Artificial Pancreas Using a Personalized Rule-Based Controller Achieves Overnight Normoglycemia in Patients With Type 1 Diabetes

Diabetes Technol Ther. 2014 Mar;16(3):172-9. doi: 10.1089/dia.2013.0229. Epub 2013 Oct 23.


Objective: This study assessed the efficacy of a closed-loop (CL) system consisting of a predictive rule-based algorithm (pRBA) on achieving nocturnal and postprandial normoglycemia in patients with type 1 diabetes mellitus (T1DM). The algorithm is personalized for each patient's data using two different strategies to control nocturnal and postprandial periods.

Research design and methods: We performed a randomized crossover clinical study in which 10 T1DM patients treated with continuous subcutaneous insulin infusion (CSII) spent two nonconsecutive nights in the research facility: one with their usual CSII pattern (open-loop [OL]) and one controlled by the pRBA (CL). The CL period lasted from 10 p.m. to 10 a.m., including overnight control, and control of breakfast. Venous samples for blood glucose (BG) measurement were collected every 20 min.

Results: Time spent in normoglycemia (BG, 3.9-8.0 mmol/L) during the nocturnal period (12 a.m.-8 a.m.), expressed as median (interquartile range), increased from 66.6% (8.3-75%) with OL to 95.8% (73-100%) using the CL algorithm (P<0.05). Median time in hypoglycemia (BG, <3.9 mmol/L) was reduced from 4.2% (0-21%) in the OL night to 0.0% (0.0-0.0%) in the CL night (P<0.05). Nine hypoglycemic events (<3.9 mmol/L) were recorded with OL compared with one using CL. The postprandial glycemic excursion was not lower when the CL system was used in comparison with conventional preprandial bolus: time in target (3.9-10.0 mmol/L) 58.3% (29.1-87.5%) versus 50.0% (50-100%).

Conclusions: A highly precise personalized pRBA obtains nocturnal normoglycemia, without significant hypoglycemia, in T1DM patients. There appears to be no clear benefit of CL over prandial bolus on the postprandial glycemia.

Trial registration: NCT01614496.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Blood Glucose / metabolism
  • Blood Glucose Self-Monitoring*
  • Cross-Over Studies
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 1 / physiopathology
  • Female
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Hypoglycemia / drug therapy*
  • Hypoglycemia / metabolism
  • Hypoglycemia / physiopathology
  • Hypoglycemic Agents / administration & dosage*
  • Infusions, Subcutaneous
  • Insulin / administration & dosage*
  • Insulin Infusion Systems*
  • Male
  • Meals
  • Pancreas, Artificial*
  • Postprandial Period
  • Predictive Value of Tests
  • Reproducibility of Results
  • Time Factors
  • Treatment Outcome


  • Blood Glucose
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Insulin
  • hemoglobin A1c protein, human

Associated data