Continuous Glucose Monitoring

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Effects of Continuous Glucose Monitoring on Metrics of Glycemic Control in Diabetes: A Systematic Review With Meta-analysis of Randomized Controlled Trials


Key Takeaway: A recent systematic review and meta-analysis of 15 randomized controlled trials involving 2,461 patients showed greater improvement in mean hemoglobin A1c, time in target range, and time above range with use of real-time continuous glucose monitoring as compared to intermittently scanned continuous glucose monitoring.

A Randomized Trial of Closed-Loop Control in Children with Type 1 Diabetes


Key Takeaway: In a 16-week trial funded by the NIDDK and Tandem Diabetes Care, 101 children ages 6-13 with type 1 diabetes were randomized to a closed-loop system of insulin delivery (n=78) or the control group (n=23) where patients used a sensor-augmented insulin pump.  Children using the closed-loop system, consisting of a t:slim X2 insulin pump with Control-IQ  technology and a Dexcom G6 CGM, saw a significant time in range (TIR) improvement (target 70-180 mg/dL) from 53% at baseline to 67% (equivalent to 3.4 more hours per day; p<0.001) at the end of the study.  The control group saw a smaller TIR increase from 51% at baseline to 55% at the end of the study.  Notably, TIR increased most significantly overnight with children reaching 80% overnight TIR compared to 54% in the control group.  The treatment effect was evident in the first month and appeared consistent over 4 months.  Control-IQ technology demonstrated benefits across a broad range of baseline characteristics and proved easy to use for children and their parents.

Effect of Continuous Glucose Monitoring on Glycemic Control in Adolescents and Young Adults With Type 1 Diabetes

Source: Journal of the American Medical Association

Key Takeaway: Six-month, multicenter, randomized controlled trial using the Dexcom G5. The baseline population had diverse racial/ethnic backgrounds (38% Hispanic or non-white), high baseline HbA1c levels, and 41% had public health insurance. The trial showed a 0.4% A1c advantage in favor of CGM over BGM (p=0.01; baseline: 8.9%). Moreover, more than twice as many in the CGM group as compared to the BGM group achieved an A1c reduction ≥0.5% (44% vs. 21%, p=0.005) and over four-times as many participants in the CGM group vs. the BGM group saw an A1c reduction of ≥1% (25% vs. 6%, p=0.003). The CGM group also saw a 1.7 hour/day advantage vs. BGM on time-in-range (70-180 mg/dl) (p<0.001). Over two-thirds of the CGM group were using CGM at least five days/week by the end of the six-month study – the highest CGM use observed for adolescents in a study to date. Moreover, the CGM group reported significantly higher glucose monitoring satisfaction, measured via the Glucose Monitoring Satisfaction Survey score, at 26 weeks than the BGM group . Newer models of CGM devices that eliminate fingerstick calibration should lead to improved wearability and glycemic control even beyond the measured benefits observed in this trial. Improved glycemic control early in diabetes duration may prevent diabetes complications later in adulthood, making CGM an attractive option for this population.

Effect of Continuous Glucose Monitoring on Glycemic Control in Adolescents and Young Adults With Type 1 Diabetes Graph

Effect of Continuous Glucose Monitoring on Hypoglycemia in Older Adults With Type 1 Diabetes A Randomized Clinical Trial

Source: Journal of the American Medical Association

Key Takeaway:Older populations are more prone than younger populations to severe hypoglycemic episodes, which in turn contribute to dementia, risk of falls, glycemic variability, and mortality. To study whether CGM could reduce hypoglycemia incidence, Pratley and colleagues performed a randomized clinical trial that compared the effect of CGM (n = 103) with BGM (n = 100) in older adults (median age, 68 years) with type 1 diabetes in 22 diabetes centers across the US. The primary outcome was reduction in hypoglycemia (glucose <70mg/dL) over 6 months. Results showed that the median time in hypoglycemia was reduced from 73 minutes to 39 minutes per day in the CGM group compared with no change (from 68 minutes to 70 minutes per day) in the BGM group, an adjusted between group reduction of 27 minutes per day (95% CI, −40 to −16 min/d). Additionally, the median percentage of time with blood glucose levels below the range for severe hypoglycemia (glucose <54mg/dL) reached the goal per international guidelines (<14min/d in older adults). Moreover, only 1 severe hypoglycemic event (glucose <54mg/dL) occurred in the CGM group vs 10 in the BGM group, with 5 of those events involving seizure or loss of consciousness. 83% of participants in the CGM group used CGM at least 6 days per week during month 6 and the results did not differ by level of cognitive impairment, education level, or age. In summary, CGM reduced the time spent in the severe hypoglycemic range, which has health care use, mortality, morbidity, and economic benefits.

