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. Clinical trial registration: https://www.chictr.org.cnIdentifier is ChiCTR2000034674.