Predictors of the effectiveness of isCGM usage in adults with type 1 diabetes mellitus: post-hoc analysis of the ISCHIA study

Aim: The Effect of Intermittent-Scanning Continuous Glucose Monitoring to Glycemic Control Including Hypoglycemia and Quality of Life of Patients with Type 1 Diabetes Mellitus (ISCHIA) study was a randomized, crossover trial that reported the decrease in time below range (TBR) by the use of intermittent-scanning continuous glucose monitoring (isCGM) combined with structured education in adults with type 1 diabetes (T1D) treated by multiple daily injections. The participants were instructed to perform frequent scanning of the isCGM sensor (10 times a day or more) and ingest sugar when impending hypoglycemia is suspected by tracking the sensor glucose levels and the trend arrow. We conducted post-hoc analysis to identify factors affecting difference in TBR (∆TBR), in time in range (∆TIR), and in time above range (∆TAR). Participants and methods: Data from 93 participants who completed the ISCHIA study were used. Multiple regression analyses were performed to identify factors affecting CGM metrics. Results: Pearson’s correlation analysis showed the negative association between log-transformed scan frequency and with ∆TBR (r = − 0.255, P = 0.015), while there was no significant association of log-transformed scan frequency with ∆TIR (r = 0.172, P = 0.102) and ∆TAR (r = 0.032, P = 0.761), respectively. The log-transformed scan frequency was an independent predictor of ∆TBR (Beta = − 7.712, P = 0.022), but not of ∆TIR(Beta = 7.203, P = 0.091) and of ∆TAR (Beta = 0.514, P = 0.925). Conclusions: Our findings suggest that more frequent scanning of isCGM may be beneficial to reduce TBR in T1D adults.