Impact of overnight glucose on next-day functioning in adults with type 1 diabetes: An exploratory intensive longitudinal study

Objective: While there is evidence that functioning, or ability to perform daily life activities, can be adversely influenced by type 1 diabetes, the impact of acute fluctuations in glucose levels on functioning is poorly understood. 

Research Design and Methods: Using dynamic structural equation modeling, we examined whether overnight glucose (CV, % time <70 mg/dL, % time >250 mg/dL) predicted 7 next-day functioning outcomes (mobile cognitive tasks, accelerometry-derived physical activity, self-reported activity participation) in adults with type 1 diabetes. We examined mediation, moderation, and whether short-term relationships were predictive of global patient-reported outcomes.

Results: Overall next-day functioning was significantly predicted from overnight CV (p=0.017) and % time >250 mg/dL (p=0.037). Pairwise tests indicated that higher CV was associated with poorer sustained attention (p=0.028) and lower engagement in demanding activities (p=0.028); time <70 mg/dL was associated with poorer sustained attention (p=0.007); and time >250 mg/dL was associated with more sedentary time (p=0.024). The impact of CV on sustained attention was partially mediated by sleep fragmentation. Individual differences in the effect of overnight time <70 mg/dL on sustained attention predicted global illness intrusiveness (p=0.016) and diabetes-related quality of life (p=0.036).

Conclusions: Overnight glucose predicts problems with objective and self-reported next-day functioning, and can adversely impact global patient-reported outcomes. These findings across diverse outcomes highlight the wide-ranging effects of glucose fluctuations on functioning in adults with type 1 diabetes.