Evaluation of Accuracy and Safety of the Next-Generation Up to 180-Day Long-Term Implantable Eversense Continuous Glucose Monitoring System: The PROMISE Study

Background: Use of continuous glucose monitoring (CGM) systems is being rapidly adopted as standard of care for insulin-requiring patients with diabetes. The PROMISE study (NCT03808376) evaluated the accuracy and safety of the next-generation implantable Eversense CGM system for up to 180 days. Methods: This was a prospective multicenter study involving 181 subjects with diabetes at 8 USA sites. All subjects were inserted with a primary sensor. Ninety-six subjects had a second sensor, either an identical sensor or a modified sensor (sacrificial boronic acid [SBA]), inserted in their other arm (53 and 43 subjects, respectively). Accuracy was evaluated by comparing CGM to YSI 2300 glucose analyzer (Yellow Springs Instrument [YSI]) values during 10 clinic visits (day 1-180). Confirmed event detection rates, calibration stability, sensor survival, and serious adverse events (SAEs) were evaluated. Results: For primary sensors, the percent CGM readings within 20%/20% of YSI values was 92.9%; overall mean absolute relative difference (MARD) was 9.1%. The confirmed alert detection rate at 70 mg/dL was 93% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 56%. Sixty-five percent of the primary sensors survived to 180 days. For the SBA sensors, the percent CGM readings within 20%/20% of YSI values was 93.9%; overall MARD was 8.5%. The confirmed alert detection rate at 70 mg/dL was 94% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 63%. Ninety percent of the SBA sensors survived to 180 days. No device- or insertion/removal procedure-related SAEs were reported. Conclusion: These data show the next-generation Eversense CGM system had sustained accuracy and safety up to 180 days, with an improved calibration scheme and survival, using the primary or SBA sensors.

Device profile of the eversense continuous glucose monitoring system for glycemic control in type-1 diabetes: overview of its safety and efficacy

INTRODUCTION

Continuous glucose monitoring (CGM) systems offer real-time data to facilitate diabetes management. The novel Eversense CGM has been approved in Europe and the US. The unique characteristics are the fully implantable sensor and the sensor life up to 180 days.

AREAS COVERED

This expert review describes the results of clinical trials, and the accuracy and safety of the Eversense system. The overall MARD ranges from 8.5% to 9.4%, the 20/20% agreement rate ranges from 84% to 94%, and the percent of values in zones A and B on the Clarke Error Grid is 99.2%. No device-related serious adverse events have been described during pivotal trial studies. The most frequently reported device- or procedure-related adverse events are sensor adhesive patch location site irritation (0.66%), inability to remove the sensor upon first attempt (0.76%), and location site infection (0.96%). Mean A1c reduction is about 0.4% from pivotal trials and real-world studies.

EXPERT OPINION

The Eversense system is novel and differentiated from transcutaneous CGM systems. The long life, the removable transmitter, and the on-body vibration alerts offer opportunities to properly manage diabetes with both MDI and insulin pump therapy.

Clinical use of a 180-day implantable glucose sensor improves glycated haemoglobin and time in range in patients with type 1 diabetes

AIMS

This real-world study evaluated the changes in glycated haemoglobin (HbA1c) and continuous glucose monitoring (CGM) metrics associated with use of the implantable 180-day Eversense CGM System (Eversense) in patients with type 1 diabetes.

MATERIALS AND METHODS

This was a prospective, multicentre, observational study among adult participants aged ≥18 years with type 1 diabetes across seven diabetes-care centres in Italy who had Eversense inserted for the first time. HbA1c was measured at baseline and at 180 days. Changes in time in range [TIR (glucose 70-180 mg/dL)], time above range [TAR (glucose >180 mg/dL)], time below range [TBR (glucose <70 mg/dL)] and glycaemic variability were also assessed. Data were also analysed by previous CGM use and by mode of insulin delivery.

RESULTS

One-hundred patients were enrolled (mean age 36 ± 12 years, mean baseline HbA1c 7.4 ± 0.92% [57 ± 10 mmol/mol]). Fifty-six per cent of patients were users of the continuous subcutaneous insulin infusion pump and 45% were previous users of CGM. HbA1c significantly decreased in patients after 180 days of sensor wear (-0.43% ± 0.69%, 5 ± 8 mmol/mol, P < 0.0001). As expected, CGM-naïve patients achieved the greatest reduction in HbA1c (-0.74% ± 0.48%, 8 ± 5 mmol/mol). TIR significantly increased and TAR and mean daily sensor glucose significantly decreased while TBR did not change after 180 days of sensor wear.

CONCLUSIONS

Real-world clinical use of the Eversense CGM System for 180 days was associated with significant improvements in HbA1c and CGM metrics among adults with type 1 diabetes. The study is registered on clinicaltrials.gov (NCT04160156).

Longitudinal Analysis of Real-World Performance of an Implantable Continuous Glucose Sensor over Multiple Sensor Insertion and Removal Cycles

The Eversense® Continuous Glucose Monitoring (CGM) System, with the first long-term, implantable glucose sensor, has been commercially available in Europe and South Africa since 2016 for adults with diabetes. The performance of the sensor over multiple, sequential 90- or 180-day cycles from either real-world experience or clinical studies has not been previously published. The Eversense Data Management System (DMS) was used to evaluate the accuracy of General Data Protection Regulation (GDPR)-compliant sensor glucose (SG) values against self-monitoring of blood glucose (SMBG) from June 2016 through August 2019 among patients with at least four sensor cycles from European and South African health care practices. Mean SG and associated measures of variability, glucose management indicator (GMI), and percent and time in various hypoglycemic, euglycemic, and hyperglycemic ranges were calculated for the 24-h time period over each cycle. In addition, transmitter wear time was evaluated across each sensor wear cycle. Among the 945 users included in the analysis, the mean absolute relative difference (standard deviation [SD]) using 152,206, 174,645, 206,024, and 172,587 calibration matched pairs against SMBG was 11.9% (3.6%), 11.5% (4.0%), 11.8% (4.7%), and 11.5% (4.1%) during the first four sensor cycles, respectively. Mean values of the CGM metrics over the first sensor cycle were 156.5 mg/dL for SG, 54.7 mg/dL for SD, 0.35 for coefficient of variation, and 7.04% for GMI. Percent SG at different glycemic ranges was as follows: <54 mg/dL was 1.1% (16 min), <70 mg/dL was 4.6% (66 min), ≥70-180 mg/dL (time in range) was 64.5% (929 min), >180-250 mg/dL was 22.8% (328 min), and >250 mg/dL was 8.1% (117 min). The median transmitter wear time over the first cycle was 83.2%. CGM metrics and wear time were similar over the subsequent three cycles. This real-world evaluation of adult patients with diabetes using the Eversense CGM System in the home setting demonstrated that the implantable sensor provides consistent stable accuracy and CGM metrics over multiple, sequential sensor cycles with no indication of degradation of sensor performance.

