In the Journals

Acetaminophen falsely elevates continuous glucose monitor values

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August 17, 2015

Continuous glucose monitors may inaccurately indicate higher glucose levels when users take acetaminophen, according to recent study findings published in Diabetes Care.

“To better understand this effect, we performed an acetaminophen challenge as part of an outpatient study designed to investigate the potential challenges to closed-loop systems, which use [continuous glucose monitor] sensor glucose values to automate insulin delivery,” the researchers wrote.

David M. Maahs, MD, of the Barbara Davis Center for Childhood Diabetes at the University of Colorado, and colleagues evaluated 40 patients with diabetes (43% male; median age, 28.5 years; HbA1c, 7.3 ± 0.8%) to determine the effect of acetaminophen on continuous glucose monitor (CGM) glucose values compared with blood glucose meter values.

David Maahs

David M. Maahs

Participants using a Dexcom G4 CGM system ingested 1,000 mg acetaminophen at breakfast and obtained blood glucose meter readings at baseline, 0.5, 1, 2, 4, 6 and 8 hours. Researchers selected the blood glucose meter value closest to the target time but no more than 15 minutes from the target time. CGM values were adjusted for baseline.

Significant differences in values were found 8 hours after ingestion of acetaminophen (P .01 for all). Overall, the greatest mean difference was 61 mg/dL at 120 minutes (blood glucose meter, 171 mg/dL).

Blood glucose meter values of less than 70 mg/dL were found in three participants with higher CGM glucose readings. CGM glucose values greater than 180 mg/dL and blood glucose meter values of more than 100 mg/dL lower were found among 10 participants.

“Acetaminophen falsely elevates CGM glucose values compared with [blood glucose] meter values,” the researchers wrote. “These data have implications for use of CGM glucose as a replacement for meter glucose for diabetes decision making and for closed-loop systems using CGM glucose values for automated insulin delivery.” – by Amber Cox

Disclosure: Maahs reports being on the advisory board for Insulet. Please see the full report for a list of all other researchers’ financial disclosures.