Purpose:Substance use and sexual activity can impact the glycemic management and health of people living with type 1 diabetes (T1D), but data in pediatric populations are sparse. We set out to explore patient engagement and knowledge of the impacts on glycemia from substance use and sexual activity in a pediatric type 1 diabetes center. Patients and methods:Surveys assessing rates and frequency of cannabis use, alcohol use, sexual activity, and participants' knowledge of their glycemic impacts were administered to participants ≥18 years old with type 1 diabetes between July 2024 and May 2025 at the Barbara Davis Center for Diabetes pediatric clinic. Respondents were classified by substance use (alcohol and/or cannabis) and sexual activity. Demographic and glycemic data were obtained from electronic medical records. Student's t-tests and chi-square tests were performed to compare between groups. Linear regression models were fit to compare HbA1c by cannabis use, adjusting for age, diabetes duration, non-Hispanic White race and ethnicity, and automated insulin delivery use. Results:Of the 103 participants, 50 (48.5%) and 56 (54.4%) reported cannabis and alcohol use, respectively. Sexual activity was reported by 63 (61.2%) individuals. Cannabis users had a 0.8% higher HbA1c compared to non-users, even when controlling for confounders, and were less knowledgeable about its impact on glucose levels. Alcohol users were more knowledgeable about alcohol's impacts compared to non-users, especially concerning delayed hypoglycemia. Knowledge of goal HbA1c during pregnancy was low. Conclusion:Substance use and sexual activity are common among emerging adults with T1D, though their knowledge around the impact on diabetes is limited. Consistent and comprehensive education on these topics should begin early as part of routine diabetes care in pediatric populations. Further research into the effect of cannabis on glucose levels and diabetes care is necessary.

INTRODUCTION:Sleep health is critical for physical and mental well-being, yet adolescents with type 1 diabetes (T1D) often experience sleep disruptions due to nocturnal glucose management, fear of hypoglycemia, and device alarms. Despite evidence linking poor sleep to adverse diabetes outcomes, sleep assessment is rarely integrated into routine care. METHODS:This mixed-methods observational study evaluated sleep patterns and barriers to sleep in adolescents with T1D (ages 11-17 years) recruited from a pediatric diabetes clinic. Participants completed 7 days of actigraphy and sleep diaries, surveys assessing sleep and psychosocial factors, and diabetes device downloads. A subset completed qualitative interviews exploring sleep experiences and perceived facilitators and barriers. Quantitative analyses examined sleep duration, efficiency, and glycemic metrics; qualitative data were coded for themes. RESULTS:Among 70 participants, 54% did not meet American Academy of Sleep Medicine recommendations for sleep duration. The mean actigraphic sleep duration was 7.1 ± 0.9 h, with older adolescents sleeping less than younger peers (p = 0.002). Lower sleep efficiency was observed in those not achieving sufficient sleep (p = 0.011). No significant differences in glycemic outcomes were found by sleep sufficiency. Qualitative interviews (n = 31) revealed school and extracurricular demands as the most common barriers, with diabetes-related factors (e.g., nocturnal alarms) contributing to awakenings. Most adolescents reported good perceived sleep quality but expressed interest in receiving recommendations to improve sleep health. CONCLUSIONS:Over half of adolescents with T1D fail to achieve recommended sleep duration, and qualitative findings highlight modifiable behavioral and diabetes-related barriers. Routine sleep screening and tailored interventions should be developed in efforts to address overall health in adolescents with T1D.

