Preventing hypoglycemia using predictive alarm algorithms and insulin pump suspension.

BACKGROUND: Nocturnal hypoglycemia is a significant problem. From 50% to 75% of hypoglycemia seizures occur at night. Despite the development of real-time glucose sensors (real-time continuous glucose monitor [CGM]) with hypoglycemic alarms, many patients sleep through these alarms. The goal of this pilot study was to assess the feasibility using a real-time CGM to discontinue insulin pump therapy when hypoglycemia was predicted. METHODS: Twenty-two subjects with type 1 diabetes had two daytime admissions to a clinical research center. On the first admission their basal insulin was increased until their blood glucose level was <60 mg/dL. On the second admission hypoglycemic prediction algorithms were tested to determine if hypoglycemia was prevented by a 90-min pump shutoff and to determine if the pump shutoff resulted in rebound hyperglycemia. RESULTS: Using a statistical prediction algorithm with an 80 mg/dL threshold and a 30-min projection horizon, hypoglycemia was prevented 60% of the time. Using a linear prediction algorithm with an 80 mg/dL threshold and a 45-min prediction horizon, hypoglycemia was prevented 80% of the time. There was no rebound hyperglycemia following pump suspension. CONCLUSIONS: Further development of algorithms is needed to prevent all episodes of hypoglycemia from occurring.

Timing of meal insulin boluses to achieve optimal postprandial glycemic control in patients with type 1 diabetes.

OBJECTIVE: This study determined the optimal timing of insulin bolus administration in relation to meal consumption in adolescents and adults with type 1 diabetes. STUDY DESIGN AND METHODS: Twenty-three subjects participated in this crossover study consisting of three treatment arms: delivering an insulin glulisine bolus by insulin pump 20 min prior to a meal ("PRE"), immediately before the meal ("START"), and 20 min after meal initiation ("POST"). Blood glucose levels were measured every 30 min for a total of 240 min post-meal initiation. Mean blood glucose levels at 1 and 2 h after meal initiation, blood glucose area under the curve (AUC), and maximum blood glucose levels were analyzed. RESULTS: At both 60 and 120 min after meal initiation, the PRE arm showed significantly lower glycemic excursions than the START arm (P = 0.0029 and 0.0294, respectively) and the POST arm (P = 0.001 and 0.0408, respectively). Glycemic AUC was significantly less in the PRE arm versus both the START and POST arms (159.5 +/- 58.9 mg/dL vs. 187.0 +/- 43.1 mg/dL [P = 0.0297] and 184.5 +/- 33.2 mg/dL [P = 0.0463], respectively). Peak blood glucose levels were significantly lower in the PRE arm compared to the START arm (P = 0.0039) and the POST arm (P = 0.0027). CONCLUSIONS: A bolus of rapid-acting insulin 20 min prior to a meal results in significantly better postprandial glucose control than when the meal insulin bolus is given just prior to the meal or 20 min after meal initiation.

Prevention of nocturnal hypoglycemia using predictive alarm algorithms and insulin pump suspension.

OBJECTIVE: The aim of this study was to develop a partial closed-loop system to safely prevent nocturnal hypoglycemia by suspending insulin delivery when hypoglycemia is predicted in type 1 diabetes. RESEARCH DESIGN AND METHODS: Forty subjects with type 1 diabetes (age range 12-39 years) were studied overnight in the hospital. For the first 14 subjects, hypoglycemia (<60 mg/dl) was induced by gradually increasing the basal insulin infusion rate (without the use of pump shutoff algorithms). During the subsequent 26 patient studies, pump shutoff occurred when either three of five (n = 10) or two of five (n = 16) algorithms predicted hypoglycemia based on the glucose levels measured with the FreeStyle Navigator (Abbott Diabetes Care). RESULTS: The standardized protocol induced hypoglycemia on 13 (93%) of the 14 nights. With use of a voting scheme that required three algorithms to trigger insulin pump suspension, nocturnal hypoglycemia was prevented during 6 (60%) of 10 nights. When the voting scheme was changed to require only two algorithms to predict hypoglycemia to trigger pump suspension, hypoglycemia was prevented during 12 (75%) of 16 nights. In the latter study, there were 25 predictions of hypoglycemia because some subjects had multiple hypoglycemic events during a night, and hypoglycemia was prevented for 84% of these events. CONCLUSIONS: Using algorithms to shut off the insulin pump when hypoglycemia is predicted, it is possible to prevent hypoglycemia on 75% of nights (84% of events) when it would otherwise be predicted to occur.

A pilot trial of pramlintide home usage in adolescents with type 1 diabetes.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of home pramlintide use in adolescents with type 1 diabetes. PATIENTS AND METHODS: This was a randomized, 28-day pilot trial of pramlintide (maximum dose: 30 microg per meal) in 10 adolescents aged 13 to 17 years. End points included changes in hemoglobin A1c (HbA1c) values, body weight, and postprandial peak blood glucose levels and area under the curve on continuous glucose monitoring. RESULTS: Changes in HbA1c values, body weight, and total insulin dose declined in the treatment group compared with the control group (bootstrapped, P