Few studies have assessed the accuracy of the FreeStyle Libre Pro (FLP) continuous glucose monitor for estimating plasma glucose (PG) in non-diabetic children.
Objective
Determine the accuracy of FLP compared to PG during OGTT in healthy children.
Subjects
Children (7–11.99y) with healthy weight & overweight/obesity (n=33; 52% male).
Methods
Participants wore the FLP before and during a 2-hour OGTT; PG was measured at 30min intervals. Potential systematic- and magnitude-related biases for FLP vs. PG were examined.
Results
FLP 15-minute averages and PG were correlated at most timepoints during OGTT (r2=.35-.69, p’s<0.001 for time point 30–120minutes) and for PG area under the curve (AUC) (r2=0.65, p<0.0001). There were no systematic biases as assessed by Bland-Altman analyses for FLP AUC or for FLP at each OGTT timepoint. However, for fasting glucose, a significant magnitude bias was noted (r2=0.38, p<0.001), such that lower PG was underestimated, and higher PG was overestimated by FLP readings; further, there was poor correlation between fasting PG and FLP (r2=0.06, p=0.22). BMIz was also associated with FLP accuracy: FLP overestimated PG in children with low BMIz and underestimated PG in those with overweight/obesity for OGTT AUC and OGTT PG at baseline, 60, and 120 minutes (all p’s≤0.015). No adverse events occurred with FLP.
Conclusions
Among children without diabetes, the FLP was well tolerated and correlated with post-OGTT glucose, but had magnitude bias affecting fasting glucose and appeared to underestimate plasma glucose in those with overweight/obesity. These results suggest potential limitations for the utility of the FLP for research.