Needle-free injection of basal insulin improves fasting glucose variability as assessed by continuous glucose monitoring in T2DM: a prospective randomized multicenter open-label crossover study

Background: Fasting glucose variability (FGV) extensively promotes the onset and development of diabetic complications. This study aimed to evaluate the FGV in type 2 diabetes mellitus (T2DM) patients administered basal insulin using a needle-free insulin injector (NFII). Research design and methods: This was a prospective randomized multicenter open-label crossover study. We randomly assigned 48 T2DM patients to receive basal insulin by NFII or conventional insulin pen (CIP) for 7-14 days and were then crossed over after washout. We conducted continuous glucose monitoring to investigate the FGV, our primary outcome was a composite parameter of the FGV with a fasting blood glucose target between 4.4 and 6.1 mmol/L. Results: The coefficient of variation for sensor glucose at 6 a.m. with CIP was 11.67 (8.70,14.81)% vs. 9.48 (6.48,12.24)% with NFII (p = 0.003), and the coefficient of variation for mean sensor glucose at 5-6 a.m. with CIP was 12.70 (9.17,16.56)% vs. 9.23 (7.01,11.98)% with NFII (p < 0.001). The overall basal insulin dosage with CIP injection was 18.00 (16.00, 20.00) IU vs. 16.00 (12.00, 19.00) IU during NFII (p < 0.003). Conclusion: Compared with CIP, the use of the NFII to inject basal insulin improved FGV in T2DM.