Bedtime Snack Composition and Overnight Glycemic Profiles in Children and Adolescents with Type 1 Diabetes Using Multiple Daily Injections: A Randomized Crossover Study.

Background/

Objectives

Bedtime snacks are frequently used in youth with type 1 diabetes (T1D) to reduce nocturnal hypoglycemia risk; however, the optimal macronutrient composition remains uncertain, particularly in those treated with multiple daily injections (MDI). This randomized crossover study evaluated whether standardized whole-food bedtime snacks with different macronutrient profiles yield distinct overnight continuous glucose monitoring (CGM) patterns.

Methods

Twelve children and adolescents with T1D using glargine/lispro-based MDI completed four bedtime snack protocols: carbohydrate-only (CHO), carbohydrate-plus-protein (CHO + PRO), carbohydrate-plus-fat (CHO + FAT), and carbohydrate-plus-fiber (CHO + FIB). Each snack was consumed for three consecutive nights at 21:00 without additional bolus insulin. Blinded CGM data were analyzed for 21:00-09:00 and for predefined postprandial intervals. Because no a priori sample size calculation was performed, the study was conducted as an exploratory pilot trial. Nights per snack were averaged before within-subject comparisons.

Results

Overnight time in range (TIR; 70-180 mg/dL) varied across protocols (p = 0.014), with the highest TIR following CHO + PRO (85.8% ± 12.1%) and the lowest following CHO + FAT (70.9% ± 19.1%); however, adjusted whole-night pairwise comparisons were not statistically significant. Differences were more pronounced during the first 6 h following snack consumption, when CHO + PRO was associated with higher TIR than CHO + FAT (91.2% ± 7.6% vs. 71.4% ± 20.8%; adjusted p = 0.011). Moreover, CHO + PRO was associated with lower peak-to-nadir glucose amplitude than CHO + FAT (88.1 ± 24.9 vs. 123.9 ± 36.5 mg/dL; adjusted p = 0.041). Hypoglycemic and hyperglycemic event rates did not significantly differ across protocols.

Conclusions

In children and adolescents with T1D using MDI, bedtime snack composition was associated with differences in early nocturnal glycemic stability. CHO + PRO demonstrated higher early night TIR and lower glucose amplitude than CHO + FAT; however, event-based safety outcomes did not significantly differ. Because only two pairwise comparisons remained significant after correction for multiple testing and the four snacks were not matched for energy content, these findings should be regarded as preliminary and hypothesis-generating; in particular, they do not demonstrate that any snack composition protects against nocturnal hypoglycemia. Confirmation is required in larger, adequately powered studies that include energy-matched snacks and a no-snack control condition.