Calculating the insulin to carbohydrate ratio using the hyperinsulinaemic-euglycaemic clamp-a novel use for a proven technique.
BACKGROUND
In patients with type 1 diabetes, three main variables need to be assessed to optimize meal-related insulin boluses: pre-meal blood glucose (BG), insulin to carbohydrate ratio (I : C), and basal insulin. We are presenting data for a novel use of the hyperinsulinaemic-euglycaemic clamp (HEC) in patients with type 1 diabetes that minimizes the impact of these variables and can be used to determine the I : C.


METHODS
Ten subjects (six men and four women) using continuous subcutaneous insulin infusion (CSII) pumps were recruited for this study [24-65 years; BMI 27.1 +/- 4.9 kg/m(2); A1C 7.2 +/- 1.4% (mean +/- SD)]. The HEC used a primed continuous intravenous insulin infusion of 40 mU/m(2)/min and a variable infusion of 20% glucose to maintain BG at 90 mg/dL. After subjects were in steady state (SS) for 50 min, a standardized meal (40% of total calories/day - 30% carbohydrate, 30% protein, 40% fat) was consumed. Subjects gave the insulin bolus with their CSII pump. No changes were made in the glucose infusion rate.


RESULTS
Mean BG at SS was 85.7 +/- 10.4 mg/dL. Peak BG was 115.0 +/- 12.7 mg/dL at 68.5 +/- 8.8 min after the meal. Mean I : C was 1 : 9.3 +/- 1.7 (range 1 : 7-1 : 12). Insulin sensitivity varied from 1.9 to 9.1 mg/kg/min.


CONCLUSIONS
The HEC can be used to reduce confounding factors and to determine the I : C. As a first estimate of the I : C in patients with type 1 diabetes, it is recommended to start with a ratio of 1 : 9.3 and to measure post-prandial BG at 70 min.
Bevier
Wendy C
WC
Sansum Diabetes Research Institute, Santa Barbara, CA 93105, USA.
Zisser
Howard
H
Palerm
Cesar C
CC
Finan
Daniel A
DA
Seborg
Dale E
DE
Doyle
Francis J
FJ
Wollitzer
Alison Okada
AO
Jovanovic
Lois
L
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D015309:Glucose Clamp Technique; D006706:Homeostasis; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D015918:Infusion Pumps, Implantable; D007328:Insulin / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D007332:Insulin Infusion Systems; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin