The following is the summary of “Relationship Between Daytime Versus Nighttime Continuous Glucose Monitoring Metrics with A1C in Adults with Type 1 Diabetes” published in the December 2022 issue of Diabetes technology and therapeutics by Shah, et al.
The purpose of this study was to compare the effects of continuous glucose monitoring (CGM) readings taken during the day and at night on hemoglobin A1c levels in persons with type 1 diabetes (T1D). CGM data from 407 persons with T1D (age =39.15 years, duration=20 ± 12 years, A1C =7.3%± 1.4%, and 53% female) from trial 2 were included in this analysis. Furthermore, within 5 A1C categories (7%, 7%-7.9%, 8%-8.9%, 9%-9.9%, and ≥10%), the correlation between daytime (6 AM-10.59 PM) and nighttime (11 PM-5:59 AM) CGM variables like mean glucose, time in range (TIR; 70-180 mg/dL), and time in tight target range (TTIR; 70-140 mg/dL), and time above range (TAR >180 mg/dL) was investigated.
Even though mean glucose was rising with increasing A1C, there was no statistically significant difference between daytime and nighttime glucose levels in any of the five A1C groups (143.2 ± 22.7 vs. 143.6 ± 25.0 for A1C <7%, 171.4 ± 17.3 vs. 175.3 ± 28.8 for A1C 7.0%–7.9%, 193.4 ± 19.4 vs. 195.3 ± 29.5 for A1C 8.0%–8.9%, 214.9 ± 28.8 vs. 219.7 ± 36.1 for A1C 9.0%–9.9% and 244.0 ± 39.0 vs. 239.9 ± 50.9 for A1C ≥10%, P > 0.05). Similarly, within each of the 5 A1C groups, daytime and overnight CGM measures did not change.
The mean glucose, TIR, TTIR, and TAR during the day versus the night and the differences between the 5 A1C groups were not statistically significant (all P> 0.05). Adults with type 1 diabetes are just as responsive to glycemic control during the day as they are at night in terms of their A1C levels.