BACKGROUND:Continuous glucose monitoring (CGM) improves glycemic outcomes but inpatient use in the United States is not FDA approved, despite the potential need for frequent glycemic monitoring during hospitalization. We sought to assess CGM accuracy in the pediatric hospital setting and to evaluate the impact of potential modifiers of accuracy, including sensor wear day, hospitalization day, and glucose changes. METHODS:In this retrospective cross-sectional accuracy study among youth and young adults with diabetes hospitalized at two pediatric centers, reference point-of-care (POC) capillary glucose values were compared with Dexcom G7 CGM glucose readings (paired within 5 min). Accuracy was assessed using standard metrics, including mean absolute relative difference (MARD) and Parkes error grids, overall, and stratified by sensor wear day, hospital day, and CGM glucose rate of change. RESULTS:We analyzed 544 POC-CGM glucose pairs from 68 participants with diabetes aged 2-22 years (mean 12.4 ± 5.8 years old, 58.8% female, 66.2% White, 8.8% Hispanic) during 80 hospital encounters. The overall MARD was 12.5%. Accuracy was comparable on sensor wear day 1 and days 2-6 (MARD 12.3% vs 13.6%, respectively) and was best on wear days 7-10 (MARD 10.6%). Accuracy improved from hospital day 1 (MARD 13.7%) to hospital days 2-4 and 5-30 (MARD 10.4% and 12.5%, respectively). Overall and on wear day 1, almost all glucose pairs (99%) fell within low-risk Parkes error grid zones A and B. Accuracy was best with a flat [-1 to 1 mg/(dL·min)] rate of change (MARD 11.5%-11.9%) and was reduced with rapidly rising or falling [beyond -2 or 2 mg/(dL·min)] CGM values (MARD 16.6%-18.4%). CONCLUSIONS:In this pediatric hospital CGM accuracy study, MARD was within a favorable range of <14% overall and throughout sensor wear and hospitalization. Reduced accuracy with rapidly changing glucose highlights the need to incorporate trend arrows into hospital CGM protocols.

Objective: Automated Insulin Delivery (AID) requiring manual pre-mealtime boluses are the standard of care for people with type 1 Diabetes (PWD). We evaluated the safety and feasibility of the Automated Insulin Delivery as an Adaptive NETwork (AIDANET) system used without meal announcements in both supervised and home settings across a diverse population of PWD. Research design and methods: Adults (>25 y), young adults (18-25 y), and adolescents (14-18 y) were enrolled at three sites in the United States to compare the AIDANET system used in fully closed-loop (FCL) to usual care in a randomized crossover study. Participants spent ~5 days using FCL in a supervised environment followed by ~7 days of use at home. The prespecified primary outcome was defined as the change in mean sensor glucose (MSG) between the second week of UC and the week of FCL at-home period. Results: Overall, 34 participants: 12 adults, 10 young adults, 12 adolescents (25.4±12.6 years, 62% female, HbA1c 8.0±1.1%, 94% Hybrid Closed Loop (HCL) users during UC) completed the study. MSG improved from 178mg/dL to 164mg/dL, UC vs. FCL; p = 0.0058). The percentages of time in range (70-180mg/dL), time in tight range (70-140 mg/dL), and time above ranges (>180mg/dL, and >250mg/dL) also significantly improved, primarily overnight. The percentage of time below ranges 70 and 54 mg/dL were significantly non-inferior in FCL compared to UC. Conclusions: FCL therapy with the AIDANET system can significantly improve average glycemic control while removing the need for mealtime bolusing for a broad population of PWD.

Introduction and Objective: Diabetes device use in T1D is associated with improved clinical outcomes. However, many people experience device-related skin reactions. Our aim was to assess psychosocial outcomes between YYA with T1D that experience device-related skin reactions and those that do not. Methods: YYA (2-25 years) with T1D that use diabetes devices completed an in-house developed survey, and the Problem Area in Diabetes (PAID, measure of diabetes distress, higher scores indicate more distress) and diabetes-specific Pediatric Quality of Life (PedsQL, higher scores indicating better well-being) surveys. Participants were dichotomized based on experiencing skin reactions to devices. T-tests were performed on HbA1c and PAID/PedsQL outcomes. Results: Eighty-eight YYA participated (15.4±6.2 yrs, T1Ddur 6.8±5.4 yrs, HbA1c 7.0±1.0%, 59.1% Female, 88.0% NHW, 98.9% CGM users, 90.9% pump users). Those with device-related skin reactions had significantly higher PAID scores and frequent self-reported negative feelings. No other significant differences were found. Conclusion: Youth and young adults with device-related skin reactions experience diabetes distress and device-related negative feelings, which can impact device use and overall well-being. Future research should focus on mitigating skin reactions and assessing the impact on psychosocial well-being. A.J. Karami: None. V.S. Fadhel Hernández: None. C. Sakamoto: None. K. Taylor: None. E. Fivekiller: None. C. Berget: Consultant; Insulet Corporation. Advisory Panel; Tandem Diabetes Care, Inc. Other Relationship; Tandem Diabetes Care, Inc, Insulet Corporation, embecta. S. Lange: Advisory Panel; Medtronic. E.C. Cobry: Advisory Panel; Dexcom, Inc. National Institute of Diabetes and Digestive and Kidney Diseases (2T32DK063687)

