Background: American Diabetes Association (ADA) recommends psychosocial assessment for people with diabetes, including diabetes-related distress. Elevated diabetes-related distress is associated with poor self-management, lower medication adherence, and poorer quality of life. Insulin delivery methods are multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII). Because people with type 1 diabetes mellitus (T1DM) require comprehensive insulin therapy to manage blood glucose, we explored the association of insulin delivery methods and diabetes distress in this group. Methods: The U.S. Air Force Diabetes Center of Excellence (DCOE), a specialty clinic for adults who are Military Health System beneficiaries, administers the validated 17-item Diabetes-related Distress Scale (DDS-17) as part of standard care. Patient data were analyzed from June 2015 to August 2016 using SPSS version 22. Patients were free to choose the method of insulin delivery with minimal or no additional cost. Results: There were 203 patients with T1DM who completed the DDS-17 as part of standard care during the time period. Patients were categorized as CSII (57.6%) or MDI (42.4%). Women were significantly more likely to choose MDI over CSII than men (P = 0.003). DDS-17 scores were low in both groups, and there were no significant differences in DDS-17 by insulin delivery method. Furthermore, no significant differences were found in hemoglobin A1c (HbA1c) between CSII (7.9% or 63 mmol/mol) and MDI (8.1% or 65 mmol/mol) users (P = 0.22) and no significant differences in body mass index (BMI) between patients using CSII (M = 28.33 kg/m2) and MDI (28.49 kg/m2) users (P = 0.15). Conclusions: Our study demonstrated that if patients are relatively free to choose the insulin delivery method (minimal or no financial constraints), there were no differences in diabetes distress scores, HbA1c, or BMI between CSII and MDI. Therefore, people with T1DM may benefit from choosing the method of insulin delivery that will enable them to achieve individual goals and manage diabetes-related distress