Real-World Safety of an Implantable Continuous Glucose Sensor Over Multiple Cycles of Use: A Post-Market Registry Study

Previously, the safety and accuracy of the Eversense continuous glucose monitoring (CGM) system were characterized in three pivotal trials among individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) with a single 90- or 180-day sensor insertion-removal cycle. The Post-Market Clinical Follow-up (PMCF) registry is a prospective study evaluating the long-term safety and performance of the Eversense CGM system over multiple sensor insertion-removal cycles among adults with T1D and T2D. All patients who had a sensor subcutaneously implanted across 534 participating centers in Europe and South Africa from June 2016 to August 2018 were enrolled. Adverse events (AEs) were recorded at each visit and patients were instructed to inform their clinic if they experienced any AEs between visits. AEs were adjudicated for relatedness to the device, procedure, or drug (dexamethasone acetate). The primary safety endpoint was the rate of related serious adverse events (SAEs) through four sensor insertion-removal cycles. The registry enrolled 3023 patients. As of last follow-up, 5417 sensors had been inserted with a total of 1260 patient-years (PYs) of follow-up: 969 patients had used the system for at least 6 months and 173 patients had used the system for at least 1 year. No related SAEs were reported. The most frequently reported related AEs were sensor location site infection (0.96%; 2.46 events per 100 PYs), inability to remove the sensor upon first attempt (0.76%; 1.90 events per 100 PYs), and adhesive patch location site irritation (0.66%; 1.59 events per 100 PYs). One nonserious allergic reaction to lidocaine was reported, which resolved with administration of an antihistamine. The full intended sensor life was achieved by 91% of 90-day sensors and 75% of 180-day sensors. The PMCF registry provides real-world evidence that the Eversense CGM system is safe over multiple cycles of use.

Real-World Data from the First U.S. Commercial Users of an Implantable Continuous Glucose Sensor

Background: The Eversense^® Continuous Glucose Monitoring (CGM) System, with the first 90-day implantable sensor, received FDA (Food and Drug Administration) approval in June 2018. No real-world experience has been published. Methods: Deidentified sensor glucose (SG) data from August 1, 2018 to May 11, 2019 in the Eversense Data Management System (DMS) were analyzed for the first 205 patients who reached a 90-day wear period on the Eversense CGM system. The mean SG, standard deviation (SD), median interquartile range, coefficient of variation (CV), glucose measurement index (GMI), and percent and time in minutes across glucose ranges were computed for the 24-h time period, the nighttime (00:00-06:00), and by 30-day wear periods. Sensor accuracy, sensor reinsertion rate, transmitter wear time, and safety data were assessed. Results: Of the 205 patients, 129 identified as type 1, 18 as type 2, and 58 were unreported. Fifty were CGM naive, 112 had prior CGM experience, and 43 were unreported. The mean SG was 161.8 mg/dL, SD was 57.4 mg/dL, CV was 0.35, and GMI was 7.18%. Percent SG at <54 mg/dL was 1.2% (18 min), <70 mg/dL was 4.1% (59.7 min), time in range (≥70-180 mg/dL) was 62.3% (897.7 min), >180-250 mg/dL was 21.9% (315.8 min), and >250 mg/dL was 11.6% (166.7 min). Nighttime values were similar. The glucometric values were similar over 30-day time periods of the sensor wear. The mean absolute relative difference (SD) using 27,708 calibration paired points against home blood glucose meters was 11.2% (11.3%). The sensor reinsertion rate was 78.5%. The median transmitter wear time was 83.6%. There were no related serious adverse events. Conclusion: The Eversense real-world data showed promising glycemic results, sensor accuracy, and safety. These data suggest that the Eversense CGM system is a valuable tool for diabetes management.

Efficacy and safety of suspend-before-low insulin pump technology in hypoglycaemia-prone adults with type 1 diabetes (SMILE): an open-label randomised controlled trial

BACKGROUND

Hypoglycaemia unawareness and severe hypoglycaemia can increase fear of hypoglycaemia and the risk of subsequent hypoglycaemic events. We aimed to assess the safety and efficacy of insulin pump therapy with integrated continuous glucose monitoring (CGM) and a suspend-before-low feature (Medtronic MiniMed 640G with SmartGuard) in hypoglycaemia-prone adults with type 1 diabetes.

METHODS

SMILE was an open-label randomised controlled trial done in people aged 24-75 years with type 1 diabetes for 10 years or longer, HbA_1c values of 5·8-10·0% (40-86 mmol/mol), and at high risk of hypoglycaemia (recent severe hypoglycaemia or hypoglycaemia unawareness defined by a Clarke or Gold score ≥4). Participants were enrolled from 16 centres (eg, clinics, hospitals, or university medical centres) in Canada, France, Italy, the Netherlands, and the UK. After baseline run-in phase (2 weeks), participants were randomly assigned to the MiniMed 640G pump (continuous subcutaneous insulin infusion) with self-monitoring of blood glucose (control group) or to the MiniMed 640G system with the suspend-before-low feature enabled (intervention group), for 6 months. The study statistician analysing the data was masked to group assignment until final database lock; because of the nature of the intervention, participants and treating clinicians could not be masked to group assignment. The primary outcome was the mean number of sensor hypoglycaemic events, defined as 55 mg/dL (3·1 mmol/L) or lower, and was analysed on an intention-to-treat basis in all randomly assigned participants. This trial is registered with ClinicalTrials.gov, number NCT02733991, and is completed.

FINDINGS

Between Dec 7, 2016, and March 27, 2018, 153 participants with a mean age 48·2 [12·4] years were randomly assigned: 77 to the control group (mean age 47·4 [12·5] years) and 76 to the intervention group (mean age 49·0 [12·2] years). After 6 months, the intervention group had significantly fewer hypoglycaemic events per participant per week (1·1 [SD 1·2] vs 4·1 [3·4] mean events, model-based treatment effect -2·9 [95% CI -3·5 to -2·3]; p<0·0001) and fewer severe hypoglycaemic events (instances requiring third-party assistance with carbohydrate or glucagon administration, or other resuscitative actions) overall (three vs 18; p=0·0036). The most common adverse events were hypoglycaemia (observed in ten [13%] of 77 participants in the control group vs four [5%] of 76 in the intervention group) and hyperglycaemia (observed in seven [9%] of 77 vs seven [9%] of 76). No serious adverse device effects or episodes of diabetic ketoacidosis were reported.

INTERPRETATION

Insulin pump therapy with integrated CGM and a suspend-before-low feature reduced the frequency of sensor hypoglycaemic and severe hypoglycaemic events in hypoglycaemia-prone adults compared with use of continuous subcutaneous insulin infusion without real-time CGM. These results suggest that this technology could be beneficial in this high-risk population.

FUNDING

Medtronic International Trading Sàrl and Medtronic Canada.

Safety Evaluation of the MiniMed 670G System in Children 7-13 Years of Age with Type 1 Diabetes

OBJECTIVE

To evaluate the safety of in-home use of the MiniMed™ 670G system with SmartGuard™ technology in children with type 1 diabetes (T1D).

METHODS

Participants (N = 105, ages 7-13 years, mean age 10.8 ± 1.8 years) were enrolled at nine centers (eight in the United States and one in Israel) and completed a 2-week baseline run-in phase in Manual Mode followed by a 3-month study phase with Auto Mode enabled. Sensor glucose (SG), glycated hemoglobin (HbA_1c), percentage of SG values across glucose ranges, and SG variability, during the run-in and study phases were compared. Participants underwent frequent sample testing with i-STAT^® venous reference measurement during a hotel period (6 days/5 nights) to evaluate the system's continuous glucose monitoring performance.

RESULTS

Auto Mode was used a median of 81% of the time. From baseline to end of study, overall SG dropped by 6.9 ± 17.2 mg/dL (P < 0.001), HbA_1c decreased from 7.9% ± 0.8% to 7.5% ± 0.6% (P < 0.001), percentage of time in target glucose range (70-180 mg/dL) increased from 56.2% ± 11.4% to 65.0% ± 7.7% (P < 0.001), and the SG coefficient of variation decreased from 39.6% ± 5.4% to 38.5% ± 3.8% (P = 0.009). The percentage of SG values within target glucose range was 68.2% ± 9.1% and that of i-STAT reference values was 65.6% ± 17.7%. The percentage of values within 20%/20 of the i-STAT reference was 85.2%. There were no episodes of severe hypoglycemia or diabetic ketoacidosis during the study phase.

CONCLUSION

In-home use of MiniMed 670G system Auto Mode for 3 months by children with T1D, similar to MiniMed 670G system use by adolescents and adults with T1D, was safe and associated with reduced HbA_1c levels and increased time in target glucose range, compared with baseline.

