title: Use of a food and drug administration-approved type 1 diabetes mellitus simulator to evaluate and optimize a proportional-integral-derivative controller.
abstract: BACKGROUND
  Clinical studies have shown that the Medtronic proportional-integral-derivative (PID) control with insulin feedback (IFB) provides stable 24 h glucose control, but with high postprandial glucose. We coupled this algorithm to a Food and Drug Administration-approved type 1 diabetes mellitus simulator to determine whether a proportional-derivative controller with preprogrammed basal rates (PDBASAL) would have better performance.
  
  
  METHODS
  We performed simulation studies on 10 adult subjects to (1) obtain the basal profiles for the PDBASAL controller; (2) define the pharmacokinetic/pharmacodynamic profile used to effect IFB, (3) optimize the PID and PDBASAL control parameters, (4) evaluate improvements obtained with IFB, and (5) develop a method to simulate changes in insulin sensitivity and assess the ability of each algorithm to respond to such changes.
  
  
  RESULTS
  PDBASAL control significantly reduced peak postprandial glucose [252 (standard error = 11) versus 279 (14) mg/dl; p < .001] and increased nadir glucose [102 (3) versus 92 (3) mg/dl; p < .001] compared with PID control (both implemented with IFB). However, with PDBASAL control, fasting glucose remained elevated following a 30% decrease in insulin sensitivity [156 (6) mg/dl; different from the target of 110 mg/dl; p < .001] and remained below target following a 30% increase in insulin sensitivity [84 (2) mg/dl; p < .001]. In both cases, PID control returned glucose levels to target.
  
  
  CONCLUSIONS
  PDBASAL provides better postprandial glucose control than PID but is not appropriate for subjects whose basal requirements change with insulin sensitivity. Simulations used to compare different control strategies should assess this variability.
authors.affiliation: DoD Biotechnology High-Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, MD 21702, USA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Laxminarayan
authors.forename: Jaques
authors.initials: J
authors.lastname: Reifman
authors.forename: Garry M
authors.initials: GM
authors.lastname: Steil
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001786:Blood Glucose / Q000032:analysis*; D003198:Computer Simulation; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy; D006801:Humans; D007332:Insulin Infusion Systems / Q000592:standards*; D008875:Middle Aged; D019518:Postprandial Period; D014481:United States; D014486:United States Food and Drug Administration; D055815:Young Adult
chemical_list: D001786:Blood Glucose