Objective: To evaluate the function and safety of the SteadiSet™ infusion set over a continuous 7-day wear period in adults with type 1 diabetes. Research Design and Methods: Participants used a SteadiSet infusion set with a t:slim X2™ insulin pump with Control-IQ™ technology, and either insulin aspart or insulin lispro, for a target of 7 days for 12 consecutive wear periods. Each set removed before 7 days was adjudicated by an independent committee to assess the cause of early removal and to determine whether criteria for primary or key secondary endpoints were met. Results: There were 260 participants who inserted 3028 infusion sets. For the primary endpoint, the Kaplan-Meier 7-day survival estimate was 95% (95% CI 94% to 96%). For the key secondary endpoint, which expanded the reasons for a failed infusion set, the Kaplan-Meier 7-day survival estimate was 84% (95% CI 82% to 86%). For both endpoints, the P value was <0.001 compared with a prespecified survival rate of 75%. Time-in-range 70-180 mg/dL (TIR) increased through day 3 of set wear and then decreased through day 7, with the average TIR being 70.6% over the entire wear period across all infusion sets, including those that failed. An increase in total daily insulin was observed from day 4 through day 7. Conclusions: The 7-day survival of the SteadiSet infusion set was very high for the primary endpoint and at an acceptable level with respect to early removal for any reason related to the device.

Monogenic diabetes is a group of diseases that encompasses a growing number of genetic abnormalities affecting pancreatic function/development leading to glycemic dysregulation. This includes conditions that have historically been referred to as maturity onset diabetes of the young or MODY in addition to neonatal diabetes mellitus. While recognition of a genetic or inherited form of diabetes has been known for decades, advances in molecular genetic testing have resulted in identification of specific forms of monogenic diabetes. Despite this, these genetic forms of diabetes remain widely underreported. It is important to be able to identify genetic forms of diabetes as treatment, monitoring for microvascular and macrovascular complications, and overall management varies for the different forms of monogenic diabetes. Furthermore, the identification of a specific monogenic form of diabetes can significantly impact the person's quality of life and other family members, as well as health care costs. This article highlights the identification, treatment, and management for various forms of monogenic diabetes and addresses some unmet needs in caring for people with monogenic forms of diabetes.

OBJECTIVE:Sleep is critically important to children's well-being, and inadequate sleep duration significantly increases the risk for poor health outcomes. Insufficient sleep is a common finding in the pediatric population, specifically among individuals with type 1 diabetes. The aim of this study is to determine whether there are differences in sleep and glycemic outcomes between the summer and the school year among school-aged children with type 1 diabetes. RESEARCH DESIGN AND METHODS:School-aged children with type 1 diabetes enrolled in a hybrid closed-loop (HCL) automated insulin delivery (AID) and sleep study wore actigraphy watches and completed sleep diaries and surveys to assess their sleep quality and duration. Glycemic outcomes and sleep data were analyzed to determine variability between the summer and school year. RESULTS:On average, children (6-17 years of age) with type 1 diabetes using an HCL AID system slept more during the school year than in the summer, although this difference did not achieve statistical significance (442.2 vs. 483.3 minutes, P = 0.053). There was also no statistically significant difference in glycemic control between summer and the school year. CONCLUSION:School-aged children with type 1 diabetes using a hybrid closed-loop AID system did not experience statistically significant differences in sleep or glycemic outcomes between summer and the school year. Use of a hybrid closed-loop AID system may play a role in eliminating variations in sleep and glycemic outcomes between summer and the school year. Sleep is a crucial factor in the management of type 1 diabetes, and further research is needed to identify interventions to improve sleep among school-aged children.