In-Clinic Evaluation of the MiniMed 670G System "Suspend Before Low" Feature in Children with Type 1 Diabetes

BACKGROUND

The Medtronic predictive low-glucose management (PLGM) algorithm automatically stops insulin delivery when sensor glucose (SG) is predicted to reach or fall below a preset low-glucose value within the next 30 min, and resumes delivery after hypoglycemia recovery. The present study evaluated the PLGM algorithm performance of the MiniMed™ 670G system SmartGuard™ "suspend before low" feature in children aged 7-13 years with type 1 diabetes (T1D).

METHOD

Participants (N = 105, mean ± standard deviation of 10.8 ± 1.8 years) underwent an overnight in-clinic evaluation of the "suspend before low" feature with a preset low limit of 65 mg/dL. After exercise, frequent sample testing (FST) was conducted every 5 min if values were <70 mg/dL; every 15 min if 70-80 mg/dL; and every 30 min if >80 mg/dL. First-day performance of the Guardian™ Sensor 3 glucose sensor and continuous glucose monitoring system was also evaluated.

RESULTS

Activation of the "suspend before low" feature occurred in 79 of the 105 participants, 79.7% (63/79) did not result in SG falling below 65 mg/dL. Mean glucose at activation was 102 ± 19 mg/dL and the initial insulin suspension duration was 87.5 ± 32.7 min. Four hours after insulin resumption, mean reference glucose was 130 ± 42 mg/dL. Mean absolute relative difference between the FST reference glucose and SG values on the first day of sensor wear was 11.4%. For the 26 participants in whom the "suspend before low" feature did not activate, none involved a reference glucose value ≤65 mg/dL, suggesting that the PLGM algorithm performed as intended.

CONCLUSION

In children aged 7-13 years with T1D, the "suspend before low" feature of the MiniMed 670G system demonstrated a hypoglycemia prevention rate of nearly 80% after exercise and did not involve rebound hyperglycemia. There were no events of severe hypoglycemia during the evaluation.

Impact of Reducing Glycated Hemoglobin on Healthcare Costs Among a Population with Uncontrolled Diabetes

INTRODUCTION

Glycated hemoglobin (A1C) is considered a "gold standard" measure of glycemic control in patients with diabetes and is correlated with a lower risk of diabetes complications and cost savings. This retrospective claims-analysis assessed the impact of A1C reduction on healthcare costs in patients with uncontrolled Type 1 and Type 2 diabetes.

METHODS

Using a large repository of US health plan administrative data linked to A1C values, patients with a diabetes diagnosis and at least two A1C values between 1 January 2009 and 31 December 2014 were selected to identify changes in A1C and associated changes in healthcare expenditure. We used all medical and pharmacy claims to calculate direct healthcare costs from 1 year prior to the index A1C to 2 years after the index A1C. A propensity score method was used to match patients with decreased A1C to patients whose A1C did not decrease, based on potentially confounding variables. Then, a generalized linear model regression was used to estimate the difference-in-difference (DD) effect on costs between the two groups.

RESULTS

Of the 3,197 patients who had a first A1C ≥ 9%, 2,273 patients (71%) had a decrease in A1C (Decreasers) and 924 patients (27%) had an increase in A1C (Non-decreasers). After matching, we compared 912 Decreasers to 912 Non-decreasers. Patients in the former group had average annual healthcare costs that were 24% lower during the first year of follow-up and 17% lower during the second year of follow-up, compared to patients whose A1C did not decrease. This reflected a savings of US$2503 and US$1690, respectively. For both time periods, the outpatient category was the largest contributor to cost savings.

DISCUSSION

In our analysis, A1C reduction among patients with T1DM and T2DM was associated with slower growth in healthcare costs within 1-2 years. These findings suggest that programs aimed at reducing A1C over a short timeframe may lead to substantial savings and may be worth pursuing by health plans and other payers.

Retrospective Analysis of 3-Month Real-World Glucose Data After the MiniMed 670G System Commercial Launch

Real-world data from the first 3141 patients who completed 3 months of SmartGuard™ Auto Mode-enabled MiniMed™ 670G system use during the MiniMed 670G System Commercial Launch are reported. CareLink™ system data uploaded by real-world patients in the Commercial Launch from March 17, 2017 to December 31, 2017 were deidentified and analyzed. Comparisons of overall and night (10:00 PM-07:00 AM) time spent below, within, and above target glucose range (TIR) (70-180 mg/dL) between the baseline Manual Mode and closed-loop Auto Mode periods were made. These were evaluated alongside data from the 124 patients (aged 14-75 years) who completed the 3-month MiniMed 670G system pivotal trial (NCT 2463097), from June 2, 2015 to March 7, 2016. Real-world patients used Auto Mode a median 80.8% of the time (19 h and 24 min of the day). The overall mean of time spent in TIR was 66.0% during baseline Manual Mode versus 73.3% during Auto Mode (P < 0.001); the mean percentage of sensor glucose values <70 mg/dL was 2.7% versus 2.1% (P < 0.001); and that >180 mg/dL was 31.4% versus 24.6% (P < 0.001). The nighttime and early morning (03:00 AM-06:00 AM) TIR during Auto Mode was greater than that during baseline Manual Mode (nighttime: 77.2% vs. 67.4% [P < 0.001], early morning: 70.9% vs. 84.6% [P < 0.001]). Similar differences between Manual Mode and Auto Mode TIR were observed across different age groups. A slight increase in total insulin delivered was also observed. Consistent with improved glycemic control demonstrated in the pivotal trial, analysis of CareLink system data from >3000 real-world patients who completed 3 months of Auto Mode-enabled MiniMed 670G system use demonstrated increased TIR and decreased time below and above TIR compared with baseline. These improved clinical outcomes were observed across a broad age range of patients with type 1 diabetes.

Accuracy of a Fourth-Generation Continuous Glucose Monitoring System in Children and Adolescents with Type 1 Diabetes

BACKGROUND

This study evaluated the safety and performance of the Guardian™ continuous glucose monitoring (CGM) system in children and adolescents with type 1 diabetes (T1D).

MATERIALS AND METHODS

Subjects 2-18 years of age (mean ± standard deviation [SD] 13.1 ± 3.9 years) with T1D and duration of diagnosis ≥1 year were enrolled at 11 sites in the United States and wore two Guardian Sensor 3 sensors in the abdomen and/or buttock. Sensors were connected to a transmitter paired with either a Guardian Connect system (i.e., mobile device with software application allowing display of sensor glucose [SG] values) or a Guardian Link 3 transmitter used as a Glucose Sensor Recorder (GSR). There were 145 participants who underwent a 6-h in-clinic frequent sample testing (FST) on day 1 (n = 54), day 3 (n = 48), or day 7 (n = 43) postsensor insertion. During FST, SG values were compared with a Yellow Springs Instrument (YSI) plasma reference every 5-15 min (n = 124, 7-18 years of age; n = 2, 2-6 years of age), or to a self-monitoring of blood glucose (SMBG) reference every 5-30 min (n = 19, 2-6 years of age).

RESULTS

The overall mean absolute relative difference (ARD ± SD) between SG and reference values (YSI or SMBG) when calibrating approximately every 12 h, was 10.9% ± 10.7% (3102 paired points) for sensors communicating with the Guardian Connect system and 11.1% ± 10.6% (2624 paired points) for sensors connected to the GSR. The overall percentage of SG values within ±20% of reference values >80 mg/dL or within 20 mg/dL of reference values ≤80 mg/dL was 87.8% for the Guardian Connect system and 86.7% for the GSR, respectively. There was one device-related adverse event of contact dermatitis, but no serious device-related adverse events.

