People with type 1 diabetes need long-term insulin injections. However, needles may cause discomfort or provoke anxiety if the patient has needle phobia, factors that contribute to poor compliance with insulin, especially in younger patients. Use of needle-free technology has been proposed as a strategy to mitigate these problems. There have been few studies on the efficacy of needle-free syringes for patients with type 1 diabetes. To determine the efficacy of needle-free injection of insulin in its patient population, people with type 1 diabetes, we conduct a pilot study to assess glycemic control and injection experience of patients. For the comparator device, we used an insulin pen. The primary objective is to explore whether needle-free syringes are more beneficial to control blood glucose than insulin pens of type 1 diabetes, which the blood sugar fluctuates significantly. The secondary objective is to evaluate the experience and safety of insulin administration by the needle-free injection.

This is a single-center, prospective, 1:1 parallel-group, randomized controlled trial. The intervention will last for 12 weeks. The laboratory staff who tests the HbA1c level, the outcome assessor who collects the blood glucose data and injection experience include the measurement of perceived pain, skin condition at the injection site, and device preference in participants, and the statisticians will be blinded to the treatment allocation.

After informed consent is obtained, the participants can attend an initial study visit to determine eligibility for the trial. We propose to enroll 60 patients with type 1 diabetes (T1DM), participants are randomized into two groups, 30 in the needle-free jet injection group and 30 in the pen injection group. Sample size estimation is based on hypothesized changes in the primary outcome pre-prandial glucose in the morning. Participants are randomized using a computer-generated list.

In order to ensure high quality data, two staff are responsible for the input of original data into the database to check and confirm the accuracy. When the data entered by two people are inconsistent, the auxiliary staff decides which data to use.

Data analysis will be conducted under the intention-to-treat principle by including all the randomized patients in the data analysis. Missing data will be filled in with multiple imputation method. Any substantial difference in baseline characteristics will be adjusted with mixed-model regression analysis. Sensitivity analysis will be conducted by using per-protocol data by excluding those patients who drop out of the RCT.

Inclusion Criteria:

• Individuals diagnosed with Type 1 Diabetes according to the 1999 World Health Organization report
• Insulin dependence from disease onset
• Older than 12
• The patient's blood glucose is stable after the washout period (insulin dose is less than 30% compared with the last adjustment).

Exclusion Criteria:

• Recent unstable angina, myocardial infarction, or severe cardiac failure, blood pressure ≥180/100mm Hg, activities of hepatic transaminases >2.5 times the upper limit of normal and estimated glomerular filtration rate <30mL/min/1.73m2
• Being pregnant
• Serious mental problems
• Abuse of alcohol or narcotics
• Use of systemic glucocorticoids
• Have any other condition or disease that may hamper from compliance with the protocol or complication of the trial