Three‐variate trajectories of metabolic control, body mass index, and insulin dose: Heterogeneous response to initiation of pump therapy in youth with type 1 diabetes

OBJECTIVE: Continuous subcutaneous insulin infusion (CSII) in youths with type 1 diabetes (T1D) is often associated with lower HbA1c, lower total daily insulin dose (TDD), and lower body mass index (BMI) compared with multiple daily injections (MDI). Individual responses to CSII are diverse. The aim was to identify unique three‐variate patterns of HbA1c, BMI standard deviation score (SDS), and TDD after switching to CSII. METHODS: Five thousand one hundred and thirty‐three youths (≤20 years; 48% boys; median age at pump start 12.5 years) with T1D duration ≥3 years at CSII initiation were selected from the multicenter DPV registry. We applied group‐based multitrajectory modeling to identify groups of individuals following similar trajectories. Measurements were aggregated quarterly during a 3‐year follow‐up period. Trajectory variables were changes of HbA1c, BMI‐SDS, and TDD from baseline (delta = quarterly aggregated values at each time point [i] minus the respective baseline value). RESULTS: Four groups of diverging Delta‐HbA1c, Delta‐BMI‐SDS, and Delta‐TDD patterns were identified. All showed improvements in HbA1c during the first 3 months. Group 1 (12%) was characterized by modest HbA1c increase thereafter, TDD reduction, and stable BMI‐SDS. In Group 2 (39%), increasing HbA1c, decreasing BMI‐SDS, and stable TDD were found. By contrast, sustainably improved HbA1c, increasing BMI‐SDS, and stable TDD were observed in Group 3 (32%). Group 4 (17%) was characterized by increasing levels for HbA1c, BMI‐SDS, and TDD. Between‐group differences in baseline HbA1c, BMI‐SDS, TDD as well as in sex ratio, age at diabetes onset and at pump start were observed. CONCLUSIONS: Definite trajectories of glycemic control, BMI, and TDD over 3 years after CSII initiation were identified in youths with T1D allowing a more personalized treatment recommendation.