Continuous glucose monitors (CGMs) are valuable tools for improving glycemic control, yet their accuracy might be influenced by physical activity. This study sought to assess the accuracy of the three latest factory-calibrated CGM systems available in Europe at the time the study was conducted, both during aerobic exercise and in typical daily scenarios. The accuracy evaluation, based on metrics such as the median absolute relative difference (MARD) and point and rate error-grid analyses (PEGA and REGA), involved 13 adults with type 1 diabetes. Participants wore all sensors during a 1 h in-clinic exercise session followed by a subsequent 3-day home period, with blood glucose measurements serving as reference values in both contexts. During exercise, no statistically significant differences in MARD were observed (Dexcom G6: 12.6%, Guardian 4: 10.7%, and Freestyle Libre 2: 17.2%; p = 0.31), and similarly, no significant differences emerged in PEGA-zone-AB (100%, 100%, 96.8%; p = 0.37). Nevertheless, Freestyle Libre 2 showed comparatively diminished accuracy in estimating glucose trends during exercise (REGA-zone-AB: 100%, 93.0%, 73.3%; p = 0.0003). In the home environment, Freestyle Libre 2 exhibited a significantly higher MARD when compared to the other systems (10.2%, 11.9%, 16.7%, p = 0.02). Overall, Dexcom G6 and Guardian 4 demonstrated superior accuracy in both exercise and daily life scenarios compared to Freestyle Libre 2.

OBJECTIVE: People with type 1 diabetes (T1D) struggle to manage exercise because of hypoglycemia risk. RESEARCH DESIGN AND METHODS: This systematic review and meta-analysis evaluated low-dose glucagon's efficacy for preventing and treating exercise-induced hypoglycemia in T1D. Medline, Embase, and Cochrane CENTRAL were searched for randomized controlled trials and crossover studies until September 2024. The analysis included T1D adolescents and adults treated with low-dose glucagon versus nonglucagon treatments. Studies with glucagon-like peptides, noninsulin combinations, or uncontrolled exercise settings were excluded. Two authors extracted the data. The methodological quality was assessed with the Risk of Bias-2 tool and Grading of Recommendations Assessment, Development and Evaluations framework. Risk of Bias 2 informed a sensitivity analysis. The meta-analysis employed a random effects model to estimate the pooled treatment effects on hypoglycemia and time below range (TBR) (glucose <3.9 mmol/L), as well as secondary outcomes and adverse effects. RESULTS: Of 6,792 records, 12 studies involving 248 individuals (mean age: 36 ± 10.5 years) met inclusion criteria. The meta-analysis showed significant reductions in hypoglycemia risk (risk ratio 0.54; 95% CI 0.35, 0.84) and TBR (−3.91 percentage points; 95% CI −6.27, 1.54) with low-dose glucagon. Sensitivity analysis yielded a slightly more confident effect size for hypoglycemia and TBR. However, overall adverse events increased with low-dose glucagon (risk ratio 2.75; 95% CI 1.07, 7.08). The included studies were few and heterogeneous, which may have influenced the overall outcomes. CONCLUSIONS: Low-dose glucagon reduces exercise-induced hypoglycemia and TBR in T1D individuals. Future research should optimize glucagon dosage and timing for various exercise types and durations to confirm real-world effectiveness.