Impact of bedtime snack composition on prevention of nocturnal hypoglycemia in adults with type 1 diabetes undergoing intensive insulin management using lispro insulin before meals: a randomized, placebo-controlled, crossover trial.
OBJECTIVE
To determine the impact of four bedtime (HS) snack compositions on nocturnal glycemic control, including frequency of hypoglycemia (<4 mmol/l) and morning hyperglycemia (>10 mmol/l), in adults with type 1 diabetes using lispro insulin before meals and NPH insulin at bedtime.


METHODS
Substitutions of 15 g carbohydrate (one starch exchange) for an equivalent amount of uncooked cornstarch or pure protein were compared to a standard snack (control: two starch + one protein exchange) and to no snack (placebo) in 15 adults using a randomized, cross-over design. All snacks were equivalent in kcal, fat, and total available glucose. An intravenous facilitated hourly blood glucose sampling during the night (11:00 P.M. to 7:00 A.M.).


RESULTS
The glycemic level at bedtime (<7, 7-10, and >10 mmol/l) mediated the effects observed. A total of 14 hypoglycemic episodes, in 60% of patients, and 23 morning hyperglycemic episodes occurred over 50 nights. Most hypoglycemic episodes (10 of 14, 71%) occurred with no snack compared to any snack (P < 0.001) and at HS levels of <7 mmol/l (P = 0.05). The standard and protein snacks resulted in no nocturnal hypoglycemia at all HS glucose levels (P < 0.001). Only HS glucose >10 mmol/l was protective against hypoglycemia, even in the absence of a snack (P = 0.05); 46% of morning hyperglycemic episodes were associated (r = 0.37, P = 0.07) with this HS glucose level.


CONCLUSIONS
The need for and composition of an HS snack depends on the HS glucose such that no snack is necessary at levels >10 mmol/l. At levels between 7 and 10 mmol/l, any snack is advised, and at <7 mmol/l, a standard or protein snack is recommended.
Kalergis
Maria
M
McGill Nutrition Centre, Royal Victoria Hospital, MUHC, McGill University, Montreal, Quebec, Canada.
Schiffrin
Alicia
A
Gougeon
Réjeanne
R
Jones
Peter J H
PJ
Yale
Jean-François
JF
D000328:Adult; D000368:Aged; D001786:Blood Glucose; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000178:diet therapy* / Q000188:drug therapy*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004435:Eating; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000178:diet therapy / Q000188:drug therapy / Q000517:prevention & control*; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007328:Insulin / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D061268:Insulin Lispro; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007004:Hypoglycemic Agents; D007328:Insulin; D061268:Insulin Lispro