Evaluation of an Objective Measure of Mealtime Insulin Administration Frequency in Emerging Adults with Type 1 Diabetes

Objective measures of self-management are critical for understanding glycemic outcomes in individuals with type 1 diabetes (T1D). The mealtime insulin bolus score (BOLUS), derived from insulin pump data, is a validated indicator of mealtime insulin engagement in pediatric T1D populations, but its validity in emerging adults (EA) is unknown. We examined associations between BOLUS scores and glycemic outcomes (HbA1c and continuous glucose monitoring metrics) in 347 EA with T1D (ages 18–22). Higher BOLUS scores were associated with lower HbA1c ( r = −0.24, P < 0.001), greater time in range ( r = 0.23, P < 0.001), and lower time above range ( r = −0.23, P < 0.001). The mean BOLUS score (1.17) was substantially lower than the previously reported mean pediatric BOLUS score. Findings support the validity of BOLUS as an objective behavioral measure in EA with T1D and highlight reduced mealtime insulin engagement during this developmental period.