903-P: Hydroxyurea Resulting in False Elevation of Continuous Glucose Sensor Values

Objective: To assess the degree, duration, and mean absolute relative difference (MARD) of false values per continuous glucose monitoring (CGM) systems when hydroxyurea (HU) is administered.

Research Design and Methods: Inpatient glucometer and CGM data from 16 post-total pancreatectomy (TPIAT) patients using Dexcom Professional G4 and 6 patients using Dexcom G6 were analyzed after daily dosing with HU. Timing of HU dosing and up to 2 weeks of sensor and glucometer values were assessed in each patient.

Results: A false elevation (>20 mg/dL) of sensor readings were identified after HU dosing. The greatest discrepancy between glucometer and sensor readings occurred 0.5-2 hours after HU administration [G4 (mean 53 mg/dL, median 44 mg/dL, MARD 0.55), G6 (mean 67 mg/dL, median 72.5 mg/dL, MARD 0.79)]. The sensor and glucometer readings were <20 mg/dL mean and median, MARD 0.14 (G4) and <40mg/dL mean and median, MARD 0.18 (G6), by 6 hours after administration. All other prescribed medications were given multiple times each day and did not result in glucose value discrepancy.

Conclusions: There is a false elevation of sensor glucose readings compared to glucometer values (up to 180 mg/dL (G4), 235 mg/dL (G6)) from 0.5hr to 6hr following HU administration. It is important to counsel a patient using a Dexcom CGM system and HU therapy on this finding and to advise reliance on glucometer testing for accurate glucose assessment up to 6 hours after HU administration.