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.