450 Efficacy and feasibility of fully automated closed loop insulin pump therapy after islet auto-transplantation
Tuesday November 17, 2015 from 11:00 to 12:30
Plenary Room 1

Melena D Bellin, United States

Assistant Professor

Pediatric Endocrinology

University of Minnesota


Efficacy and feasibility of fully automated closed loop insulin pump therapy after islet auto-transplantation

Gregory Forlenza2, Gregory Beilman1, Ty B Dunn1, Brandon Nathan2, Srinath Chinnakotla1,2, Timothy L Preutt1, Antoinette Moran2, Melena Bellin1,2.

1Surgery, University of Minnesota, Minneapolis, MN, United States; 2Pediatrics, University of Minnesota, Minneapolis, MN, United States

Background: Total pancreatectomy with islet auto-transplantation (TPIAT) may be performed for patients with unrelenting chronic pancreatitis to relieve pain while minimizing the risk of diabetes.  Avoidance of hyperglycemia is essential after TPIAT to minimize beta cell apoptosis during islet engraftment.  Closed loop (CL) therapy has never previously been investigated in islet transplant recipients, but CL devices may improve glycemic control within a narrow therapeutic target.  In CL therapy, an insulin pump is paired with a continuous glucose monitor (CGM) and insulin delivery is adjusted automatically based on CGM values. Our objective was to determine the feasibility and efficacy of CL therapy to maintain near-normoglycemia following TPIAT. 
Methods:  We studied 14 participants post-TPIAT (36% male; mean age 35.9±11.4 years-old).  At the time of transition from intravenous to subcutaneous insulin (6±1.4 days after TPIAT), subjects were block randomized to subcutaneous insulin via a CL pump (n=7) or multiple daily injections (n=7) for 72 hours.  In both groups continuous glucose was monitored by CGM and reference glucose was measured by YSI every 4 hours for between-group comparison.
Results: Mean serum glucose values were significantly lower in the experimental group than in the control group (111±4 mg/dL v. 130±13 mg/dL; p=0.003).  There was a general trend in the proposed direction for lower glycemic variability based on standard deviation (14.1±3.3 mg/dL v. 21.0±10.2 mg/dL; p=0.115), AUC in hypoglycemia (146±270 v. 1615±4267 min*mg/dL; p=0.38), and AUC in hyperglycemia (2025±1177 v. 7860±11444 min*mg/dL; p=0.20) for the CL group compared to the control group.  There was also a trend towards greater percent time in the target range of 70-140 mg/dL for the CL group compared to the control group (89.2 v 70.6%; p=0.07).  Importantly, hypoglycemia was not increased in the CL group, despite the lower mean glucose.  An unexpected interaction was observed between study group assignment and islet mass transplanted:  islet mass impacted mean serum glucose in the control group (lower islet mass was associated with higher mean glucose), but CL therapy maintained BG in target range regardless of islet mass.
Conclusions: Results from this study show that CL therapy is superior to conventional therapy in maintaining euglycemia without increased hypoglycemia.  This technology shows significant promise as a tool to maintain strict euglycemic targets and minimize hypoglycemia after TPIAT.

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