required more insulin than LF dinner (12.6 ± 1.9 units vs. 9.0 ± 1.3 units; P = 0.01) and, despite the additional insulin, caused more hyperglycemia (area under the curve >120 mg/dL = 16,967 ± 2,778 vs. 8,350 ± 1,907 mg/dL⋅min; P < 0001). Carbohydrate-to-insulin ratio for HF dinner was significantly lower (9 ± 2 vs. 13 ± 3 g/unit; P = 0.01). There were marked interindividual differences in the effect of dietary fat on insulin requirements (percent increase significantly correlated with daily insulin requirement; R(2) = 0.64; P = 0.03).

CONCLUSIONS

This evidence that dietary fat increases glucose levels and insulin requirements highlights the limitations of the current carbohydrate-based approach to bolus dose calculation. These findings point to the need for alternative insulin dosing algorithms for higher-fat meals and suggest that dietary fat intake is an important nutritional consideration for glycemic control in individuals with type 1 diabetes.

Should the amounts of fat and protein be taken into consideration to calculate the lunch prandial insulin bolus? Results from a randomized crossover trial

BACKGROUND

Concerning continuous subcutaneous insulin infusion (CSII), there are controversial results related to changes in glycemic response according to the meal composition and bolus design. Our aim is to determine whether the presence of protein and fat in a meal could involve a different postprandial glycemic response than that obtained with only carbohydrates (CHs).

SUBJECTS AND METHODS

This was a crossover, randomized clinical trial. Seventeen type 1 diabetes (T1D) patients on CSII wore a blinded continuous glucose monitoring system sensor for 3 days. They ingested two meals (meal 1 vs. meal 2) with the same CH content (50 g) but different fat (8.9 g vs. 37.4 g) and protein (3.3 g vs. 28.9 g) contents. A single-wave insulin bolus was used, and the interstitial glucose values were measured every 30 min for 3 h. We evaluated the different postprandial glycemic response between meal 1 and meal 2 by using mixed-effects models.

RESULTS

The postmeal glucose increase was 22 mg/dL for meal 1 and 31 mg/dL for meal 2. In univariate analysis, at different times not statistically significant differences in glucose levels between meals occurred. In mixed-model analysis, a time×meal interaction was found, indicating a different response between treatments along the time. However, most of the patients remained in the normoglycemic range (70-180 mg/dL) during the 3-h postmeal period (84.4% for meal 1 and 93.1% for meal 2).

CONCLUSIONS

The presence of balanced amounts of protein and fat determined a different glycemic response from that obtained with only CH up to 3 h after eating. The clinical relevance of this finding remains to be elucidated.

Benefit of supplementary fat plus protein counting as compared with conventional carbohydrate counting for insulin bolus calculation in children with pump therapy

OBJECTIVE

To investigate carbohydrate (CARB) and supplementary fat/protein (CFP) counting using normal and dual-wave bolus in pump therapy of children and young people with type 1 diabetes (T1D).

STUDY DESIGN AND METHODS

A randomized clinical trial was conducted in 42 patients (age 6-21 yr) with T1D for at least 1 yr (5.2 ± 3.1 yr, mean ± SD) and pump therapy for at least 3 months (3.3 ± 1.8 yr). Standardized test meals (pizza-salami; 50% carbohydrate, 34% fat, 16% protein; corresponding to 33% of age-adjusted daily energy requirement) were given at lunch time on four different days with normal and dual-wave bolus using CARB and CFP counting in a randomized sequence. Sensor-augmented pumps were used for continuous glucose monitoring of 6-h postprandial glucose profiles. Intra-individual comparisons of glucose parameters [area under the curve (AUC) mg/dL × 6 h; average glucose, AV mg/dL] were performed.

RESULTS

Using CFP counting, 6-h postprandial glucose AUC (805 ± 261) and AV (137.8 ± 46.2) were significantly lower than AUC (926 ± 285) and AV (160.5 ± 51.9) by CARB counting (p < 0.001, each). CFP counting led to significantly lower postprandial glucose parameters independently from the kind of bolus (normal bolus: ΔAUC 169, p < 0.001; ΔAV 30.6, p < 0.001/dual-wave bolus: ΔAUC 73, p = 0.045, ΔAV 14.8, p = 0.033). Postprandial hypoglycemia episodes (<70 mg/dL) occurred more frequently in CFP than in CARB counting (35.7% vs. 9.5%, p < 0.001). No severe hypoglycemia was reported.

