Objective: This study was performed to understand and to compare differences in utilization of continuous glucose monitoring (CGM) and the rate of change (ROC) arrow to adjust insulin therapy among individuals with type 1 diabetes (T1D), comparing those treated with multiple daily insulin injections (MDI) with those treated with continuous subcutaneous insulin infusion (CSII).
Research design and methods: We surveyed 222 T1D individuals who regularly used real-time CGM to obtain information about general CGM use and response to glucose ROC arrows in managing their diabetes.
Results: The survey was completed by 222 T1D individuals. Respondents included CSII (n = 166) and MDI (n = 56) users. MDI and CSII respondents reported similar substantial increases in correction dosages (from 220 mg/dL to 120 mg/dL) in response to increasing glucose (one ROC arrow up: rising 2-3 mg/dL/min): +120% and +108%, respectively (P = 0.13). MDI and CSII respondents reported similar substantial increases in correction dosages in response to rapidly increasing glucose (two arrows up: rising >3 mg/dL/min): +146% and +138%, respectively (P = 0.72). When correcting from 220 mg/dL to 120 mg/dL, MDI respondents reported larger correction dosage reductions than CSII respondents in response to decreasing glucose (one ROC down arrow: decreasing 2-3 mg/dL/min) and rapidly decreasing glucose (two ROC down arrows: decreasing >3 mg/dL/min): -50% versus -37%, respectively (P = .024) and -52% versus 38%, respectively (P = 0.034). Similar between-group differences were observed in mealtime dosage adjustments.
Conclusions: CGM users often rely on ROC information when determining insulin doses and tend to make larger changes than current recommendations suggest regardless of insulin delivery method.