Real-Time Continuous Glucose Monitoring Linked to Greater Reduction in HbA1c

Alexander Abitbol, MDCM

Adults with type 1 diabetes (T1D) who initiated real-time continuous glucose monitoring (CGM) had significantly greater reduction in HbA1c at 6 - 12 months compared with intermittently scanned CGM, according to new findings.

These patients additionally had significantly greater time in range, lower time below range, and lower glycemic variability compared to the matched cohort.

“Although both the real-time CGM and intermittently scanned CGM cohorts demonstrated clinically significant improvements in glycemic control from baseline, the superior glycemic control in the real-time CGM cohort may be due to the higher time in range, lower time below range, and lower glycemic variability, compared to the intermittently scanned CGM cohort,” wrote study author Alexander Abitbol, MDCM, LMC Diabetes & Endocrinology.

Although CGM has been reported to improve glycemic outcomes in patients with T1D, the real-world effectiveness of using real-time versus intermittently scanned CGM on HbA1c and CGM metrics has not been directly compared.

The retrospective, observational REAL-CGM-T1D explored these outcomes using data from the Canadian LMC Diabetes Registry. Patients were eligible for inclusion if they had a diagnosis of T1D >12 months, age ≥18 years, initiated a real-time CGM device or an intermittently scanned CGM, or maintained conventional self-measured blood glucose (SMBG) between January 2018 - December 2020.

The primary endpoint was HbA1c at 6 - 12 months in the matched real-time CGM and intermittently scanned CGM cohorts and in matched real-time CGM and SMBG cohorts. A multivariate linear regression model evaluated the primary outcome adjusting for baseline HbA1c as a covariate.

There were 187 real-time CGM and 230 intermittently scanned CGM patients eligible for matching. After propensity score matching, there were 143 patients in each cohort who were well-balanced on their baseline characteristics.

The mean follow-up period for HbA1c was 9.6 ± 2.2 months for the real-time CGM cohort and 9.9 ± 2.1 months for intermittently scanned CGM cohort.

Within the matched real-time CGM and intermittently scanned CGM cohorts, data show real-time CGM users had a significantly greater HbA1c benefit compared to intermittently scanned CGM users (adjusted difference, -3 mmol/mol [95% CI, -5 to -1]; -0.3% [95% CI, -0.5 to -0.1]; P = .01).

Among patients with baseline HbA1c <69 mmol/mol (8.5%), the real-time CGM cohort had a significantly greater reduction in HbA1c compared to the intermittently scanned CGM cohort (-4 mmol/mol [95% CI, -7 mmol/mol to -2 mmol/mol]; -0.4% [95% CI, -0.6% to -0.2%]; P <.001).

There was additionally a significantly greater HbA1c reduction at 6 - 12 months in patients using MDI therapy (-3 mmol/mol [95% CI, -6 mmol/mol to -0 mmol/mol]; -0.3% [95% CI, -0.5% to 0.0%]; P = .05).

Moreover, the real-time CGM cohort had a significantly greater time in range (58.3 ± 16.1% vs.  54.5 ± 17.1%, P = .03), lower time below range (2.1 ± 2.7% vs. 6.1 ± 5.0%, P <.001), and lower glycemic variability.

“The data from this study support the benefits and importance of real-time and predictive alerts for individuals with T1D,” Abitbol added.

The study, “Real-world glycemic outcomes in patients with type 1 diabetes using a real-time continuous glucose monitor compared to an intermittently scanned glucose monitor: a retrospective observational study from the Canadian LMC Diabetes Registry,” was published in Diabetic Medicine.