CONCLUSION

In patients with long-term T1D, meal-related insulin dosing based on carbohydrate plus fat/protein counting reduces the postprandial glucose levels (ClinicalTrials.gov NCT01400659).

Outpatient assessment of determinants of glucose excursions in adolescents with type 1 diabetes: proof of concept

Abstract Objective: Controlled inpatient studies on the effects of food, physical activity (PA), and insulin dosing on glucose excursions exist, but such outpatient data are limited. We report here outpatient data on glucose excursions and its key determinants over 5 days in 30 adolescents with type 1 diabetes (T1D) as a proof-of-principle pilot study.

SUBJECTS AND METHODS

Subjects (20 on insulin pumps, 10 receiving multiple daily injections; 15±2 years old; diabetes duration, 8±4 years; hemoglobin A1c, 8.1±1.0%) wore a continuous glucose monitor (CGM) and an accelerometer for 5 days. Subjects continued their existing insulin regimens, and time-stamped insulin dosing data were obtained from insulin pump downloads or insulin pen digital logs. Time-stamped cell phone photographs of food pre- and post-consumption and food logs were used to augment 24-h dietary recalls for Days 1 and 3. These variables were incorporated into regression models to predict glucose excursions at 1-4 h post-breakfast.

RESULTS

CGM data on both Days 1 and 3 were obtained in 57 of the possible 60 subject-days with an average of 125 daily CGM readings (out of a possible 144). PA and dietary recall data were obtained in 100% and 93% of subjects on Day 1 and 90% and 100% of subjects on Day 3, respectively. All of these variables influenced glucose excursions at 1-4 h after waking, and 56 of the 60 subject-days contributed to the modeling analysis.

CONCLUSIONS

Outpatient high-resolution time-stamped data on the main inputs of glucose variability in adolescents with T1D are feasible and can be modeled. Future applications include using these data for in silico modeling and for monitoring outpatient iterations of closed-loop studies, as well as to improve clinical advice regarding insulin dosing to match diet and PA behaviors.

Commentary on "Performance of a glucose meter with a built-in automated bolus calculator versus manual bolus calculation in insulin-using subjects"

Since the early 2000s, there has been an exponentially increasing development of new diabetes-applied technology, such as continuous glucose monitoring, bolus calculators, and "smart" pumps, with the expectation of partially overcoming clinical inertia and low patient compliance. However, its long-term efficacy in glucose control has not been unequivocally proven. In this issue of Journal of Diabetes Science and Technology, Sussman and colleagues evaluated a tool for the calculation of the prandial insulin dose. A total of 205 insulin-treated patients were asked to compute a bolus dose in two simulated conditions either manually or with the bolus calculator built into the FreeStyle InsuLinx meter, revealing the high frequency of wrong calculations when performed manually. Although the clinical impact of this study is limited, it highlights the potential implications of low diabetesrelated numeracy in poor glycemic control. Educational programs aiming to increase patients' empowerment and caregivers' knowledge are needed in order to get full benefit of the technology.

Management of diabetes mellitus: is the pump mightier than the pen?

Continuous subcutaneous insulin infusion (CSII, or insulin pump therapy) reduces HbA1c levels and hypoglycaemia in patients with type 1 diabetes mellitus (T1DM) compared with multiple daily insulin injections (MDI). The greatest reduction in HbA(1c) levels with CSII occurs in patients with the worst glycaemic control; therefore, the most appropriate and cost-effective use of CSII in adults with T1DM is in those who have continued, elevated HbA(1c) levels or disabling hypoglycaemic episodes with MDI (including the use of long-acting insulin analogues and structured patient education). The disadvantages of CSII include higher costs than MDI and the risk of ketosis in the event of pump failure. In children with T1DM, CSII may be used when MDI is considered impractical or inappropriate. Pumps are not generally recommended for patients with type 2 diabetes mellitus but may improve control in some subgroups. A new generation of smaller insulin infusion pumps with an integrated cannula, called patch pumps, could improve uptake of CSII in general. The important clinical question is not whether CSII is more efficacious than MDI in general adult T1DM, but whether CSII further improves glycaemic control when this control continues to be poor with MDI, and evidence exists that in most cases it does.

Does the fat-protein meal increase postprandial glucose level in type 1 diabetes patients on insulin pump: the conclusion of a randomized study

BACKGROUND

Our study examines the hypothesis that in addition to sugar starch-type diet, a fat-protein meal elevates postprandial glycemia as well, and it should be included in calculated prandial insulin dose accordingly. The goal was to determine the impact of the inclusion of fat-protein nutrients in the general algorithm for the mealtime insulin dose calculator on 6-h postprandial glycemia.

