Continuous Glucose Monitoring and Hypoglycaemia Metrics With Once-Weekly Basal Insulin Fc Versus Insulin Degludec: A Systematic Review and Meta-Analysis

Introduction

Once-weekly basal insulin Fc (BIF) offers a promising alternative to daily basal insulin by reducing injection burden while maintaining glycaemic control. However, comprehensive comparisons with insulin degludec regarding continuous glucose monitoring (CGM) metrics and hypoglycaemia outcomes remain limited. This meta-analysis evaluates these critical parameters.

Methods

We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) comparing once-weekly BIF with once-daily insulin degludec in type 1 and type 2 diabetes. Outcomes included CGM-derived glycaemic variability, time in range, time above/below range and hypoglycaemia event rates. Data were pooled using random-effects models, with heterogeneity assessed via I² statistics.

Results

Five RCTs (n = 2427) were included. BIF demonstrated comparable glycaemic variability (within-day CV: MD = 0.06, p = 0.90; between-day CV: MD = -0.26, p = 0.30) and Time in range (MD = 0.56, p = 0.27) versus degludec. However, BIF increased time spent in the mild hypoglycaemia range (54–69 mg/dL) (MD = 0.30, p = 0.0004) and clinically significant hypoglycaemia event rates (rate ratio = 1.20, p < 0.00001). Severe hypoglycaemia event rates were higher with BIF (rate ratio = 3.34, p < 0.0001). Nocturnal hypoglycaemia and time above range (> 250 mg/dL) did not differ significantly.

Conclusion

Once-weekly BIF provides similar overall glycaemic control to insulin degludec but with increased time in mild hypoglycaemia and higher event rates of clinically significant and severe hypoglycaemia. These findings highlight the need for individualised dosing and monitoring when transitioning to weekly insulin regimens.