Automatic Detection and Estimation of Unannounced Meals for Multivariable Artificial Pancreas System

Diabetes Technol Ther. 2018 Mar;20(3):235-246. doi: 10.1089/dia.2017.0364. Epub 2018 Feb 6.


Background: Automatically attenuating the postprandial rise in the blood glucose concentration without manual meal announcement is a significant challenge for artificial pancreas (AP) systems. In this study, a meal module is proposed to detect the consumption of a meal and to estimate the amount of carbohydrate (CHO) intake.

Methods: The meals are detected based on qualitative variables describing variation of continuous glucose monitoring (CGM) readings. The CHO content of the meals/snacks is estimated by a fuzzy system using CGM and subcutaneous insulin delivery data. The meal bolus amount is computed according to the patient's insulin to CHO ratio. Integration of the meal module into a multivariable AP system allows revision of estimated CHO based on knowledge about physical activity, sleep, and the risk of hypoglycemia before the final decision for a meal bolus is made.

Results: The algorithm is evaluated by using 117 meals/snacks in retrospective data from 11 subjects with type 1 diabetes. Sensitivity, defined as the percentage of correctly detected meals and snacks, is 93.5% for meals and 68.0% for snacks. The percentage of false positives, defined as the proportion of false detections relative to the total number of detected meals and snacks, is 20.8%.

Conclusions: Integration of a meal detection module in an AP system is a further step toward an automated AP without manual entries. Detection of a consumed meal/snack and infusion of insulin boluses using an estimate of CHO enables the AP system to automatically prevent postprandial hyperglycemia.

Keywords: Artificial pancreas; Fuzzy estimation.; Meal detection; Meal size estimation; Qualitative representation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Blood Glucose / analysis*
  • Blood Glucose Self-Monitoring
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Female
  • Humans
  • Hypoglycemia / prevention & control*
  • Hypoglycemic Agents / administration & dosage*
  • Insulin / administration & dosage*
  • Male
  • Meals*
  • Pancreas, Artificial*
  • Postprandial Period
  • Retrospective Studies
  • Treatment Outcome
  • Young Adult


  • Blood Glucose
  • Hypoglycemic Agents
  • Insulin