Introduction and Objective: Most adolescents do not achieve sleep recommendations and T1D causes unique nocturnal disruptions which may contribute to poor sleep. Yet, screening for sleep health is not regularly part of diabetes visits. The purpose of this study was to evaluate the feasibility of sleep screening in adolescents with T1D. Methods: Adolescents (11-17yo) with T1D completed sleep screening consisting of PROMIS Sleep Disturbance (SD) and Sleep-Related Impairment (SRI) surveys (4-items each, t-scores >50 indicate more problems than the population mean). For this study, a score of >55 was considered clinically significant, indicating need for further assessment. Participants were categorized by gender and age (11-13yo and 14-17yo). Results: 50 adolescents (age 14.7±2.2yrs, T1D duration 6.4±4.5yrs, 50% Female, 66% NHW) participated. PROMIS SD and SRI mean (SE) t-scores were 55.1 (3.2) and 53.6 (3.1), respectively, and took 5.5 minutes to complete. 31 (62%) scored above 55 on at least one survey. Females had significantly higher t-scores for both SD and SRI (Table). There were no differences by age. Conclusion: PROMIS sleep surveys identified a high proportion of adolescents with T1D with sleep concerns. Females reported higher levels. Routine screening for sleep health in adolescents using the PROMIS SD and SRI surveys is feasible during routine diabetes visits and can be an important part of T1D care. E.C. Cobry: Advisory Panel; Dexcom, Inc. E. Fivekiller: None. S.S. Jaser: None. L.J. Meltzer: Consultant; Harmony Biosciences, Egetis Therapeutics, Zepp Health. R. Wadwa: Consultant; Dexcom, Inc., Tandem Diabetes Care, Inc. Advisory Panel; Provention Bio, Inc, Provention Bio, Inc, Microbion, Microbion, Sequel Med Tech. Research Support; Dexcom, Inc., Eli Lilly and Company, Tandem Diabetes Care, Inc. Breakthrough T1D (5-ECR-2022-1179-A-N)

