Impact of High-Dose Intravenous Vitamin C for Treatment of Sepsis on Point-of-Care Blood Glucose Readings

Background: Intravenous vitamin C therapy has been associated with reduced mortality in patients with sepsis. Of potential concern with this therapy are falsely elevated point-of-care (POC) blood glucose values vs laboratory analyzed (LA) readings. The purpose of this study was to compare POC and LA blood glucose measurements in patients receiving intravenous vitamin C therapy. Methods: All adults (>= 18 years old) admitted from January 2017 to December 2018 who received at least two doses of intravenous vitamin C and had at least one paired blood glucose collection were eligible for inclusion. The primary endpoint was the accuracy in paired blood glucose values determined using the International Organization for Standardization (ISO) 15197:2013 criteria. Paired values were assessed for clinical impact using the Parkes consensus error grid analysis. A subgroup analysis was conducted to determine the impact of impaired renal function on outcomes. Results: Fourteen patients were included for analysis with 46 paired blood glucose levels. Compliance with ISO15197:2013 criteria was met in 34 (73.9%) paired values, which did not meet the minimum criteria for accuracy. Subgroup analysis showed that the paired values from patients with impaired renal function did not meet the minimum requirements for compliance, while those from patients without impaired renal function did. The Parkes error grid showed that the variation in POC measurements likely had minimal clinical impact. Conclusions: Our study suggests that most patients receiving vitamin C for sepsis may still be monitored at POC with the glucose meter used in our study with minimal clinical impact.