CONCLUSIONS

The Guardian CGM system demonstrated good accuracy in children and adolescents. These findings support its use in sensor-integrated insulin pump platforms, as well as a standalone technology, for managing diabetes in pediatric populations.

Sensor-Augmented Pump-Based Customized Mathematical Model for Type 1 Diabetes

BACKGROUND

Simulations using mathematical models are important for studying, developing, and improving therapies for people with type 1 diabetes.

METHODS

The Medtronic CareLink^® database was used to create virtual patients with a variety of inter-insulin sensitivities, meal absorption rates, pharmacokinetics, age, and gender. In addition, intra-insulin sensitivities of the virtual patients change over a 24-h cycle.

RESULTS

A total of 2087 virtual patients were developed. The time percentage between 70 and 180 mg/dL of the CareLink uploads and the simulated virtual patients was 72.4% (18.6) and 74.1% (16.9), respectively. The time percentage <70 mg/dL of the real continuous glucose monitoring from CareLink uploads and the simulated virtual patients was 1% (2.4) and 1.7% (4.1), respectively. A simulation study with the virtual patients predicted the glycemic distribution after 2 h of insulin suspension as reported in the ASPIRE (Automation to Simulate Pancreatic Insulin Response) clinical trial. The 3 months outcomes of Medtronic's hybrid closed-loop 670G system pivotal trial were also predicted in a simulation study. The time percentage <70 mg/dL was 3.4% and 3.1%, and the time percentage between 71 and 180 mg/dL was 73.8% and 77.7% for 93 pivotal study adults (>18 years) and 90 adult (>28 years) virtual patients, respectively.

CONCLUSION

The Medtronic CareLink database was utilized to generate a large number of virtual patients with a variety of insulin sensitivities, pharmacokinetics, and meal absorption rates. This new simulation model can be potentially used to evaluate and prognosticate the outcomes of studies of artificial pancreas algorithms and systems.

Clinical and economic benefits of professional CGM among people with type 2 diabetes in the United States: analysis of claims and lab data

BACKGROUND

It is estimated that one in 10 people in the US have a diagnosis of diabetes. Type 2 diabetes accounts for 95% of all cases in the US, with annual costs estimated to be $246 billion per year. This study investigated the impact of a glucose-measuring intervention to the burden of type 2 diabetes.

OBJECTIVE

This analysis seeks to understand how professional continuous glucose monitoring (professional CGM) impacts clinical and economic outcomes when compared to patients who are not prescribed professional CGM.

METHODS

This study utilized a large healthcare claims and lab dataset from the US, and identified a cohort of patients who were prescribed professional CGM as identified by CPT codes 95250 and 95251. It calculated economic and clinical outcomes 1 year before and 1 year after the use of professional CGM, using a generalized linear model.

RESULTS

Patients who utilized professional CGM saw an improvement in hemoglobin A1C. The "difference-in-difference" calculation for A1C was shown to be -0.44%. There was no statistically significant difference in growth of total annual costs for people who used professional CGM compared to those who did not ($1,270, p = .08). Patients using professional CGM more than once per year had a -$3,376 difference in the growth of total costs (p = .05). Patients who used professional CGM while changing their diabetes treatment regimen also had a difference of -$3,327 in growth of total costs (p = .0023).

CONCLUSION

Significant clinical benefits were observed for patients who used professional CGM. Economic benefits were observed for patients who utilized professional CGM more than once within a 1-year period or who used it during a change of diabetes therapy. This suggests that professional CGM may help decrease rising trends in healthcare costs for people with type 2 diabetes, while also improving clinical outcomes.

The Effect of Prior Continuous Glucose Monitoring Use on Glycemic Outcomes in the Pivotal Trial of the MiniMed™ 670G Hybrid Closed-Loop System

A 3-month pivotal trial using the MiniMed™ 670G hybrid closed-loop (HCL) system in adolescent and adult patients with type 1 diabetes (T1D), relative to a 2-week baseline run-in period, resulted in increased sensor glucose (SG) values in target range (71-180 mg/dL), reduced HbA1c levels, and no events of diabetic ketoacidosis or severe hypoglycemia ( Clinicaltrials.gov : NCT02463097). This brief report evaluated how prior continuous glucose monitoring (CGM) experience influenced glycemic outcomes, in the same pivotal trial. HbA1c levels and the percentage of SG values in low, high, and in-target ranges were analyzed from participants (n = 124) completing the Hybrid Closed-Loop Pivotal Trial in T1D. There were 78 individuals comprising the prior CGM group and 46 comprising the no prior CGM group. Compared to baseline, HbA1c was reduced from 7.4% ± 0.9% to 6.9% ± 0.7% for the prior CGM group and from 7.5% ± 0.9% to 6.8% ± 0.5% for the no prior CGM group. For those with prior CGM experience, the mean percentage of in-target SG values increased from 66.9% ± 12.5% to 72.6% ± 9.1%, and for those with no prior CGM experience it increased from 66.6% ± 11.7% to 71.5% ± 8.5%. Similar improvement in glucose values in the low and high ranges, relative to baseline, was observed for both groups. Resulting outcomes, from baseline to study end, did not differ between each group. These findings suggest that individuals without prior CGM experience, and those already using CGM, will benefit similarly with use of the FDA-approved MiniMed 670G HCL system therapy.

Accuracy of a Fourth-Generation Subcutaneous Continuous Glucose Sensor

BACKGROUND

This study evaluated the accuracy and performance of a fourth-generation subcutaneous glucose sensor (Guardian^™ Sensor 3) in the abdomen and arm.

METHODS

Eighty-eight subjects (14-75 years of age, mean ± standard deviation [SD] of 42.0 ± 19.1 years) with type 1 or type 2 diabetes participated in the study. Subjects wore two sensors in the abdomen that were paired with either a MiniMed^™ 640G insulin pump, or an iPhone^® or iPod^® touch^® running a glucose monitoring mobile application (Guardian Connect system) and a third sensor in the arm, which was connected to a glucose sensor recorder (GSR). Subjects were also asked to undergo in-clinic visits of 12-14 h on study days 1, 3, and 7 for frequent blood glucose sample testing using a Yellow Springs Instrument (YSI) reference.

RESULTS

The overall mean absolute relative difference (MARD ± SD) between abdomen sensor glucose (SG) and YSI reference values was 9.6% ± 9.0% and 9.4% ± 9.8% for the MiniMed 640G insulin pump and Guardian Connect system, respectively; and 8.7% ± 8.0% between arm SG and YSI reference values. The percentage of SG values within 20% agreement of the YSI reference value (for YSI >80 mg/dL) was 90.7% with the MiniMed 640G insulin pump, 91.8% with the Guardian Connect system, and 93.1% for GSR-connected arm sensors. Mean functional sensor life, when calibrating 3-4 times/day, was 145.9 ± 39.3 h for sensors paired with the MiniMed 640G insulin pump, 146.1 ± 41.6 h for sensors paired with the Guardian Connect system, and 147.6 ± 40.4 h for sensors connected to the GSR. Responses to survey questions regarding sensor comfort and ease of use were favorable.

CONCLUSIONS

The Guardian Sensor 3 glucose sensor, whether located in abdomen or the arm, provided accurate glucose readings when compared with the YSI reference and demonstrated functional life commensurate with the intended 7-day use. ClinicalTrials.gov : NCT02246582.

Evaluation of a Predictive Low-Glucose Management System In-Clinic

BACKGROUND

Predictions based on continuous glucose monitoring (CGM) data are the basis for automatic suspension and resumption of insulin delivery by a predictive low-glucose management feature termed "suspend before low," which is part of the Medtronic MiniMed^® 640G combined insulin pump and CGM system. This study assessed the safety and performance characteristics of the system in an in-clinic setting at eight sites.

