Prescribed Total Daily Insulin Dose and Predictors of Insulin Dose for Adults with Type 2 Diabetes on Multiple Daily Injections of Insulin: A Retrospective Cohort Study

Background/Objectives: Limited evidence is available regarding insulin total daily dose (TDD), or the factors associated with TDD, among adults with type 2 diabetes (T2D) using multiple daily injections of insulin (MDI). Our aim was to determine the percentage of adults in the United States (US) with T2D who are prescribed MDI, their prescribed insulin TDD, and potential factors associated with TDD. Methods: This retrospective cohort study used deidentified data from the US IQVIA ambulatory electronic medical record database to study adults (≥18 years) with T2D initiating MDI (≥3 daily basal-plus-prandial insulin injections) from 1 January 2017 to 1 July 2022. The TDD was calculated from first evidence of MDI (index date). We used a generalized linear model regression analysis to model the relationship between TDD and clinically relevant factors associated with TDD. Results: During the study period, of 3,339,663 adults with T2D, 451,769 (13.5%) had ≥1 basal insulin prescriptions, 206,000 (6.2%) had both basal and prandial insulin prescriptions, and 41,215 (1.2%) were prescribed MDI (mean age, 58 years; 52% women; 62% White/Caucasian, 14% African American; mean body mass index [BMI], 34 kg/m2). Mean TDD was 96 units (1.0 units/kg/day); median TDD was 80 units (interquartile range, 54–124). In the regression analysis (model R2, 0.14), factors predicting lower TDD included female sex, African American race, and prior 6-month (pre-index) prescriptions of sulfonylurea, metformin, or 2–3 noninsulin glucose-lowering medications. Predictors of greater TDD included increasing BMI, age 30–64 years, and pre-index SGLT2 inhibitor or GLP-1 RA prescription. Conclusions: Among US adults with T2D, 1.2% were prescribed MDI, with a wide range of TDD and median TDD of 80 units. Further research in other populations and using other data sources is warranted to explore prescribed insulin TDD for T2D and to examine other potentially relevant predictors of TDD.