Minoritized individuals with type 1 diabetes (T1D) have approximately 2% higher average A1c levels and twice the rate of hospitalizations, complications, and mortality as their white counterparts. However, the efficacy trials establishing the benefits of hybrid closed loop (HCL) pump therapy in T1D have been in more socially advantaged and predominantly non-Hispanic white patients. Use of this technology by individuals with T1D from underserved communities remains very low.

The investigators plan to conduct a randomized effectiveness trial - with broader eligibility criteria (including markedly elevated A1c) and longer follow up than the previous HCL efficacy trials - to evaluate the benefits, safety risks and treatment complications of HCL use in underserved adults with T1D. A comprehensive mixed-methods approach will be implemented to capture information about the user experience.

Participants will be randomized (3:1 ratio) to one of three FDA-approved HCL systems or continuous glucose monitoring and multiple daily injection therapy. Subjects will be followed for 9 months to collect data on effectiveness (glucose % time-in-range 70-180 mg/dL and % time < 70 mg/dL), safety (diabetic ketoacidosis and severe hypoglycemia events) and patient experience using the systems (including benefits and burdens, the impact of life stressors on HCL use, and how the match between HCL system functionality and the individual's needs and expectations impacts on user experience).

Inclusion Criteria:

• Clinical diagnosis of T1D for at least 12 months, on MDI for at least 6 months;
• A1c ≥7.0% with no upper limit at screening (The investigator will consider the participant A1c level, compliance with current diabetes management, and prior acute diabetic complications. For this reason, there is no upper limit on A1c specified for eligibility);
• Able to understand, speak and read English (Given the language limitations in currently available pump interfaces, subjects who are not able to understand written English will not be eligible);
• Willingness to use either lispro or aspart insulin and no other insulin or new non-insulin diabetes pharmacotherapy during the study;
• Total daily dose of insulin of at least 10 units/day;
• Investigator believes that the participant will be able to successfully adhere to the study protocol.

Exclusion Criteria:

• Current use of insulin pump or closed loop insulin pump system;
• Unable to provide informed consent;
• Currently taking hydroxyurea or have medical condition that may necessitate use of hydroxyurea;
• Current use of SGLT-2 inhibitors or sulfonylureas (If using GLP-1RA, pramlintide or metformin, must be on a stable dose for 3 months prior to enrollment);
• Tape allergy or skin condition precluding use of pump or CGM;
• Females who are pregnant or intending to become pregnant (since automated algorithm adaption for some of the HCL systems used in the trial cannot be configured to adjust to changing insulin demands of pregnancy);
• Current renal dialysis or plan to begin renal dialysis during study. Most recent eGFR <30 ml/min is exclusionary (within last 2 years is acceptable);
• Active cancer treatment;
• Extreme visual or hearing impairment that would impair ability to use CGM and pump;
• Cognitive concerns;
• Significant psychiatric diagnosis or substance abuse disorder that in the investigator's opinion impairs ability of the individual to participate.