SUBJECTS AND METHODS

Of 26 screened type 1 diabetes patients using an insulin pump, 24 were randomly assigned to an experimental Group A and to a control Group B. Group A received dual-wave insulin boluses for their pizza dinner, consisting of 45 g/180 kcal of carbohydrates and 400 kcal from fat-protein where the insulin dose was calculated using the following algorithm: n Carbohydrate Units×ICR+n Fat-Protein Units×ICR/6 h (standard+extended insulin boluses), where ICR represents the insulin-to-carbohydrate ratio. For the control Group B, the algorithm used was n Carbohydrate Units×ICR. The glucose, C-peptide, and glucagon concentrations were evaluated before the meal and at 30, 60, 120, 240, and 360 min postprandial.

RESULTS

There were no statistically significant differences involving patients' metabolic control, C-peptide, glucagon secretion, or duration of diabetes between Group A and B. In Group A the significant glucose increment occurred at 120-360 min, with its maximum at 240 min: 60.2 versus -3.0 mg/dL (P=0.04), respectively. There were no significant differences in glucagon and C-peptide concentrations postprandial.

CONCLUSIONS

A mixed meal effectively elevates postprandial glycemia after 4-6 h. Dual-wave insulin bolus, in which insulin is calculated for both the carbohydrates and fat proteins, is effective in controlling postprandial glycemia.

The effect of insulin feedback on closed loop glucose control

CONTEXT

Initial studies of closed-loop proportional integral derivative control in individuals with type 1 diabetes showed good overnight performance, but with breakfast meal being the hardest to control and requiring supplemental carbohydrate to prevent hypoglycemia.

OBJECTIVE

The aim of this study was to assess the ability of insulin feedback to improve the breakfast-meal profile.

DESIGN AND SETTING

We performed a single center study with closed-loop control over approximately 30 h at an inpatient clinical research facility.

PATIENTS

Eight adult subjects with previously diagnosed type 1 diabetes participated.

INTERVENTION

Subjects received closed-loop insulin delivery with supplemental carbohydrate as needed.

MAIN OUTCOME MEASURES

Outcome measures were plasma insulin concentration, model-predicted plasma insulin concentration, 2-h postprandial and 3- to 4-h glucose rate-of-change following breakfast after 1 d of closed-loop control, and the need for supplemental carbohydrate in response to nadir hypoglycemia.

RESULTS

Plasma insulin levels during closed loop were well correlated with model predictions (R = 0.86). Fasting glucose after 1 d of closed loop was not different from nighttime target (118 ± 9 vs. 110 mg/dl; P = 0.38). Two-hour postbreakfast glucose was 132 ± 16 mg/dl with stable values 3-4 h after the meal (0.03792 ± 0.0884 mg/dl · min, not different from 0; P = 0.68) and at target (97 ± 6 mg/dl, not different from 90; P = 0.28). Three subjects required supplemental carbohydrates after breakfast on d 2 of closed loop.

CONCLUSIONS/INTERPRETATION

Insulin feedback can be implemented using a model estimate of concentration. Proportional integral derivative control with insulin feedback can achieve a desired breakfast response but still requires supplemental carbohydrate to be delivered in some instances. Studies assessing more optimal control configurations and safeguards need to be conducted.

Basal insulin requirement is ~30% of the total daily insulin dose in type 1 diabetic patients who use the insulin pump

OBJECTIVE

To investigate the basal insulin requirement in total daily insulin dose in Japanese type 1 diabetic patients who use the insulin pump.

RESEARCH DESIGN AND METHODS

The basal insulin requirement in 35 type 1 diabetic patients without detectable C-peptide using the insulin pump (Paradigm 712) was investigated during 2-3 weeks of hospitalization. The patients were served diabetic diets of 25-30 kcal/kg ideal body weight. Each meal omission was done to confirm stable blood glucose levels within 30 mg/dL variance until the next meal. Target blood glucose level was set at 100 mg/dL before each meal and 150 mg/dL at 2 h after each meal.

RESULTS

Total daily insulin dose was 31.6 ± 8.5 units, and total basal insulin requirement was 8.7 ± 2.9 units, which was 27.7 ± 6.9% of the total daily dose.

CONCLUSIONS

Basal insulin requirement is ~30% of the total daily dose in Japanese type 1 diabetic patients who use the insulin pump.