Introduction and Objective: HCL is the preferred insulin delivery method for people with T1D, however mealtime carbohydrate counting limits benefit. Use of AI to implement automated insulin delivery (AID) algorithms, able to avoid mealtime interactions, could alleviate burden and broaden use. We tested the latest UVA AID neural network-based system (AIDANET) in FCL in a people with T1D. Methods: Adults (>25 y, n=12), young adults (18-25 y, n=10), and adolescents (14-17 y, n=12) were enrolled at three sites to compare AIDANET in FCL to usual care in HCL (NCT06041917). Participants spent 5 days using FCL in a supervised hotel environment followed by 7 days of at-home use. Usual care data was collected randomly for two weeks before or after FCL use. The prespecified primary outcome was difference in mean CGM. Results: Overall, 34 participants (25.4±12.6 y, 62% F, HbA1c 8.0±1.1%) completed the study. Mean CGM significantly improved from 177.9 mg/dL with HCL to 163.8 mg/dL with FCL (-14.1 mg/dL; p=0.013; Table). TIR, TITR, TAR>180, and TAR>250 also significantly improved. TBR<70 and TBR<54 were non-inferior in FCL vs HCL. CV increased in FCL vs HCL but SD did not. Daily meal boluses decreased from 4.0±2.6 to 0.0±0.0 (p<0.001). Conclusion: Fully closed loop therapy with the AIDANET system can significantly improve average glycemia while removing the need for mealtime bolusing for people with T1D. G.P. Forlenza: Advisory Panel; Medtronic. Research Support; Medtronic, Dexcom, Inc. Consultant; Dexcom, Inc. Research Support; Insulet Corporation. Consultant; Insulet Corporation. Research Support; Tandem Diabetes Care, Inc. Advisory Panel; Tandem Diabetes Care, Inc. Research Support; Abbott. Advisory Panel; Sequel Med Tech. M. Moscoso-Vasquez: Other Relationship; Dexcom, Inc. Research Support; Tandem Diabetes Care, Inc, National Institute of Diabetes and Digestive and Kidney Diseases. S.A. Brown: Research Support; Dexcom, Inc., Insulet Corporation, Tandem Diabetes Care, Inc, Tolerion, Roche Diabetes Care. Other Relationship; MannKind Corporation. G. Capodanno: None. E. Cengiz: Advisory Panel; Novo Nordisk, Arecor Therapeutics, Eli Lilly and Company, Tandem Diabetes Care, Inc, Portal Insulin, MannKind Corporation. E.C. Cobry: Advisory Panel; Dexcom, Inc. M.D. DeBoer: Research Support; Dexcom, Inc., Tandem Diabetes Care, Inc, Medtronic. R. Wadwa: Consultant; Dexcom, Inc., Tandem Diabetes Care, Inc. Advisory Panel; Provention Bio, Inc, Provention Bio, Inc, Microbion, Microbion, Sequel Med Tech. Research Support; Dexcom, Inc., Eli Lilly and Company, Tandem Diabetes Care, Inc. J.C. Wong: Research Support; Abbott, Dexcom, Inc., Tandem Diabetes Care, Inc. L. Ekhlaspour: Other Relationship; Medtronic. Advisory Panel; Abbott, Medtronic. Consultant; Jaeb Center for Health Research. Research Support; MannKind Corporation. Speaker's Bureau; Insulet Corporation. Advisory Panel; Sequel Med Tech. Other Relationship; Tandem Diabetes Care, Inc. Research Support; Abbott. Other Relationship; Sanofi. M.D. Breton: Speaker's Bureau; Sinocare Inc, Tandem Diabetes Care, Inc. Consultant; Roche Diabetes Care, Boydsense. Breakthrough T1D (2-SRA-2023-1275-M-B)

Introduction and Objective: The AIDANET system uses an adaptive algorithm that removes the need for meal announcement. This may help address age-specific obstacles in T1D, as older people may struggle with diabetes technology, while younger people face hormonal changes and inconsistencies in premeal dosing. Given these challenges, the glycemic outcomes of the AIDANET system in FCL were evaluated across three age groups. Methods: This study was a randomized, crossover trial evaluating the safety and feasibility of the AIDANET system. Sensor glucose data was collected from: Adolescents (14-17 y), Young Adults (18-25 y), and Adults (26-60 y). Participants used the system in FCL during a supervised hotel setting for 5 days followed by a 7-day home period. Each cohort underwent a 14-day usual care (UC) period. Results: The Adult cohort had a significant increase in TIR and TITR by 8.0% and 9.0%, respectively (Table). TAR180 also significantly decreased by 8.1%. Young Adults exhibited non-inferior results for TBR54 between UC and FCL. For Adolescents, TIR, TITR, TAR180, TAR250, and TBR54 values were non-inferior between UC and FCL. Conclusion: Adults significantly improved their glycemic outcomes with short-term use of the FCL system. Future research with long-term wear may be needed to give the system more time to adapt to the unique needs of all age groups. J.Y. Hosseinipour: None. G.P. Forlenza: Advisory Panel; Medtronic. Research Support; Medtronic, Dexcom, Inc. Consultant; Dexcom, Inc. Research Support; Insulet Corporation. Consultant; Insulet Corporation. Research Support; Tandem Diabetes Care, Inc. Advisory Panel; Tandem Diabetes Care, Inc. Research Support; Abbott. Advisory Panel; Sequel Med Tech. L. Ekhlaspour: Other Relationship; Medtronic. Advisory Panel; Abbott, Medtronic. Consultant; Jaeb Center for Health Research. Research Support; MannKind Corporation. Speaker's Bureau; Insulet Corporation. Advisory Panel; Sequel Med Tech. Other Relationship; Tandem Diabetes Care, Inc. Research Support; Abbott. Other Relationship; Sanofi. J.C. Wong: Research Support; Abbott, Dexcom, Inc., Tandem Diabetes Care, Inc. E. Escobar: None. E.C. Cobry: Advisory Panel; Dexcom, Inc. M. Moscoso-Vasquez: Other Relationship; Dexcom, Inc. Research Support; Tandem Diabetes Care, Inc, National Institute of Diabetes and Digestive and Kidney Diseases. S.A. Brown: Research Support; Dexcom, Inc., Insulet Corporation, Tandem Diabetes Care, Inc, Tolerion, Roche Diabetes Care. Other Relationship; MannKind Corporation.