MATERIALS AND METHODS

In-clinic standardized increases in basal insulin delivery rates were used to induce nocturnal hypoglycemia in subjects (14-75 years) with type 1 diabetes wearing the MiniMed 640G system. The "suspend before low" feature was set at 65 mg/dL, and as a result, the predictive algorithm suspended insulin delivery when the forecasted glucose was predicted to be ≤85 mg/dL in 30 min (a 20 mg/dL safety buffer). Reference plasma glucose values (Yellow Springs Instruments [YSI], Yellow Springs, OH) were used to establish hypoglycemia and were defined as ≥2 consecutive values ≤65 mg/dL.

RESULTS

Eighty subjects were screened. Among the 69 successful completers, 27 experienced a hypoglycemic event and 42 did not, a prevention rate of 60%. The mean (±standard deviation) YSI value at the time of pump suspension was 101 ± 18.5 mg/dL, and the mean duration of the 68 "suspend before low" events was 105 ± 27 min. At 120 min after the start of the pump suspension events, the mean YSI value was 102 ± 34.6 mg/dL.

CONCLUSION

The MiniMed 640G "suspend before low" feature prevented 60% of induced predicted hypoglycemic events without significant rebound hyperglycemia.

An Expert Opinion on Advanced Insulin Pump Use in Youth with Type 1 Diabetes

Among children and adolescents with type 1 diabetes mellitus, the use of insulin pump therapy has increased since its introduction in the early 1980s. Optimal management of type 1 diabetes mellitus depends on sufficient understanding by patients, their families, and healthcare providers on how to use pump technology. The goal for the use of insulin pump therapy should be to advance proficiency over time from the basics taught at the initiation of pump therapy to utilizing advanced settings to obtain optimal glycemic control. However, this goal is often not met, and appropriate understanding of the full features of pump technology can be lacking. The objective of this review is to provide an expert perspective on the advanced features and use of insulin pump therapy, including practical guidelines for the successful use of insulin pump technology, and other considerations specific to patients and healthcare providers.

Glucose Outcomes with the In-Home Use of a Hybrid Closed-Loop Insulin Delivery System in Adolescents and Adults with Type 1 Diabetes

BACKGROUND

The safety and effectiveness of the in-home use of a hybrid closed-loop (HCL) system that automatically increases, decreases, and suspends insulin delivery in response to continuous glucose monitoring were investigated.

METHODS

Adolescents (n = 30, ages 14-21 years) and adults (n = 94, ages 22-75 years) with type 1 diabetes participated in a multicenter (nine sites in the United States, one site in Israel) pivotal trial. The Medtronic MiniMed^® 670G system was used during a 2-week run-in phase without HCL control, or Auto Mode, enabled (Manual Mode) and, thereafter, with Auto Mode enabled during a 3-month study phase. A supervised hotel stay (6 days/5 nights) that included a 24-h frequent blood sample testing with a reference measurement (i-STAT) occurred during the study phase.

RESULTS

Adolescents (mean ± standard deviation [SD] 16.5 ± 2.29 years of age and 7.7 ± 4.15 years of diabetes) used the system for a median 75.8% (interquartile range [IQR] 68.0%-88.4%) of the time (2977 patient-days). Adults (mean ± SD 44.6 ± 12.79 years of age and 26.4 ± 12.43 years of diabetes) used the system for a median 88.0% (IQR 77.6%-92.7%) of the time (9412 patient-days). From baseline run-in to the end of study phase, adolescent and adult HbA_1c levels decreased from 7.7% ± 0.8% to 7.1% ± 0.6% (P < 0.001) and from 7.3% ± 0.9% to 6.8% ± 0.6% (P < 0.001, Wilcoxon signed-rank test), respectively. The proportion of overall in-target (71-180 mg/dL) sensor glucose (SG) values increased from 60.4% ± 10.9% to 67.2% ± 8.2% (P < 0.001) in adolescents and from 68.8% ± 11.9% to 73.8% ± 8.4% (P < 0.001) in adults. During the hotel stay, the proportion of in-target i-STAT^® blood glucose values was 67.4% ± 27.7% compared to SG values of 72.0% ± 11.6% for adolescents and 74.2% ± 17.5% compared to 76.9% ± 8.3% for adults. There were no severe hypoglycemic or diabetic ketoacidosis events in either cohort.

CONCLUSIONS

HCL therapy was safe during in-home use by adolescents and adults and the study phase demonstrated increased time in target, and reductions in HbA_1c, hyperglycemia and hypoglycemia, compared to baseline.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02463097.

Effectiveness of Automated Insulin Management Features of the MiniMed® 640G Sensor-Augmented Insulin Pump

BACKGROUND

Automated insulin management features of the MiniMed® 640G sensor-augmented pump system include suspension in response to predicted low sensor glucose (SG) values ("suspend before low"), suspension in response to existing low SG values ("suspend on low"), and automatic restarting of basal insulin delivery upon SG recovery. The effectiveness of these features was evaluated using CareLink® software data.

METHODS

Anonymized data from MiniMed 640G system users (n = 4818), MiniMed 530G system users (n = 39,219), and MiniMed Paradigm® Veo™ system users (n = 43,193) who voluntarily uploaded pump and sensor data were retrospectively analyzed. Comparisons were made between days in which system features were enabled at any time and those in which they were not. Comparisons were also made between pump suspension events for which insulin delivery was automatically or manually resumed and between glycemic parameters of users who switched from the MiniMed Paradigm Veo system to the MiniMed 640G system.

RESULTS

Days in which the MiniMed 640G "suspend before low" feature was enabled had lower percentages of SG readings ≤70 mg/dL (3.9 mmol/L) or ≥240 mg/dL (13.3 mmol/L) than days when it was not enabled (P < 0.001 for each). Users who switched from the MiniMed Paradigm Veo system to the MiniMed 640G system had fewer excursions below ≤70 mg/dL (P < 0.001) and ≥240 mg/dL (P < 0.001). SG values following automatically resumed pump suspension events recovered more rapidly and had a more stabilized endpoint than following manually resumed events.

CONCLUSIONS

Automated insulin management features of the MiniMed 640G system can reduce the frequency of both high and low SG values and help stabilize SG after resumption of insulin delivery.

Predictors of Hypoglycemia in the ASPIRE In-Home Study and Effects of Automatic Suspension of Insulin Delivery

BACKGROUND

Hypoglycemia varies between patients with type 1 diabetes and is the main obstacle to therapy intensification. We investigated known and potential risk factors for hypoglycemia in subjects with type 1 diabetes.

METHOD

In the ASPIRE In-Home study (NCT01497938), a randomized trial of the threshold suspend (TS) feature of sensor-augmented insulin pump (SAP) therapy, subjects' propensity to nocturnal hypoglycemia (NH) was established in a 2-week run-in phase and assessed in a 3-month study phase via continuous glucose monitoring. Categorical variables were tested for association with NH rates in both phases.

RESULTS

Elevated rates of NH were significantly associated with baseline A1C ≤7%, with bolus insulin deliveries unassisted by the bolus estimation calculator, and with assignment to the control group during the study phase.

CONCLUSIONS

Routine use of the TS feature and the bolus estimation calculator are strategies that may reduce the risk of NH.

Retrospective analysis of the real-world use of the threshold suspend feature of sensor-augmented insulin pumps

BACKGROUND

The automatic Threshold Suspend (TS) feature of the MiniMed 530G system (Medtronic MiniMed, Inc., Northridge, CA), when enabled, suspends insulin delivery for up to 2 h when the sensor glucose (SG) value reaches a preset threshold.

MATERIALS AND METHODS

SG data from 20,973 patients who enabled the TS feature at their discretion and uploaded pump and sensor data to CareLink(®) (Medtronic MiniMed, Inc.) from October 15, 2013 to July 21, 2014 were analyzed. Comparisons between 758,382 patient-days wherein the TS feature was enabled at any time and 166,791 patient-days in which it was not enabled were made. Further comparisons were made between data collected during daytime (8:00 a.m. to 10:00 p.m.) and nighttime (10:00 p.m. to 8:00 a.m.) hours. Data from subsets of patients who enabled the TS feature all of the time (n=14,673) versus those who never enabled the TS feature (n=2,249) were also compared. Recovery from hypoglycemia during and after 2-h pump suspension events was also assessed.

RESULTS

The TS feature was enabled on 82% of patient-days. Patient-days in which the TS feature was enabled, compared with patient-days in which it was not, had 69% fewer SG values ≤50 mg/dL (0.64% vs. 2.09%, respectively; P<0.001). The reduction in hypoglycemia seen on TS-enabled days was more pronounced during nighttime than during daytime hours. SG data from full-time users of the TS feature reflected a 62% reduction in values ≤50 mg/dL and a 5.6% reduction in values ≥300 mg/dL compared with data from nonusers (P<0.001 for each). The median SG value at the start of 2-h suspensions was 60 (interquartile range [IQR], 57-66) mg/dL, immediately after was 87 (IQR, 63-123) mg/dL, and 4 h later was 164 (IQR, 117-220) mg/dL.

CONCLUSIONS

The TS feature, when enabled consistently, reduced hypoglycemic exposure, and for those who had it enabled 100% of the time, hyperglycemia was also reduced.

The PILGRIM study: in silico modeling of a predictive low glucose management system and feasibility in youth with type 1 diabetes during exercise

BACKGROUND

Predictive low glucose management (PLGM) may help prevent hypoglycemia by stopping insulin pump delivery based on predicted sensor glucose values.

MATERIALS AND METHODS

Hypoglycemic challenges were simulated using the Food and Drug Administration-accepted glucose simulator with 100 virtual patients. PLGM was then tested with a system composed of a Paradigm(®) insulin pump (Medtronic, Northridge, CA), an Enlite™ glucose sensor (Medtronic), and a BlackBerry(®) (Waterloo, ON, Canada)-based controller. Subjects (n=22) on continuous subcutaneous insulin infusion (five females, 17 males; median [range] age, 15 [range, 14-20] years; median [range] diabetes duration, 7 [2-14] years; median [range] glycated hemoglobin, 8.0% [6.7-10.4%]) exercised until the PLGM system suspended insulin delivery or until the reference blood glucose value (HemoCue(®); HemoCue GmbH, Großostheim, Germany) reached the predictive suspension threshold setting.

RESULTS

PLGM reduced hypoglycemia (<70 mg/dL) in silico by 26.7% compared with no insulin suspension, as opposed to a 5.3% reduction in hypoglycemia with use of low glucose suspend (LGS). The median duration of hypoglycemia (time spent <70 mg/dL) with PLGM was significantly less than with LGS (58 min vs. 101 min, respectively; P<0.001). In the clinical trial the hypoglycemic threshold during exercise was reached in 73% of the patients, and hypoglycemia was prevented in 80% of the successful experiments. The mean (±SD) sensor glucose at predictive suspension was 92±7 mg/dL, resulting in a postsuspension nadir (by HemoCue) of 77±22 mg/dL. The suspension lasted for 90±35 (range, 30-120) min, resulting in a sensor glucose level at insulin resumption of 97±19 mg/dL.

CONCLUSIONS

In silico modeling and early feasibility data demonstrate that PLGM may further reduce the severity of hypoglycemia beyond that already established for algorithms that use a threshold-based suspension.

The effects of lowering nighttime and breakfast glucose levels with sensor-augmented pump therapy on hemoglobin A1c levels in type 1 diabetes

OBJECTIVE

This study determined the association of continuous glucose monitoring glucose (CGM-glucose) levels at different times of the day with improvement in glycated hemoglobin (HbA1c) levels. The potential application of these data is to focus effort to improve glucose control in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Data were analyzed from 196 patients with type 1 diabetes who were randomized to receive sensor-augmented pump therapy in the 1-year STAR 3 trial. CGM-glucose values and HbA1c levels from baseline and after 1 year were evaluated to determine associations of improvement in CGM-glucose at different times of the day with longitudinal improvement in HbA1c.

RESULTS

Improvement in HbA1c levels after 1 year was related to improvement in mean CGM-glucose levels in daytime (6 a.m.-midnight), overnight (midnight-6 a.m.), and each mealtime period (P<0.0001 for each). In multivariable analysis, only improvement in breakfast meal period was associated with improvement in HbA1c after 1 year, explaining 59% of the HbA1c improvement using the partial R(2) test. Moreover, among those patients who only improved CGM-glucose in the overnight period there was an associated improvement in breakfast meal period CGM-glucose of 26 ± 22 mg/dL (P<0.01).

CONCLUSIONS

Breakfast period glucose improvement had the greatest effect on lowering HbA1c levels in patients with type 1 diabetes. Improving glucose control overnight resulted in subsequent improvement in the breakfast period. Although glucose control should be improved at all times, methods to improve overnight and post-breakfast glucose levels may be of primary importance in improving glucose control in patients with type 1 diabetes.

Hypoglycemia begets hypoglycemia: the order effect in the ASPIRE in-clinic study

BACKGROUND

The ASPIRE in-clinic study established that automatic suspension of insulin with the threshold suspend (TS) feature reduces the duration of induced hypoglycemia. The study's crossover design allowed the effects of antecedent hypoglycemia to be studied.

SUBJECTS AND METHODS

The study enrolled 50 subjects who exercised until plasma glucose (YSI glucose and lactate analyzer; YSI, Inc., Yellow Springs, OH) reached ≤85 mg/dL. Hypoglycemia was evaluated after the YSI value reached <70 mg/dL. In TS experiments, insulin was stopped for 2 h once a sensor glucose (SG) value of ≤70 mg/dL was detected; in control experiments, basal insulin delivery continued. Subjects were randomly assigned to Group A (TS in Period 1; control in Period 2) or Group B (control in Period 1; TS in Period 2). Experiments were separated by 3-10 days.

RESULTS

Hypoglycemia was 63.7 min shorter in Period 1 TS experiments (no preceding control experiment) than in Period 2 TS experiments (one or more preceding control experiment(s)) (P<0.01). The number of experiments prior to a successful TS experiment was lower for Period 1 than for Period 2 (0.36 ± 0.64 vs. 1.57 ± 0.84; P<0.001), as was the cumulative duration of antecedent hypoglycemia (16.6 min vs. 204.6 min; P<0.001). The between-groups difference in hypoglycemia duration was not attributable to differences in SG rates of change, the duration of exercise, or area under the curve of <70 mg/dL × min in the 2 days before the successful experiment (all P>0.3).

CONCLUSIONS

The TS feature's ability to mitigate hypoglycemia was decreased by an episode or episodes of prolonged antecedent hypoglycemia, suggesting hypoglycemia begets hypoglycemia. The effect of antecedent hypoglycemia should be taken into consideration in the design of future experiments assessing strategies to reduce hypoglycemia.

Threshold-based insulin-pump interruption for reduction of hypoglycemia

BACKGROUND

The threshold-suspend feature of sensor-augmented insulin pumps is designed to minimize the risk of hypoglycemia by interrupting insulin delivery at a preset sensor glucose value. We evaluated sensor-augmented insulin-pump therapy with and without the threshold-suspend feature in patients with nocturnal hypoglycemia.

METHODS

We randomly assigned patients with type 1 diabetes and documented nocturnal hypoglycemia to receive sensor-augmented insulin-pump therapy with or without the threshold-suspend feature for 3 months. The primary safety outcome was the change in the glycated hemoglobin level. The primary efficacy outcome was the area under the curve (AUC) for nocturnal hypoglycemic events. Two-hour threshold-suspend events were analyzed with respect to subsequent sensor glucose values.

