Insulin Injection Technique is Associated with Glycemic Variability in Patients with Type 2 Diabetes

INTRODUCTION: Patients with type 2 diabetes (T2D) receiving premixed insulin often fail to achieve optimal glycemic control. The insulin injection technique (IT) itself may be one of the factors affecting glycemic variability (GV). The aim of this study was to assess the relationship between GV and IT in patients with T2D using premixed insulin. METHODS: This was a single center, cross-sectional, and self-controlled trial. Patients with T2D using premixed insulin were enrolled as inpatients. The 4-day study consisted of a 2-day patient insulin injection period (days 0 and 1) and a 2-day specialist nurse insulin injection period (days 2 and 3). Patient insulin IT were assessed on day 1 by two independent nurses using a skill-related scale consisting of 15 items, with a maximum score for each item of 2 and a total optimum score of 30. All patients underwent 96-h continuous glucose monitoring (CGM) during the 4-day study, and CGM data collected on days 1 and 3 were recorded and analyzed. The primary outcome was the relationship between the insulin IT score and the 24-h mean amplitude glycemic excursion (MAGE) during the patient injection period. RESULTS: A total of 52 inpatients with T2D who used premixed insulin were recruited and completed the study. The mean total insulin IT score of these patients was considerably lower than the optimum score (17.0 ± 4.4 vs. 30). Our CGM data showed that the MAGE was significantly higher during the patient injection period than during the nurse injection period (P < 0.05). Multiple linear stepwise regression analysis showed that the patient IT score was negatively correlated to the MAGE (P < 0.05). The patient IT score was also negatively correlated to glycated hemoglobin (HbA(1c); P < 0.05). CONCLUSIONS: A poorer insulin IT may negatively affect GV and HbA(1c) control in patients with T2D using premixed insulin. Our data indicate that the insulin IT is important for short- and long-term glycemic control. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identification number: NCT03513055.