title: Comparison of Subcutaneous Regular Insulin and Lispro Insulin in Diabetics Receiving Continuous Nutrition: A Numerical Study.
abstract: BACKGROUND
  Optimal management of non-critically ill patients with diabetes maintained on continuous enteral feeding (CEN) is poorly defined. Subcutaneous (SQ) lispro and SQ regular insulin were compared in a simulated type 1 and type 2 diabetic patient receiving CEN.
  
  
  METHODS
  A glucose-insulin feedback mathematical model was employed to simulate type 1 and type 2 diabetic patients on CEN. Each patient received 25 SQ injections of regular insulin or insulin lispro, ranging from 0-6 U. Primary endpoints were the change in mean glucose concentration (MGC) and change in glucose variability (GV); hypoglycemic episodes were also reported. The model was first validated against patient data.
  
  
  RESULTS
  Both SQ insulin preparations linearly decreased MGC, however, SQ regular insulin decreased GV whereas SQ lispro tended to increase GV. Hourly glucose concentration measurements were needed to capture the increase in GV. In the type 2 diabetic patient, "rebound hyperglycemia" occurred after SQ lispro was rapidly metabolized. Although neither SQ insulin preparation caused hypoglycemia, SQ lispro significantly lowered MGC compared to SQ regular insulin. Thus, it may be more likely to cause hypoglycemia. Analyses of the detailed glucose concentration versus time data suggest that the inferior performance of lispro resulted from its shorter duration of action. Finally, the effects of both insulin preparations persisted beyond their duration of actions in the type 2 diabetic patient.
  
  
  CONCLUSIONS
  Subcutaneous regular insulin may be the short-acting insulin preparation of choice for this subset of diabetic patients. Clinical trial is required before a definitive recommendation can be made.
authors.affiliation: Department of Trauma and Critical Care Surgery, San Antonio Military Medical Center, Fort Sam Houston, TX, USA mamiestull@gmail.com.
authors.forename: Mamie C
authors.initials: MC
authors.lastname: Stull
authors.affiliation: Department of Trauma and Critical Care Surgery, San Antonio Military Medical Center, Fort Sam Houston, TX, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Strilka
authors.affiliation: Department of Trauma and Critical Care Surgery, San Antonio Military Medical Center, Fort Sam Houston, TX, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Clemens
authors.affiliation: Division of Trauma, Acute Care and Critical Care Surgery, Pennsylvania State College of Medicine, Hershey, PA, USA.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Armen
mesh_terms: D001786:Blood Glucose / Q000032:analysis; D003198:Computer Simulation; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004750:Enteral Nutrition; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007279:Injections, Subcutaneous; D007328:Insulin / Q000008:administration & dosage*; D061268:Insulin Lispro / Q000008:administration & dosage*; D008962:Models, Theoretical
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D061268:Insulin Lispro
keywords: computer simulation; diabetes; glucose variability; hyperglycemia; hypoglycemia; subcutaneous insulin