RESULTS

A total of 247 patients were randomly assigned to receive sensor-augmented insulin-pump therapy with the threshold-suspend feature (threshold-suspend group, 121 patients) or standard sensor-augmented insulin-pump therapy (control group, 126 patients). The changes in glycated hemoglobin values were similar in the two groups. The mean AUC for nocturnal hypoglycemic events was 37.5% lower in the threshold-suspend group than in the control group (980 ± 1200 mg per deciliter [54.4 ± 66.6 mmol per liter] × minutes vs. 1568 ± 1995 mg per deciliter [87.0 ± 110.7 mmol per liter] × minutes, P<0.001). Nocturnal hypoglycemic events occurred 31.8% less frequently in the threshold-suspend group than in the control group (1.5 ± 1.0 vs. 2.2 ± 1.3 per patient-week, P<0.001). The percentages of nocturnal sensor glucose values of less than 50 mg per deciliter (2.8 mmol per liter), 50 to less than 60 mg per deciliter (3.3 mmol per liter), and 60 to less than 70 mg per deciliter (3.9 mmol per liter) were significantly reduced in the threshold-suspend group (P<0.001 for each range). After 1438 instances at night in which the pump was stopped for 2 hours, the mean sensor glucose value was 92.6 ± 40.7 mg per deciliter (5.1 ± 2.3 mmol per liter). Four patients (all in the control group) had a severe hypoglycemic event; no patients had diabetic ketoacidosis.

CONCLUSIONS

This study showed that over a 3-month period the use of sensor-augmented insulin-pump therapy with the threshold-suspend feature reduced nocturnal hypoglycemia, without increasing glycated hemoglobin values. (Funded by Medtronic MiniMed; ASPIRE ClinicalTrials.gov number, NCT01497938.).

Model-based sensor-augmented pump therapy

BACKGROUND

In insulin pump therapy, optimization of bolus and basal insulin dose settings is a challenge. We introduce a new algorithm that provides individualized basal rates and new carbohydrate ratio and correction factor recommendations. The algorithm utilizes a mathematical model of blood glucose (BG) as a function of carbohydrate intake and delivered insulin, which includes individualized parameters derived from sensor BG and insulin delivery data downloaded from a patient's pump.

METHODS

A mathematical model of BG as a function of carbohydrate intake and delivered insulin was developed. The model includes fixed parameters and several individualized parameters derived from the subject's BG measurements and pump data. Performance of the new algorithm was assessed using n = 4 diabetic canine experiments over a 32 h duration. In addition, 10 in silico adults from the University of Virginia/Padova type 1 diabetes mellitus metabolic simulator were tested.

RESULTS

The percentage of time in glucose range 80-180 mg/dl was 86%, 85%, 61%, and 30% using model-based therapy and [78%, 100%] (brackets denote multiple experiments conducted under the same therapy and animal model), [75%, 67%], 47%, and 86% for the control experiments for dogs 1 to 4, respectively. The BG measurements obtained in the simulation using our individualized algorithm were in 61-231 mg/dl min-max envelope, whereas use of the simulator's default treatment resulted in BG measurements 90-210 mg/dl min-max envelope.

CONCLUSIONS

The study results demonstrate the potential of this method, which could serve as a platform for improving, facilitating, and standardizing insulin pump therapy based on a single download of data.

Diabetes screening with hemoglobin A(1c) versus fasting plasma glucose in a multiethnic middle-school cohort

OBJECTIVE

To characterize middle-school students from the HEALTHY study with glycemic abnormalities, specifically high-risk hemoglobin A(1c) (A1C) (hrA1C; A1C = 5.7-6.4%) and impaired fasting glucose (IFG; fasting plasma glucose [FPG] = 100-125 mg/dL).

RESEARCH DESIGN AND METHODS

History was collected by self-report, physical measurement was collected by trained study staff, and fasting blood was drawn by trained phlebotomists and analyzed centrally.

RESULTS

At baseline, among 3,980 sixth graders, 128 (3.2%) had hrA1C and 635 (16.0%) had IFG. Compared with A1C <5.7%, hrA1C was associated with non-Hispanic black race/ethnicity, family history of diabetes, and higher measurements of BMI, waist circumference, and fasting insulin. Compared with FPG <100 mg/dL, IFG was associated with Hispanic ethnicity; increased BMI, waist circumference, and fasting insulin; higher frequency of high blood pressure; and higher mean triglycerides. Two years later, children with hrA1C persisted as hrA1C in 59.4%, and one child (0.8%) developed A1C ≥6.5%; children with IFG persisted with IFG in 46.9%, and seven children (1.1%) developed FPG ≥126 mg/dL. Those with hrA1C compared with IFG had a higher BMI in sixth grade, which persisted to eighth grade.

CONCLUSIONS

In the HEALTHY study cohort, hrA1C and IFG define different groups of youth with differentially increased diabetes risk markers. IFG is approximately fivefold more common, but hrA1C is more persistent over time. Optimal screening strategies for diabetes in youth remain unresolved.

Reduction in duration of hypoglycemia by automatic suspension of insulin delivery: the in-clinic ASPIRE study

BACKGROUND

The efficacy of automatic suspension of insulin delivery in induced hypoglycemia among subjects with type 1 diabetes was evaluated.

SUBJECTS AND METHODS

In this randomized crossover study, subjects used a sensor-augmented insulin pump system with a low glucose suspend (LGS) feature that automatically stops insulin delivery for 2 h following a sensor glucose (SG) value ≤70 mg/dL. Subjects fasted overnight and exercised until their plasma glucose (measured with the YSI 2300 STAT Plus™ glucose and lactate analyzer [YSI Life Sciences, Yellow Springs, OH]) value reached ≤85 mg/dL on different occasions separated by washout periods lasting 3-10 days. Exercise sessions were done with the LGS feature turned on (LGS-On) or with continued insulin delivery regardless of SG value (LGS-Off). The order of LGS-On and LGS-Off sessions was randomly assigned. YSI glucose data were used to compare the duration and severity of hypoglycemia from successful LGS-On and LGS-Off sessions and to estimate the risk of rebound hyperglycemia after pump suspension.

RESULTS

Fifty subjects attempted 134 sessions, 98 of which were successful. The mean±SD hypoglycemia duration was less during LGS-On than during LGS-Off sessions (138.5±76.68 vs. 170.7±75.91 min, P=0.006). During LGS-On compared with LGS-Off sessions, mean nadir YSI glucose was higher (59.5±5.72 vs. 57.6±5.69 mg/dL, P=0.015), as was mean end-observation YSI glucose (91.4±41.84 vs. 66.2±13.48 mg/dL, P<0.001). Most (53.2%) end-observation YSI glucose values in LGS-On sessions were in the 70-180 mg/dL range, and none was >250 mg/dL.

CONCLUSIONS

Automatic suspension of insulin delivery significantly reduced the duration and severity of induced hypoglycemia without causing rebound hyperglycemia.

Usage and effectiveness of the low glucose suspend feature of the Medtronic Paradigm Veo insulin pump

BACKGROUND

Sensor-augmented insulin pumps may be programmed to suspend insulin delivery in response to hypoglycemia. The Medtronic Paradigm® Veo™ pump with automatic low glucose suspend (LGS) was released in 2009. Data from 7 months of real-world use of the system were analyzed to assess usage patterns and effectiveness of LGS.

METHOD

Data from 935 patients totaling 49,867 patient days were collected; the LGS feature was on for 82% of these days. A subset of 278 subjects who used the pump for ≥3 months was analyzed separately; these subjects provided 28,401 patient days of data, with LGS used for 92% of the time.

