Amy T. Steffen

Persistence of Benefits of Continuous Subcutaneous Insulin Infusion in Very Young Children With Type 1 Diabetes: A Follow-up Report

Objective. Use of continuous subcutaneous insulin infusion (CSII) has increased dramatically in recent years, and pump therapy has been shown to be a safe and effective alternative to multiple daily injections in adults and older pediatric patients with type 1 diabetes. Its use in very young children, however, has been limited, although this group might be expected to benefit the most from CSII. The objective of this study was to analyze the CSII efficacy and safety data in very young children with type 1 diabetes from our Diabetes Clinic database. Methods. Glycosylated hemoglobin (HbA1c), severe hypoglycemia (SH), and ketoacidosis (DKA) in the year before CSII were compared with corresponding values during pump treatment in all children who started CSII before age 7. Results. Sixty-five children (mean age: 4.5 y at CSII initiation; range: 1.4–6.9 years; 28 girls; 3 black, 1 Hispanic) were analyzed for >162 patient-years of follow-up. Mean HbA1c (7.4 ± 1.0 prepump) decreased to 7.0 ± 0.9 after 12 months of CSII and continued to improve even after 4 years on CSII. The rate of SH was reduced by 53% (from 78 to 37/100 patient-years). Children who received daytime care from paid caregivers (n = 26) experienced significant reductions in HbA1c and hypoglycemia frequency. There were no episodes of DKA requiring emergency treatment in the year before CSII and 4 episodes (4 per 100 patient-years) after transition to pump. Conclusions. CSII is a durable and effective means of optimizing glycemic control in very young patients with type 1 diabetes and may be superior to multiple daily injections in minimizing the risk of severe hypoglycemia in this age group. Employment of paid caregivers does not preclude safe and effective use of CSII.

Is an automatic pump suspension feature safe for children with type 1 diabetes? An exploratory analysis with a closed-loop system.

OBJECTIVES It has been proposed that the first step towards a closed-loop artificial pancreas might be to use a continuous glucose sensor to automatically suspend the basal insulin delivery based on projected low sensor glucose values. METHODS We reviewed our recent experience with an artificial pancreas system, utilizing a proportional-integrative-derivative (PID) algorithm, in 17 adolescents with type 1 diabetes (T1D) to assess the safety and efficacy of this maneuver. RESULTS During 34 h of closed-loop automated insulin delivery, 18 pump suspensions > or =60 min (90 +/- 18 min) occurred in eight subjects. Sensor glucose levels fell from 159 +/- 42 mg/dL to a nadir of 72 +/- 13 mg/dL. Corresponding plasma glucose levels fell from 168 +/- 51 to 72 +/- 16 mg/dL, with values <60 mg/dL recorded in only four of the 18 events. CONCLUSIONS These data suggest that automatic pump suspension using the PID algorithm may be an effective means to prevent hypoglycemia in youth with T1D.

Effect of Age of Infusion Site and Type of Rapid-Acting Analog on Pharmacodynamic Parameters of Insulin Boluses in Youth With Type 1 Diabetes Receiving Insulin Pump Therapy

OBJECTIVE—The purpose of this study was to examine the effect of type of insulin analog and age of insertion site on the pharmacodynamic characteristics of a standard insulin bolus in youth with type 1 diabetes receiving insulin pump therapy. RESEARCH DESIGN AND METHODS—Seventeen insulin pump–treated adolescents with type 1 diabetes underwent two euglycemic clamp procedures after a 0.2 unit/kg bolus of either insulin aspart or lispro on day 1 and day 4 of insulin pump site insertion. The glucose infusion rate (GIR) required to maintain euglycemia was the primary pharmacodynamic measure. RESULTS—There were no statistically significant differences in any of the pharmacodynamic parameters between aspart and lispro during day 1 and day 4. However, when the two groups were combined, time to discontinuation of exogenous glucose infusion, and time to half-maximal onset and offset of insulin action were observed significantly earlier during day 4 compared with day 1 (P = 0.03–0.0004), but the overall area under the GIR curve was similar on day 1 and day 4. CONCLUSIONS—With both insulin aspart and lispro, there is an earlier peak and shorter duration of action with increasing duration of infusion site use, but overall insulin action is not affected.

