We examined how glucose measurement intervals influence glycemic variability (GV) values. In this cross-sectional study, we analyzed 24-h sensor glucose levels (SG) measured during hospitalization using a continuous glucose monitor (iPro2) in 96 patients with type 2 diabetes. GV was calculated from SG values extracted every 5 min × the divisors of 288 (excluding 10, 360, 480, 720, 1440 minutes). Because mean glucose level (Mean) values are influenced more from extraction start time as extraction intervals increase, to maximumly reduce that influence, at first, the 96 patients were ranked from “1” (highest Mean) to “96” (lowest Mean) according their individual Mean values. Then, we delayed the extraction start time every 15 min in the following order: “96,” “2,” “95”⋯ “48,” “49,” from 00:00 of “1.” In the percentage of time in range (70-180 mg/dL) [TIR 70-180], Mean, standard deviation (SD), and coefficient of variation (CV), the values were numerically almost equal in every extraction. The mean absolute glucose (MAG) and glycemic variability percentage (GVP) became lower as extraction intervals increased. Extraction every 240 min showed a correlation coefficient to measurement every 5 min (r to 5 min) of about 0.9 for TIR 70-180, Mean, SD, and CV. Extraction every 60 min had an r to 5 min of about 0.9 for MAG and GVP (Table). Theoretically, for TIR 70-180, SD, and CV, measurements performed every 4 hours may maintain an r to 5 min of about 0.9.
S. Takeishi: None. H. Tsuboi: None.