RESULTS

The LGS threshold was most commonly set between 50 and 60 mg/dl. A total of 27,216 LGS events occurred, and 60% began in the afternoon or evening. The median duration of LGS events was 9.87 min, 45% lasted for <5 min, and 11% lasted for >115 min (equivalent to the full extent of the LGS event between 115 and 120 min). Among the episodes lasting for >115 min, the mean sensor glucose (SG) was 58.8 ± 12.4 mg/dl at LGS activation (time 0), rose to 102.2 ± 52.8 mg/dl by the end of the LGS episode (when insulin delivery was automatically resumed), and was 150.1 ± 68.6 mg/dl at 240 min. In the 278-subject subgroup, LGS usage significantly reduced the number of SG readings <50 mg/dl (p = 0.001) and >300 mg/dl (p = 0.001).

CONCLUSIONS

The LGS feature was on for most of the patient days in the study. Most LGS episodes lasted for <10 min. Use of the LGS feature significantly reduced exposure to hypoglycemia. Profound hyperglycemia resulting from LGS episodes lasting >115 min was not observed.

A longitudinal assessment of lipids in youth with type 1 diabetes

BACKGROUND

Type 1 diabetes and dyslipidemia are known risk factors for cardiovascular disease (CVD), but the relationship between lipid levels in youth with type 1 diabetes and future CVD remains unknown.

OBJECTIVE

To characterize lipid levels and CVD risk factors over time in youth with type 1 diabetes.

SUBJECTS

The study included adolescents with type 1 diabetes (12-25 yr) with a minimum of 3-yr follow-up.

METHODS

A longitudinal prospective, observational study of 46 youth with type 1 diabetes was performed. Fasting lipid profiles, A1C, and body mass index (BMI) were measured every 6 months for at least 3 yr (median 4.2 yr). Low-density lipoprotein (LDL)-cholesterol, total cholesterol (TC), and triglycerides (TG) were divided into categorical variables.

RESULTS

At baseline, median age was 14.3 yr, mean diabetes duration was 6.4 ± 3.8 yr, mean A1C was 8.1 ± 1.0%, and median BMI z-score was 0.92. Fifty percent of subjects had LDL levels ≤ 100 mg/dL (≤ 2.6 mmol/L) at study onset. After adjusting for confounding factors, increasing BMI z-score [β = 0.2, 95% confidence interval (CI ) = 0.03-0.38, p = 0.03] and increasing A1C (β = 0.18, 95% CI = 0.08-0.29, p = 0.001) were associated with increasing LDL category over time. Non-Hispanic ethnicity (β = 0.45, 95% CI = 0.12-0.79, p = 0.008) and family history of stroke (β = 0.38, 95% CI = 0.04-0.72, p = 0.03) were also associated with increasing LDL category. Age, diabetes duration, and tobacco exposure were not related to change in LDL. Increasing A1C was associated with increases in TG (β = 18.1, 95% CI = 2.3-33.9, p = 0.03), TC (β = 20.3, 95% CI = 9.0-31.5, p < 0.0001), and LDL (β = 13.4, 95% CI = 3.17- 23.6, p = 0.01).

CONCLUSION

Glycemic control and BMI are modifiable risk factors for dyslipidemia in youth with type 1 diabetes.

Characteristics of adolescents and youth with recent-onset type 2 diabetes: the TODAY cohort at baseline

CONTEXT

The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) cohort represents the largest and best-characterized national sample of American youth with recent-onset type 2 diabetes.

OBJECTIVE

The objective of the study was to describe the baseline characteristics of participants in the TODAY randomized clinical trial.

DESIGN

Participants were recruited over 4 yr at 15 clinical centers in the United States (n = 704) and enrolled, randomized, treated, and followed up 2-6 yr.

SETTING

The study was conducted at pediatric diabetes care clinics and practices.

PARTICIPANTS

Eligible participants were aged 10-17 yr inclusive, diagnosed with type 2 diabetes for less than 2 yr and had a body mass index at the 85th percentile or greater.

INTERVENTIONS

After baseline data collection, participants were randomized to one of the following groups: 1) metformin alone, 2) metformin plus rosiglitazone, or 3) metformin plus a lifestyle program of weight management.

MAIN OUTCOME MEASURES

Baseline data presented include demographics, clinical/medical history, biochemical measurements, and clinical and biochemical abnormalities.

RESULTS

At baseline the cohort included the following: 64.9% were female; mean age was 14.0 yr; mean diabetes duration was 7.8 months; mean body mass index Z-score was 2.15; 89.4% had a family history of diabetes; 41.1% were Hispanic, 31.5% were non-Hispanic black; 38.8% were living with both biological parents; 41.5% had a household annual income of less than $25,000; 26.3% had a highest education level of parent/guardian less than a high school degree; 26.3% had a blood pressure at the 90th percentile or greater; 13.6% had a blood pressure at the 95th percentile or greater; 13.0% had microalbuminuria; 79.8% had a low high-density lipoprotein level; and 10.2% had high triglycerides.

CONCLUSIONS

The TODAY cohort is predominantly from racial/ethnic minority groups, with low socioeconomic status and a family history of diabetes. Clinical and biochemical abnormalities and comorbidities are prevalent within 2 yr of diagnosis. These findings contribute greatly to our understanding of American youth with type 2 diabetes.

Severe obesity and selected risk factors in a sixth grade multiracial cohort: the HEALTHY study

The purpose of this study was to document the prevalence of severe obesity and associated risk in the HEALTHY cohort. A total of 6,365 students were assessed at school-based screenings. Results showed that 6.9% of students were severely obese. Severe obesity was associated with elevated cardiometabolic risk and race/ethnicity. Severe obesity is common and requires preventive intervention.

Insights from a large observational database of continuous glucose monitoring adoption, insulin pump usage and glycemic control: the CareLink™ database

OBJECTIVE

The CareLink™ (Medtronic, Inc., Northridge, CA) database houses data from continuous glucose monitoring (CGM), insulin pumps, and blood glucose (BG) meters. This study examined CGM usage and its relationship to insulin delivery and glycemia in CareLink users with type 1 diabetes mellitus (T1DM).

METHODS

Users whose CareLink accounts contained =120 days of pump and glucose readings within a 180-day interval were further selected and stratified based on the frequency of CGM use and adequacy of glycemic control; correlations between these variables were sought.

RESULTS

The proportion of subjects with pre-specified favorable glycemic parameters rose with increasing sensor use (p<0.001). These subjects administered more and smaller boluses, gave a higher proportion of their total daily dose (TDD) of insulin as boluses, and maintained lower TDDs than those with pre-specified less-favorable glycemic parameters (all p<0.001).

CONCLUSIONS

A favorable dose effect of CGM use was evident. CGM data facilitates smaller and more frequent bolus dosing, allowing for improved glycemic control.

Risk factors for type 2 diabetes in a sixth- grade multiracial cohort: the HEALTHY study

OBJECTIVE

HEALTHY is a 3-year middle school intervention program designed to reduce risk factors for type 2 diabetes. The prevalence of diabetes risk factors at baseline in a cohort of 6,358 sixth-grade students is reported.

RESEARCH DESIGN AND METHODS

Forty-two schools at seven U.S. sites were randomly assigned to intervention or control. Students participated in baseline data collection during fall of 2006.

RESULTS

Overall, 49.3% of children had BMI >or=85th percentile, 16.0% had fasting blood glucose >or=100 mg/dl (<1% had fasting blood glucose >or=126 mg/dl), and 6.8% had fasting insulin >or=30 microU/ml. Hispanic youth were more likely to have BMI, glucose, and insulin levels above these thresholds than blacks and whites.

CONCLUSIONS

Sixth-grade students in schools with large minority populations have high levels of risk factors for type 2 diabetes. The HEALTHY intervention was designed to modify these risk factors to reduce diabetes incidence.