Introduction and Objective: HCL has become standard therapy for T1D, with particular glycemic improvements overnight. These systems require meal announcement for optimal daytime glycemia. FCL therapy will reduce daytime diabetes management burden and may further improve nighttime glycemia. Methods: Adolescents (14-17yrs), young adults (18-25yrs), and adults (26-60yrs) were enrolled at 3 sites to evaluate a novel FCL system (Automated Insulin Delivery as an Adaptive NETwork [AIDANET]). AIDENET was initiated in a supervised hotel setting, followed by 7 days at home. Results were analyzed by time of day (nighttime: 12am-6am) and compared to usual care with HCL. T-tests were used to assess non-inferiority and difference of glycemic metrics with a primary outcome of mean sensor glucose. Results: 34 subjects (25.4±12.6 yrs, HbA1c 8.0±1.1%, 62% F) participated. Daytime FCL use was non-inferior, but not different, to HCL for all glycemic metrics except coefficient of variation (Table). Nighttime FCL wear was both non-inferior and significantly different (p<0.05) for most glycemic metrics. Conclusion: The AIDANET FCL system significantly improved nighttime glycemia and was equivalent during the daytime compared to HCL. Longer use studies are necessary to determine sustainability in the home setting. E.C. Cobry: Advisory Panel; Dexcom, Inc. M. Moscoso-Vasquez: Other Relationship; Dexcom, Inc. Research Support; Tandem Diabetes Care, Inc, National Institute of Diabetes and Digestive and Kidney Diseases. L. Towers: None. J.C. Wong: Research Support; Abbott, Dexcom, Inc., Tandem Diabetes Care, Inc. S.A. Brown: Research Support; Dexcom, Inc., Insulet Corporation, Tandem Diabetes Care, Inc, Tolerion, Roche Diabetes Care. Other Relationship; MannKind Corporation. L. Ekhlaspour: Other Relationship; Medtronic. Advisory Panel; Abbott, Medtronic. Consultant; Jaeb Center for Health Research. Research Support; MannKind Corporation. Speaker's Bureau; Insulet Corporation. Advisory Panel; Sequel Med Tech. Other Relationship; Tandem Diabetes Care, Inc. Research Support; Abbott. Other Relationship; Sanofi. Breakthrough T1D (2-SRA-2023-1275-M-B)

Introduction and Objective: Use of insulin pumps and continuous glucose monitors (CGM) can cause dermatological complications which may vary by gender and race. We sought to assess the prevalence of skin reactions among different genders and races. Methods: Youth and young adults (2-25 years) with T1D wearing a diabetes device were invited to complete a survey assessing the presence of device-related skin reactions. Participants were classified based on gender (female, male, other) and self-reported race as non-Hispanic white (NHW) or nonwhite. Results: 88 participants enrolled (mean age 15.4 ± 6.2yrs, 59.1% female, mean HbA1c 7.0±1.0%). 88% identified as NHW. There were no significant differences in the presence of skin reactions between gender (p = 1) or race (p = 0.085). Conclusion: Device-related skin reactions are common but do not differ between gender or race. Greater representation from non-white participants is underway to fully evaluate the prevalence of device-related skin reactions. Disclosure V.S. Fadhel Hernández: None. A.J. Karami: None. C. Sakamoto: None. K. Taylor: None. E. Fivekiller: None. C. Berget: Consultant; Insulet Corporation. Advisory Panel; Tandem Diabetes Care, Inc. Other Relationship; Tandem Diabetes Care, Inc, Insulet Corporation, embecta. S. Lange: Advisory Panel; Medtronic. E.C. Cobry: Advisory Panel; Dexcom, Inc. Funding NIDDK (2T32DK063687)

