Use of automated insulin delivery (AID) in people with type 1 diabetes (T1D) has increased in recent years. We analyzed data from the T1D Exchange Registry - an online longitudinal study following adults and children with T1D - to describe characteristics of AID use and its association with self-reported HbA1c, occurrence of diabetic ketoacidosis (DKA) symptoms, and occurrence of severe hypoglycemia events (SHE) . Of 12,065 participants (69.5% female, 87.5% non-Hispanic White, mean age 37.9 yrs, mean T1D duration 19.9 yrs) , 26.4% reported using AID, 43.6% using insulin pump without AID, and 30.0% using multiple daily injections (MDI) . Private insurance was reported in 77.4% of AID users, 74.9% pump without AID, and 66.3% MDI. Among the 3,185 AID users, 50.6% used predictive low glucose suspend (PLGS) features, including Medtronic 640G and Tandem Basal-IQ; 49.4% used hybrid closed-loop (HCL) , including DIY looping, Medtronic Auto Mode, and Tandem Control-IQ. Average HbA1c was lower in AID users than those using MDI and pump without AID; Incidence of SHE was lower among HCL users compared with PLGS users and AID users compared with MDI users (Table 1) . These cross-sectional real-world data support findings of previous clinical studies showing significant improvements in HbA1c with AID use, with HCL use providing additional protection against SHE. Disclosure J.Liu: None. W.Wolf: None. K.Miller: Research Support; Dexcom, Inc., Tandem Diabetes Care, Inc. C.Kelly: None. K.S.M.Chapman: None. M.Peter: None. D.Finan: None. H.Nguyen: None. K.Laferriere: None. C.Leon: None.

Diabetes outcomes are affected by socioeconomic factors including health insurance. While some research has examined the impact of health insurance in people with type 1 diabetes (T1D) (e.g., disruptions in health insurance on health outcomes) , it is less clear whether health insurance type (e.g., private versus government-sponsored) shares a unique association with diabetes outcomes. Thus, we examined relationships between demographics, socioeconomic status, and health insurance type with HbA1c in adults in the T1D Exchange Registry - an online longitudinal study of people living with T1D. Participants (N = 7725) were 42.2 years old (SD = 14.6) on average and 75.4% reported their gender as female. Most participants (92.2%) reported their race as White and 5.1% identified as Hispanic. Many participants used insulin pumps (71.3%) and continuous glucose monitors (CGM, 83.0%) . Self-reported HbA1c was 7.3% (SD = 1.58) on average. Health insurance type was categorized into private (79.0%) , Medicaid (9.6%) , Medicare (9.5%) , or no health insurance (1.9%) . Health insurance type, demographic factors (i.e., age, gender, race, ethnicity) , socioeconomic factors (i.e., income, education level) , and diabetes technology use (i.e., insulin pump, CGM) were entered simultaneously into a linear regression with HbA1c as the outcome variable. Private insurance was used as the reference group. Statistical significance was set at p < .05. We found lower HbA1c was associated with identifying race as White (Β = -0.21) , having higher income (Β = -0.10) , having higher education (Β = -0.17) , using an insulin pump (Β = -0.46) and using CGM (Β = -0.72) . Higher HbA1c was associated with identifying as female (Β = 0.14) and having either Medicaid (Β = 0.23) or no health insurance (Β = 0.30) . These results suggest, above and beyond other socioeconomic and demographic factors, health insurance type may contribute to small but meaningful differences in HbA1c. Disclosure C.Kelly: None. H.Nguyen: None. J.Liu: None. K.S.M.Chapman: None. M.Peter: None. C.Leon: None. K.Laferriere: None. J.Ravelson: None. W.Wolf: None.