Effect of Continuous Glucose Monitoring on Hypoglycemia in Older Adults With Type 1 Diabetes Graph

Real Time CGM Studies: Effect of Continuous Glucose Monitoring on Glycemic Control in Adults with Type 1 Diabetes Using Insulin Injections – The DIAMOND Randomized Clinical Trial

Source: Journal of the American Medical Association

Key Takeaway: In the DIAMOND RCT, patients using multiple daily injections of insulin with type 1 diabetes who were randomly assigned to real-time CGM (rtCGM) had improved glycemic control vs. the SMBG group. This benefit was seen across patient groups regardless of baseline A1C, age, education level, or math ability. In addition, the rtCGM group spent 79% less time in nocturnal hypoglycemia, and also demonstrated a greater increase in hypoglycemic confidence and a greater decrease in diabetes distress vs. the SMBG group.

Baseline Glycated Hemoglobin Values Predict the Magnitude of Glycemic Improvement in Patients with Type 1 and Type 2 Diabetes: Subgroup Analyses from the DIAMOND Study Program

Source: Diabetes Technology & Therapeutics

Key Takeaway: Among the real-time CGM (rtCGM) users, the change in HbA1c was greatest in the highest HbA1c subgroup with similar decreases seen in both the T1D and T2D groups. Notably, adherence remained high in those with baseline HbA1c > 9% and the improvements seen were achieved without the need for additional medications. Thus, the costs of rtCGM in patients with high HbA1c may be offset by avoiding treatment intensification and the longer-term savings achieved by lowering HbA1c levels in poorly controlled diabetes populations.

Continuous Glucose Monitoring vs Conventional Therapy for Glycemic Control in Adults with Type 1 Diabetes Treated with Multiple Daily Insulin Injections – The GOLD Randomized Clinical Trial

Source: Journal of the American Medical Association

Key Takeaway: In the GOLD trial, glycemic control was improved with use of rtCGM compared with conventional treatment; however, increases in A1C and hypoglycemic events occurred when patients reverted back to SMBG during the crossover/washout period, suggesting that the effectiveness of CGM depends on uninterrupted use during treatment with MDI. Additionally, the study showed reductions in severe and nocturnal hypoglycemia as well as in glycemic variability and improved hypoglycemic confidence for rtCGM users.

Glycemic Outcomes in Adults With T1D Are Impacted More by Continuous Glucose Monitoring Than by Insulin Delivery Method: 3 Years of Follow-Up From the COMISAIR Study

Source: Diabetes Care

Key Takeaway: The COMISAIR study is the longest running real-world real-time CGM (rtCGM) study performed to date. In this study, the continuous use of rtCGM had a sustained and durable benefit with regards to glycemic control over a 3-year time period, with rtCGM being superior to self-monitoring of blood glucose in reducing A1C, hypoglycemia, and glycemic variability in individuals with type 1 diabetes regardless of their insulin delivery method.

Observational COMISAIR Study in Patients With T1D Who Chose Insulin Delivery Method (MDI or Pump) and Monitoring Method (SMBG or CGM), Staying on Chosen Therapy for 3 Years

Six-Month Randomized, Multicenter Trial of Closed-Loop Control in Type 1 Diabetes

Source: The New England Journal of Medicine 

Key Takeaway: This 6 month randomized trial showed use of a closed-loop system using the t:slim X2 insulin pump with Control-IQ Technology, (Tandem Diabetes Care) and a continuous glucose monitor (Dexcom G6, Dexcom) was safe and effective compared to sensor-augmented pump therapy (SAP). Participants in the closed-loop group achieved 70% time in range overall which meets the International Consensus Guidelines for people with diabetes. The closed-loop group also achieved significant improvements in hyperglycemia, HbA1c, mean glucose, and hypoglycemia (< 70 mg/dL < 54 mg/dL) as compared with the SAP group. Glycemic benefits were seen in the first month of the trial and were sustained over the entire 6-month period. Over 90% of participants said they trusted the device and found Control-IQ technology easy to use.

*Full article available for a fee

Intermittently Scanned CGM: Novel Glucose-sensing Technology and Hypoglycaemia in Type 1 Diabetes: A Multicentre, Non-masked, Randomised Controlled Trial

Source: The Lancet

Key Takeaway: This study conducted in Europe with over 300 participants found novel flash glucose testing reduced the time adults with well controlled type 1 diabetes spent in hypoglycaemia. Future studies are needed to assess the effectiveness of this technology in patients with less well controlled diabetes and in younger age groups.

Flash Glucose-Sensing Technology as a Replacement for Blood Glucose Monitoring for the Management of Insulin-Treated Type 2 Diabetes: a Multicenter, Open-Label Randomized Controlled Trial

Source: Diabetes Therapy

Key Takeaway: Flash glucose-sensing technology use in type 2 diabetes with intensive insulin therapy results in no difference in HbA1c change and reduced hypoglycemia, thus offering a safe, effective replacement for SMBG.

Quality of Life and Glucose Control After 1 Year of Nationwide Reimbursement of Intermittently Scanned Continuous Glucose Monitoring in Adults Living with Type 1 Diabetes (FUTURE): A Prospective Observational Real-World Cohort Study

Source: Diabetes Care

Key Takeaway: Nationwide unrestricted reimbursement of isCGM in people with type 1 diabetes treated in specialist diabetes centers results in higher treatment satisfaction, less severe hypoglycemia, and less work absenteeism, while maintaining quality of life and HbA1c.

A1C From Baseline to 12 Months After Initiation of isCGM