Analysis of Continuous Glucose Monitoring Data from Non-Diabetic and Diabetic Children: A Tale of Two Algorithms

Use of the Medtronic MiniMed Continuous Glucose Monitoring System (CGMS) in non-diabetic children has revealed many low and high sensor glucose (SG) values, suggesting that the original analytical algorithm (Solutions 2.0) might be overreading glycemic excursions. A revised algorithm (Solutions 3.0) was introduced in 2001. Our aim was to compare analyses of the same sensor profiles using both programs. Twenty-five lean, non-diabetic subjects (mean age 14 +/- 4 years) underwent continuous glucose monitoring with CGMS for up to 72 h. Sensor tracings were analyzed with both algorithms and compared. Separate analyses were performed for nocturnal readings (12-6 a.m.). Mean SG values were similar (103 +/- 24 mg/dL for version 2.0 vs. 100 +/- 14 for version 3.0), but the distribution was significantly different: 13.8% of total SG were <70 mg/dL by version 2.0 versus 8.2% by version 3.0 (p < 0.001), and 7.7% of total SG were >150 mg/dL by version 2.0 versus 4.7% by version 3.0 (p = 0.02). Of nocturnal SG values, 25.8% were <70 mg/dL by version 2.0 compared with 17.9% by version 3.0, and 9.4% were >150 mg/dL by version 2.0 compared with 4.0% by version 3.0. In lean non-diabetic children, Solutions 2.0 identified significantly more hypoglycemia and hyperglycemia than Solutions 3.0. Similar analyses in 40 children with type 1 diabetes revealed no significant differences. Solutions 3.0 may be a more useful algorithm for preventing over-reading of low and high SG readings in non-diabetic children, whereas both algorithms give similar results in children with diabetes.

Acceleration of insulin pharmacodynamic profile by a novel insulin infusion site warming device.

Subcutaneously injected rapid‐acting insulin analogs do not replicate physiologic insulin action due to delays in their onset and peak action resulting in postprandial glucose excursions. The InsuPatch (IP) is a novel insulin infusion site warming device developed to accelerate insulin action by increasing blood flow to the area of insulin absorption. Thirteen adolescents with type 1 diabetes (T1D, mean age 14 ± 4 yr) were enrolled in this study to investigate the effect of the IP on the pharmacodynamics and pharmacokinetics of a 0.2 unit/kg bolus dose of aspart insulin using the euglycemic clamp technique.

Safety of Nighttime 2-Hour Suspension of Basal Insulin in Pump-Treated Type 1 Diabetes Even in the Absence of Low Glucose

OBJECTIVE An integrated sensor-augmented pump system has been introduced that interrupts basal insulin infusion for 2 h if patients fail to respond to low-glucose alarms. It has been suggested that such interruptions of basal insulin due to falsely low glucose levels detected by sensor could lead to diabetic ketoacidosis. We hypothesized that random suspension of basal insulin for 2 h in the overnight period would not lead to clinically important increases in blood β-hydroxybutyrate levels despite widely varying glucose values prior to the suspension. RESEARCH DESIGN AND METHODS Subjects measured blood glucose and blood β-hydroxybutyrate levels using a meter each night at 9:00 p.m., then fasted until the next morning. On control nights, the usual basal rates were continued; on experimental nights, the basal insulin infusion was reprogrammed for a 2-h zero basal rate at random times after 11:30 p.m. RESULTS In 17 type 1 diabetic subjects (mean age 24 ± 9 years, diabetes duration 14 ± 11 years, A1C level 7.3 ± 0.5% [56 mmol/mol]), blood glucose and blood β-hydroxybutyrate levels were similar at 9:00 p.m. on suspend nights (144 ± 63 mg/dL and 0.09 ± 0.07 mmol/L) and nonsuspend nights (151 ± 65 mg/dL and 0.08 ± 0.06 mmol/L) (P = 0.39 and P = 0.47, respectively). Fasting morning blood glucose levels increased after suspend nights compared with nonsuspend nights (191 ± 68 vs. 141 ± 75 mg/dL, P < 0.0001), and the frequency of fasting hypoglycemia decreased the morning following suspend nights (P < 0.0001). Morning blood β-hydroxybutyrate levels were slightly higher after suspension (0.13 ± 0.14 vs. 0.09 ± 0.11 mmol/L, P = 0.053), but the difference was not clinically important. CONCLUSIONS Systems that suspend basal insulin for 2 h are safe and do not lead to clinically significant ketonemia even if the blood glucose level is elevated at the time of the suspension.

