CGM use linked with modest HbA1c decreases in patients with type 2 diabetes
Real-time continuous glucose monitoring (CGM) increased the percent of time in range among patients with type 2 diabetes compared with self-monitoring, and both real-time and flash CGM lowered HbA1c levels, a meta-analysis found.
Continuous glucose monitoring in real time (rt-CGM) and flash CGM helped lower HbA1c levels in individuals with type 2 diabetes, results of a systematic review and meta-analysis show.
Researchers analyzed 14 randomized controlled trials, nine of rt-CGM and five of flash CGM, that assessed the effects of CGM on glucose control and clinical outcomes in adults with type 2 diabetes, including changes in HbA1c levels, time in range, time in hyperglycemia, or time in hypoglycemia. Findings were published in The Journal of Clinical Endocrinology & Metabolism on Nov. 21.
The review found that using any CGM led to a statistically significant reduction in HbA1c levels of about 0.32%, with improvements seen in studies of patients using and not using insulin. Each type of device was linked with similar HbA1c reductions (0.34% and 0.33% for rt-CGM and flash CGM, respectively). The quality of evidence supporting the findings was rated as moderate. In addition, a pooled analysis of four trials found rt-CGM was linked with a statistically significant increase in percent of time in range compared with blood glucose self-monitoring.
“Duration of the included [randomized controlled trials] was relatively short and few studies reported on important clinical outcomes, such as adverse events, emergency department use, or hospitalization,” the researchers noted. For rt-CGM trials, follow-up times ranged from 12 to 32 weeks with a median of 12 weeks. Follow-up times were similar in flash CGM studies, ranging from 10 to 52 weeks (median, 24 weeks). Longer-term studies are needed to determine if the short-term improvements observed lead to improvements in clinically important outcomes, the authors added.
Data limitations meant researchers were unable to carry out subgroup analyses on associations between insulin use, duration of diabetes, or baseline HbA1c level and outcomes with CGM. Findings may also not be generalizable as participants in randomized controlled trials may be different from real-world patients, the authors noted.
Overall, “our analyses demonstrated that initiation of CGM led to a modest but significant decline in HbA1c of 0.32% among individuals with [type 2 diabetes]. Despite analyzing studies that included patients on a broad variety of baseline treatment regimens, there was minimal heterogeneity of results, which strengthens our confidence in these results,” they concluded.