Diurnal variation in the association between the scan frequency of isCGM and CGM metrics: post hoc analysis of the ISCHIA study

Background and aims To investigate the association between the frequency of intermittent-scanning continuous glucose monitoring (isCGM) and diurnal variation of time in range (TIR), time above range (TAR), and time below range (TBR), we performed a post hoc analysis of the ISCHIA study, a multicenter, prospective, open-label, randomized crossover study of patients with type 1 diabetes mellitus. Method Data of 93 people who completed the ISCHIA study were used. We calculated scan frequency, TAR, TIR, and TBR of four approximately 6-h intervals: 6:00–11:59 (morning), 12:00–17:59 (afternoon), 18:00–23:59 (evening), and 0:00–5:59 (night). The correlation between scan frequency and diurnal variation of CGM metrics was analyzed using nonparametric Spearman correlation analysis. Results More frequent scanning was associated with higher TIR in the afternoon (rho = 0.343, P