title: A Simplified Semiquantitative Meal Bolus Strategy Combined with Single- and Dual-Hormone Closed-Loop Delivery in Patients with Type 1 Diabetes: A Pilot Study.
abstract: Single- and dual-hormone closed-loop systems can improve glycemic control and have the potential to reduce carbohydrate-counting burden for patients with type 1 diabetes; however, simplification of meal insulin calculation should not compromise glycemic control.
  
  
  
  We compared in a randomized outpatient pilot trial: (1) a single-hormone closed-loop system accompanied with carbohydrate-content matched boluses versus accompanied with a simplified meal bolus strategy, and (2) a dual-hormone closed-loop system accompanied with carbohydrate-content matched boluses versus accompanied with a simplified meal bolus strategy. Carbohydrate-matched boluses were based on the participant's carbohydrate meal content estimation whereas the simplified strategy involved the selection, by participants, of a semi-quantitative meal carbohydrate-content size: snack, regular, large, or very large meal. Each participant also underwent sensor-augmented pump therapy. Basal insulin delivery was more aggressive with the simplified bolus. The primary outcome was mean sensor glucose level over a 15-h daytime period.
  
  
  
  Twelve participants were recruited (48.2 ± 16.0 years old; HbA1c 7.4% ± 0.9%) to compare the two bolus strategies during single- and dual-hormone closed-loop delivery. A similar mean sensor glucose level (15 h) was achieved with the carbohydrate-matched boluses and simplified strategy using single-hormone (median [interquartile]: 7.6 [7.2-8.1] vs. 8.0 [7.0-8.6] mmol/L; P = 0.90) and dual-hormone closed-loop systems (7.6 [6.7-9.1] vs. 7.0 [6.4-8.2] mmol/L; P = 0.08). Exploratory analyses showed that, as compared with sensor-augmented pump therapy, there was an increased time spent in hypoglycemia with the simplified strategy but not with the carbohydrate-matched boluses.
  
  
  
  Though the algorithm employed in this pilot study may lead to an increased risk for hypoglycemia, this strategy has the potential to reduce the carbohydrate-counting burden in patients with type 1 diabetes while generally maintaining adequate glucose control. Longer outpatient studies with an improved algorithm are needed.
authors.affiliation: 1 Institut de Recherches Cliniques de Montréal , Montreal, Canada .|2 Department of nutrition, Université de Montréal , Montreal, Canada .
authors.forename: Véronique
authors.initials: V
authors.lastname: Gingras
authors.affiliation: 1 Institut de Recherches Cliniques de Montréal , Montreal, Canada .|3 Division of Experimental Medicine, McGill University , Montreal, Canada .
authors.forename: Ahmad
authors.initials: A
authors.lastname: Haidar
authors.affiliation: 1 Institut de Recherches Cliniques de Montréal , Montreal, Canada .
authors.forename: Virginie
authors.initials: V
authors.lastname: Messier
authors.affiliation: 4 Montreal Children's Hospital, McGill University Health Center , Montreal, Canada .
authors.forename: Laurent
authors.initials: L
authors.lastname: Legault
authors.affiliation: 5 Research Center of the Université de Montréal Hospital Center (CRCHUM) , Montreal, Canada .
authors.forename: Martin
authors.initials: M
authors.lastname: Ladouceur
authors.affiliation: 1 Institut de Recherches Cliniques de Montréal , Montreal, Canada .|2 Department of nutrition, Université de Montréal , Montreal, Canada .|3 Division of Experimental Medicine, McGill University , Montreal, Canada .|5 Research Center of the Université de Montréal Hospital Center (CRCHUM) , Montreal, Canada .|6 Montreal Diabetes Research Center (MDRC) , Montreal, Canada .
authors.forename: Rémi
authors.initials: R
authors.lastname: Rabasa-Lhoret
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use; D007332:Insulin Infusion Systems; D008297:Male; D062407:Meals; D010865:Pilot Projects; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin