Sampling duration matters: Intraindividual variation of glycaemic metrics in type 1 diabetes using automated insulin delivery.

INTRODUCTION

Understanding intraindividual variability in glycaemic metrics among users of automated insulin delivery (AID) is essential for interpreting data from continuous glucose monitoring (CGM).

METHODS

CGM data over 56 days were collected from 142 individuals with type 1 diabetes using AID systems. Glycaemic metrics were derived from four 14-day periods and two 28-day periods.

RESULTS

The 95% limit of agreement for the difference between two measurements of time in range (TIR) from the same individual over 14-day periods was ±13.4%. The risk that two 14-day TIR values from the same individual differed by more than 5% points was 46.5%. If TIR was based on two 28-day periods, the 95% limit of agreement decreased to ±9.0%. The risk that two 28-day TIR values from the same individual differed by more than 5% points was 27.6%.

CONCLUSION

A 28-day CGM sampling period is recommended to minimise random variation and obtain more reliable glycaemic metrics.