Abstract
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 (7-11.99 years) with healthy weight and overweight/obesity (n = 33; 52% male). METHODS: Participants wore the FLP before and during a 2-hour OGTT; PG was measured at 30 minutes 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 (r(2) = 0.35-0.69, P's < .001 for time point 30-120 minutes) and for PG area under the curve (AUC) (r(2) = 0.65, P < .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 (r(2) = 0.38, P < .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 (r(2) = 0.06, P = .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 ≤ .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.