Efficacy of an Overnight Predictive Low-Glucose Suspend System in Relation to Hypoglycemia Risk Factors in Youth and Adults With Type 1 Diabetes

Abstract

An important goal of a closed loop system for individuals with type 1 diabetes is prevention of hypoglycemia, particularly overnight. We developed a system to suspend insulin pump delivery overnight when the glucose trend predicts hypoglycemia.1,2 The predictive low-glucose suspend (PLGS) system involves a continuous glucose monitor (CGM) device communicating with an insulin pump via a laptop computer that contains the hypoglycemia prediction algorithm. In an at-home randomized trial of 81 children aged 4-14 1 and 45 adults aged 15-45 2 with type 1 diabetes, we found that the PLGS system reduced the frequency of nocturnal hypoglycemia by 25% and 36%, respectively, compared with a control arm. Median time less than 70 mg/dL was reduced by more than 50%, prolonged nocturnal hypoglycemia (≤60 mg/dl for >2 hours) was reduced more than 3-fold, and there was no meaningful increase in hyperglycemia or ketosis. While the PLGS system greatly reduced hypoglycemia overall, We developed a system to suspend insulin pump delivery overnight when the glucose trend predicts hypoglycemia. This predictive low-glucose suspend (PLGS) system substantially reduces nocturnal hypoglycemia without an increase in morning ketosis. Evaluation of hypoglycemia risk factors that could potentially influence the efficacy of the system remains critical for understanding possible problems with the system and identifying patients that may have the greatest benefit when using the system. Methods:The at-home randomized trial consisted of 127 study participants with hemoglobin A1c (A1C) of ≤8.5% (mmol/ mol) for patients aged 4-14 years and ≤8.0% for patient aged 15-45 years. Factors assessed included age, gender, A1C, diabetes duration, daily percentage basal insulin, total daily dose of insulin (units/kg-day), bedtime BG, bedtime snack, insulin on board, continuous glucose monitor (CGM) rate of change (ROC), day of the week, time system activated, daytime exercise intensity, and daytime CGM-measured hypoglycemia. Results:The PLGS system was effective in preventing hypoglycemia for each factor subgroup. There was no evidence that the PLGS system was more or less effective in preventing hypoglycemia in any one subgroup compared with the other subgroups based on that factor. In addition, the effect of the system on overnight hyperglycemia did not differ in subgroups.Conclusions: The PLGS system tested in this study effectively reduced hypoglycemia without a meaningful increase in hyperglycemia across a variety of factors.

Discrepancies Between Blood Glucose and Interstitial Glucose—Technological Artifacts or Physiology: Implications for Selection of the Appropriate Therapeutic Target

“…[15][16][17][18][19] By contrast, CGM detects not only all hypoglycemic events but also makes it possible to evaluate the intensity of each hypoglycemic event. The strength and duration of a given hypoglycemic event (which might be clinically more important than the sheer number of such events) can be calculated as the area under the curve (AUC) for values below a defined hypoglycemic level (eg, 55 or 70 mg/dl) and the time spent below that threshold.…”

An Adaptive Nonlinear Basal-Bolus Calculator for Patients With Type 1 Diabetes

“…[36][37][38][39] The control algorithm in the AP can be used in complement with the basal-bolus calculator to stabilize the blood glucose during the night and to suspend the administration of insulin in case of predicted hypoglycemia. 40 Moreover, the basalbolus calculator can be used to estimate individualized patient information (total daily insulin, insulin sensitivity factor, insulin action time), such that adaptive tuning of AP control algorithms is possible. 36,41,42 These simulations did not cover hyperglycemic events outside mealtimes or a prolonged postprandial hyperglycemia.…”

De la bomba de insulina y el monitoreo continuo de glucosa al páncreas artificial

“…Los umbrales de glicemia para dicha suspensión son programados individualmente para cada paciente. La auto-suspensión por parte de estos equipos ha demostrado ser segura [12][13][14] .…”

“…El uso de MCG-TR en el contexto de SAPT con suspensión automática de la infusión de insulina reduce de forma significativa la tasa, duración y severidad de los episodios de hipoglicemia, sin deterioro del control glicémico [12][13][14][27][28][29] .…”