Introduction and Objective: Patient acceptance of an FCL automated insulin delivery (AID) system has not been previously studied. Methods: Adolescence (14-17yo), young adults (18-25yo), and adults (25-60yo) with type 1 diabetes enrolled in a randomized crossover device safety and feasibility study of the AIDANET system. Users participated in a 5-day supervised hotel stay, followed by 7 days at home. At baseline and after home use, users completed the INSPIRE survey, a measure of expectations of AID, and the Technology Acceptance Scale (TAS), which measures experiences with technology and the benefits and burdens. Paired t-tests were conducted for the whole cohort, each of the three age groups, and low HbA1c (<8.0%) and high HbA1c (8.0-12.0%) subgroups. Results: For the 33 participants (25.5±12.8yrs; 63%F), INSPIRE scores significantly decreased after 11 days of use (p=0.001). Young adults, adolescents, and low HbA1c groups showed significant decreases in INSPIRE scores (p=0.042, 0.006, 0.005, respectively). There was no significant change for adults and high HbA1c groups. TAS scores significantly decreased in adolescences (p=0.028), but remained unchanged in all other subgroups. There were no differences in changes between groups. Conclusion: Additional research is needed to determine user experience and acceptance after longer wear period of the AIDANET system. E. Escobar: None. L. Towers: None. G.P. Forlenza: Advisory Panel; Medtronic. Research Support; Medtronic, Dexcom, Inc. Consultant; Dexcom, Inc. Research Support; Insulet Corporation. Consultant; Insulet Corporation. Research Support; Tandem Diabetes Care, Inc. Advisory Panel; Tandem Diabetes Care, Inc. Research Support; Abbott. Advisory Panel; Sequel Med Tech. E.C. Cobry: Advisory Panel; Dexcom, Inc. J.Y. Hosseinipour: None. A. Narayan: None. S.A. Brown: Research Support; Dexcom, Inc., Insulet Corporation, Tandem Diabetes Care, Inc, Tolerion, Roche Diabetes Care. Other Relationship; MannKind Corporation. J.C. Wong: Research Support; Abbott, Dexcom, Inc., Tandem Diabetes Care, Inc.

OBJECTIVE:Multiple states have passed legislation limiting out-of-pocket insulin costs for individuals on private insurance, including Colorado in 2020. Because disruptions in insulin access are life-threatening for people with type 1 diabetes, this study examined the real-world impact of Colorado's law on patient/parent-reported outcomes. RESEARCH DESIGN AND METHODS:Patient/parent-reported frequency of insulin insecurity (insulin rationing, running out early, or finding alternative sources of insulin), cost concerns, and most recent insulin out-of-pocket cost were assessed by a clinic-developed survey. Demographics, A1C, and glycemic time in range (TIR; 70-180 mg/dL) were obtained from medical record review. Linear regression models were fit to compare out-of-pocket costs, A1C, and TIR, adjusting for sex, diabetes duration, race/ethnicity, insurance, and age. RESULTS:Of 184 enrolled participants, 149 responded to insulin insecurity questions, with 34% reporting at least one insulin insecurity behavior. Insulin insecurity was associated with higher monthly insulin costs ($77.60 vs. $19.30, P = 0.004) and A1C (+0.69 ± 0.23%, P = 0.003) and lower TIR (-9.78 ± 4.03%, P = 0.02) compared with insulin security. Similar rates of insecurity were seen in emerging adults (46%, n = 18/39) and those publicly insured (43.5%, n = 10/23). There was no difference in mean copayments between those on public versus private insurance ($39.40 vs. $38.00). CONCLUSION:Despite costs falling below the out-of-pocket cap, insulin insecurity remains common among emerging adults and families of youth with type 1 diabetes and is associated with worse glycemia. Further research into root causes of insecurity, such as limitations on early refills, is required.