Lowering postprandial glycemia in children with type 1 diabetes after Italian pizza "margherita" (TyBoDi2 Study)

BACKGROUND

Continuous subcutaneous insulin infusion is considered a safe and effective way to administer insulin in pediatric patients with type 1 diabetes, but achieving satisfactory and stable glycemic control is difficult. Several factors contribute to control, including fine-tuning the basal infusion rate and bolus type and timing. We evaluated the most effective type and timing of a pump-delivered, preprandial bolus in children with type 1 diabetes for a pizza "margherita" meal.

SUBJECTS AND METHODS

We assessed the response of 38 children with type 1 diabetes to a meal based on pizza "margherita" (with mozzarella cheese and tomato sauce) after different types and timings of a bolus dose.

RESULTS

The glucose levels for 6 h after the meal were lower (i.e., closer to the therapeutic target of <140 mg/dL) when the bolus doses were administered as a simple bolus 15 min before the meal (area under the curve [AUC] 0-6 h, 6.9 ± 14.9 mg/dL/min) versus a simple bolus administered immediately before the meal (AUC 0-6 h, 4.2 ± 25.9 mg/dL/min) (P = not significant) versus a double-wave bolus 30/70 extended over a 6-h period administered 15 min before the meal (AUC 0-6 h, 1.9 ± 21.3 mg/dL/min) (P = not significant) versus a double-wave bolus 30/70 extended over a 6-h period administered immediately before the meal (AUC 0-6 h, 13.3 ± 15.6 mg/dL/min) (P = 0.01).

CONCLUSIONS

In the case of a pizza "margherita," our data support the injection of the simple bolus 15 min before a meal, rather than immediately before or delivered as a double-wave bolus, to control the glycemic rise usually observed.

The dual-wave bolus feature in type 1 diabetes adult users of insulin pumps

One of the attributes of CSII (continuous subcutaneous insulin infusion) is its ability to tailor prandial insulin delivery to the composition of a meal and anticipated glycemic effects. The dual-wave bolus (DWB) is a tool implemented in contemporary insulin pumps that delivers a combination of an instant insulin bolus followed by a square bolus (SB) infused over several hours. We assessed the effectiveness of DWB in 56 adult patients with type 1 diabetes (T1DM) who were on continuous subcutaneous insulin infusion via insulin pump for at least 2 years. We divided patients into frequent (DWB+, n = 32) and infrequent (DWB-, n = 24) DWB users (>20% vs. <20% of daily bolus dose delivered as SB). CSII implementation resulted in a decrease of adjusted HbA1c level by 0.80% (95% CI 0.67-0.93, P < 0.0001) and adjusted mean glycemia by 18.4 mg/dl (95% CI 15.3-21.4, P < 0.0001) in the whole cohort within the first year of observation. It was sustained in the second year, but without further improvement. Frequent DWB use was associated with male sex (59% vs. 17%, p = 0.001) and shorter duration of T1DM (3.4 vs. 11.3 yrs, p < 0.0001), but not with patients' age (25.7 vs. 27.0 years, P = 0.6). DWB+ patients improved their HbA1c by 0.45% more (95% CI 0.20-0.71, P = 0.0009) than DWB- individuals. In conclusion, DWB might be a tool potentially helping to improve glycemic control in T1DM adult users of insulin pumps. Male patients and those with a shorter duration of diabetes seem to use it more willingly.

Practical aspects and considerations when switching between continuous subcutaneous insulin infusion and multiple daily injections

Insulin pump therapy is considered the gold standard for insulin management in patients requiring full physiologic insulin replacement. Compared to traditional delivery of short- and long-acting insulin preparations by multiple daily insulin injections, delivery of insulin via continuous subcutaneous infusion brings with it several advantages, which in the past have translated into better glycemic control and treatment satisfaction. Delivery of insulin via pump reduces the number needle insertions (from four or five per day to once every 2-3 days), allows for greater flexibility of insulin delivery with regard to both the basal and prandial component, facilitates portability of the insulin preparation, and allows for more accurate dosing. Continuous subcutaneous insulin infusion does have some drawbacks, including a greater risk of inadvertent insulin non-delivery, greater costs of therapy, and the need to be "tethered" with some systems that might be considered "burdensome" or even undesirable to some patients. For the most part patients who initiate insulin pump therapy are satisfied and continue using the technology, but there might be instances that arise that require the re-introduction of insulin delivery by pen or syringe. This article will review some of the reasons and strategies for switching from one mode of delivery to the other.