Skin and Adhesive Issues With Continuous Glucose Monitors A Sticky Situation

Background: The purpose of this article is to describe challenges associated with successful use of continuous glucose monitoring (CGM) by young children with type 1 diabetes (T1D) and to detail the techniques and products used to improve the duration of sensor wear. Methods: The DirecNet Study Group conducted 2 studies in 169 children with T1D between the ages of 1 and 9 years who were instructed to wear a CGM device daily. Problems related to skin irritation and sensor adhesiveness in these young children presented challenges to daily use of the CGM. Study coordinators instituted a variety of techniques using commercially available products to attempt to overcome these problems. Results: Three primary factors that contributed to reduced CGM use were identified: the limited body surface area in smaller children, ambient temperature and humidity, as well as the type and duration of physical activity. Using supplemental products to minimize the impact of these factors resulted in improved adherence and reduced skin irritation. Conclusion: Achieving satisfactory adhesion of the CGM sensor and transmitter may involve finding the right supplemental product or combination of products through trial and error. Optimizing adhesion and minimizing skin irritation can significantly improve duration of use and tolerability of CGM devices by young children.

The renaissance of insulin pump treatment in childhood type 1 diabetes

Current goals for the treatment of children and adolescents with type 1 diabetes mellitus include achieving near-normal blood sugar levels, minimizing the risk of hypoglycemia, optimizing quality of life, and preventing or delaying long-term microvascular and macrovascular complications. Continuous subcutaneous insulin infusion (CSII), or insulin pump therapy, provides a treatment option that can assist in the attainment of all of these goals in all ages of children. In pediatric patients, CSII has been demonstrated to reduce both glycosylated hemoglobin levels and frequency of severe hypoglycemia, without sacrifices in safety, quality of life, or weight gain, particularly in conjunction with the use of new insulin analogs and improvements in pump technology. Clinical studies of safety and efficacy of CSII in children are reviewed, as well as criteria for patient selection and practical considerations using pump therapy in youth with T1DM.

Continuous subcutaneous insulin infusion (CSII) in children with type 1 diabetes

Recent studies have shown that continuous subcutaneous insulin infusion (CSII), or insulin pump therapy, provides a treatment option that can assist in the attainment of current goals of treatment in children and adolescents with type 1 diabetes (T1DM). In pediatric patients, CSII has been demonstrated to reduce both glycosylated hemoglobin levels and frequency of severe hypoglycemia, without sacrifices in safety, quality of life, or excessive weight gain, particularly in conjunction with the use of new insulin analogs and improvements in pump technology. Clinical studies of safety and efficacy of CSII in children are reviewed.

Case Study Contrasting Challenges of Insulin Pump Therapy in a Toddler and Adolescent With Type 1 Diabetes

Purpose To describe the challenges and outcomes of continuous subcutaneous insulin infusion (CSII) pump therapy in a toddler and adolescent with type 1 diabetes. Insight into patient-family aspects motivating pump use is provided. Methods Two cases treated at the Pediatric Diabetes Clinic at Yale University. Results Upon parental request, CSII was initiated to improve glycemic control in a 4-year-old boy (case 1) with unpredictable food intake. During 68 months of CSII therapy, hemoglobin A1C levels averaged 6.3% ± 0.6%. Severe hypoglycemic episodes ceased 36 months ago, and occasional postprandial hyperglycemia during early school years was corrected with school nurses’ reminders about premeal insulin bolus doses. Currently 9.5 years old, he independently manages all his insulin injections with parental assistance only to change the catheter site. Case 2 is a girl who was nearly 12 years of age when diagnosed with type 1 diabetes. Initially managed with daily injections, hypoglycemic episodes were interfering with her physically active lifestyle. At age 13 years, she elected CSII therapy, and glycemic control improved. Temporarily erratic in the immediate period pre- and postmenarche, metabolic control has since stabilized. At 15 years old, she successfully manages her diabetes independently. Conclusions To optimize glycemic control, CSII can be initiated and used effectively, both in children of all ages and in adolescents with type 1 diabetes. CSII may be ideal therapy for toddlers, with no apparent lower age boundary for initiating CSII; however, the parenting challenges and requirements for supportive education differ between toddlers and adolescents. When disease and pump management are appropriately individualized, CSII therapy can help children with diabetes achieve and sustain glycemic control. Lifestyle flexibility, quality-of-life improvement, and independence can thus begin early in childhood and be maintained throughout young adulthood.