NCT01835964

Biobehavioral Mechanisms of Glucose Variability

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 30 (actual)
• Sponsor: University of Virginia · Academic / Other
• Sex: All
• Age: 21 Years – 65 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study is to investigate how blood sugar changes in response to insulin and what the body does to counter-act low blood sugar in people with Type 1 Diabetes Mellitus. Insulin sensitivity is the term used to describe blood sugar changes within the body in response to insulin. Greater understanding of insulin sensitivity, particularly how the body responds to low blood sugar, will help us to better predict how blood sugar levels will change. All subjects will receive a liquid mixed-meal and will have their blood sugar response monitored in order to study insulin sensitivity. All subjects will receive additional insulin injections that are given to cause a low blood sugar in order to understand how the body responds to a low blood sugar. All subjects will be closely monitored during the time the insulin is given, by frequent checks of blood sugar and constant medical and nursing supervision. Details of the visits, tests and procedures are described below. During this study, the study team will ask that subjects to use their own insulin pump and own glucometer. Subjects will need to use the same glucometer for the entire study. Subjects will be provided 1 box of strips. Subjects will be required to use lispro (Humalog) insulin 2-3 days before your inpatient admission which will be provided free of charge.

Detailed description

Glucose variability (GV) in type 1 diabetes (T1DM) is increasingly viewed as a primary marker of glycemic control, responsible, along with chronic hyperglycemia reflected by HbA1c, for diabetes complications. In this study, we propose to investigate: (i) the time course of deterioration of physiological glucoregulatory mechanisms leading to increased GV, and (ii) the association of GV with metabolic and behavioral factors such as insulin sensitivity and treatment adequacy. Our primary hypothesis is: Glucose variability in T1DM is triggered by behavioral events (e.g. meals, insulin injection, exercise) that challenge the metabolic system. The timing and the magnitude of the behavioral challenges, and the ability of the metabolic mechanisms to absorb these challenges, determine the magnitude of GV. This process develops in a certain time frame, and can be accelerated by inadequate treatment, or attenuated by precise timing and dosing of bio-behavioral control. This study will use a combination of treatment records, continuous glucose monitoring (CGM), and an inpatient admission to clarify the relationships between behavioral challenges to the metabolic system, physiological glucoregulatory mechanisms, and GV. This study will test the following hypotheses: 1. Suboptimal treatment behavior, e.g. insulin mistiming (early/late meal insulin) or unbalanced insulin (higher basal/bolus ratio), is correlated with higher GV and repeated hypo- and hyperglycemia; this relationship is mediated by a patients' insulin sensitivity; 2. A metabolic challenge (e.g. consecutive sequence of hypo- and hyperglycemia), will push the metabolic system into a transient super-critical state characterized by increased GV as defined by the Variability Grid Analysis (VGA) and the Average Daily Risk Range (ADRR), which will persist for several days beyond the discontinuation of the challenge.

Conditions

• Diabetes Mellitus, Type 1

Interventions

Type	Name	Description
PROCEDURE	Glucose Variability Observation	On the morning of \~Day 17 for a metabolic challenge involving a standardized liquid mixed meal intended to raise the blood glucose approximately 150 mg/dl, followed four hours later by the induction of hypoglycemia with intravenous insulin administration with goal glucose of 55 mg/dl. After carbohydrate rescue, the subject will receive a meal and will be monitored until glucose is stable above 80 mg/dl.

Timeline

• Start date: 2013-04-01
• Primary completion: 2014-01-01
• Completion: 2014-02-01
• First posted: 2013-04-19
• Last updated: 2023-07-07
• Results posted: 2023-07-07

Locations

1 site across 1 country: United States