[A comparative study of the effects of needle free (INJEX30) versus insulin pen injection on insulin absorption in diabetic patients].

Objective: To evaluate the effect of the needle free injection system (INJEX30) and insulin pen on insulin absorption and glycemic control in diabetic patients.

Methods: A total of 30 diabetic patients on insulin therapy without obvious complications were enrolled in the study with average BMI of 25.24 kg/m(2). A comparison study was carried out in those subjects with the INJEX30 and insulin pen at 1(st) day and 5(th) day. After an overnight fasting of 8-10 h, a standard mixed meal (50 g bread, 50 g egg and 250 ml milk) was given to each patient. Blood samples at 0, 20, 40, 60 min of the standard mixed meal were collected to test plasma glucose, serum insulin and C peptide.

Results: No difference was shown in fasting plasma glucose, serum insulin and C peptide between the patients with the two injection methods. The area under the curve (AUC) of plasma glucose and serum C peptide was significantly lower after the INJEX30 injection than that after insulin pen injection [plasma glucose AUC (542 ± 172)min·mmol·L(-1) vs (601 ± 199) min·mmol·L(-1), P < 0.01; C peptide AUC (70 ± 53) min·µg· L(-1) vs (80 ± 58) min·µg·L(-1), P < 0.01]. The AUC of serum insulin was significantly higher after the INJEX30 injection than that after insulin pen injection [serum insulin AUC (5621 ± 3790) min·mIU·L(-1) vs (4285 ± 3376) min·mIU· L(-1), P < 0.01]. No difference was found in the AUC of serum insulin between the two injection methods in the patients with BMI below 25.24 kg/m(2), while the AUC of serum insulin was significantly higher after the INJEX30 injection than the insulin pen injection in the patients with BMI above 25.24 kg/m(2) [serum insulin AUC (6453 ± 4099) min·mIU· L(-1) vs (4879 ± 3701) min·mIU·L(-1), P < 0.01].

Conclusion: The INJEX30 improves the serum insulin level which may lead to a beneficial effect on the glycemic control. Such effect is more obvious in the overweight patients.