Not enough known about fenofibrate's kidney effects in people with Type 2 diabetes.

Globally ≈10% of adults have diabetes, with 80% in disadvantaged regions, hence low-cost renoprotective agents are desirable. Fenofibrate demonstrated microvascular benefits in several cardiovascular end-point diabetes trials, but knowledge of effects in late-stage kidney disease is limited. We report new FIELD substudy data and call for further kidney outcomes data.

Association of circulating fibroblast growth factor 21 levels with all-cause and cardiovascular mortality: The multi-ethnic study of atherosclerosis.

BACKGROUND: Fibroblast growth factor 21 (FGF21) levels are often elevated in cardiovascular disease (CVD). However, no study has assessed its association with cardiovascular and all-cause mortality in a population free of clinically evident CVD. METHODS: A total of 5543 Multi-Ethnic Study of Atherosclerosis (MESA) participants (mean age 62.7 years, 47.5 % male), free of clinically evident CVD at baseline, were studied. From baseline (2000-2002), 1606 deaths (including 387 CVD deaths) were observed over a median follow-up of 17.7 years. Multivariable Cox regression analysis was performed to assess the association of plasma FGF21 levels with mortality. RESULTS: FGF21 levels at baseline were associated with all-cause mortality, even after adjustment for traditional risk factors, including demographic, socioeconomic and cardiovascular risk factors (adjusted hazard ratio 1.08 [95% confidence interval 1.01, 1.16] per 1 SD increase in ln-transformed levels; 1.27 for the highest vs, lowest quartile). Baseline FGF21 levels were significantly associated with both CVD and non-CVD mortality in unadjusted models. However, the association with non-CVD mortality, but not CVD mortality, remained statistically significant after adjusting for covariates. Similar results were obtained in FGF21 quartile analyses and also when using competing risk regression or matched case-control cohort in sensitivity analyses. CONCLUSIONS: In subjects without clinically-evident CVD at baseline, over 17.7 years follow-up there is a modest association of baseline FGF21 levels with all-cause mortality. The finding that this is driven primarily by a significant association with non-CVD mortality over almost two decades merits further investigation.

No relationship between socioeconomic status, education level and development and progression of diabetic retinopathy in type 2 diabetes: a FIELD trial substudy.

In 6002 Australian adults with type 2 diabetes and a median 5-year follow-up in the FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) trial, baseline socioeconomic status (SES) and self-reported education level were not related to development of on-trial sight-threatening diabetic retinopathy. Similarly, in a retinal photography substudy (n = 549), two-step diabetic retinopathy progression was not related to SES or education.

Clinical Pathway for Coronary Atherosclerosis in Patients Without Conventional Modifiable Risk Factors: JACC State-of-the-Art Review.

Reducing the incidence and prevalence of standard modifiable cardiovascular risk factors (SMuRFs) is critical to tackling the global burden of coronary artery disease (CAD). However, a substantial number of individuals develop coronary atherosclerosis despite no SMuRFs. SMuRFless patients presenting with myocardial infarction have been observed to have an unexpected higher early mortality compared to their counterparts with at least 1 SMuRF. Evidence for optimal management of these patients is lacking. We assembled an international, multidisciplinary team to develop an evidence-based clinical pathway for SMuRFless CAD patients. A modified Delphi method was applied. The resulting pathway confirms underlying atherosclerosis and true SMuRFless status, ensures evidence-based secondary prevention, and considers additional tests and interventions for less typical contributors. This dedicated pathway for a previously overlooked CAD population, with an accompanying registry, aims to improve outcomes through enhanced adherence to evidence-based secondary prevention and additional diagnosis of modifiable risk factors observed.

Optimised plasma sample preparation and LC-MS analysis to support large-scale proteomic analysis of clinical trial specimens: Application to the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial.

PURPOSE: Robust, affordable plasma proteomic biomarker workflows are needed for large-scale clinical studies. We evaluated aspects of sample preparation to allow liquid chromatography-mass spectrometry (LC-MS) analysis of more than 1500 samples from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial of adults with type 2 diabetes. METHODS: Using LC-MS with data-independent acquisition we evaluated four variables: plasma protein depletion, EDTA or citrated anti-coagulant blood collection tubes, plasma lipid depletion strategies and plasma freeze-thaw cycles. Optimised methods were applied in a pilot study of FIELD participants. RESULTS: LC-MS of undepleted plasma conducted over a 45 min gradient yielded 172 proteins after excluding immunoglobulin isoforms. Cibachrome-blue-based depletion yielded additional proteins but with cost and time expenses, while immunodepleting albumin and IgG provided few additional identifications. Only minor variations were associated with blood collection tube type, delipidation methods and freeze-thaw cycles. From 65 batches involving over 1500 injections, the median intra-batch quantitative differences in the top 100 proteins of the plasma external standard were less than 2%. Fenofibrate altered seven plasma proteins. CONCLUSIONS AND CLINICAL RELEVANCE: A robust plasma handling and LC-MS proteomics workflow for abundant plasma proteins has been developed for large-scale biomarker studies that balance proteomic depth with time and resource costs.

Factors associated with fragility fractures in type 2 diabetes: An analysis of the randomised controlled Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study.

AIMS: Fracture risk is elevated in some type 2 diabetes patients. Bone fragility may be associated with more clinically severe type 2 diabetes, although prospective studies are lacking. It is unknown which diabetes-related characteristics are independently associated with fracture risk. In this post-hoc analysis of fracture data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial (ISRCTN#64783481), we hypothesised that diabetic microvascular complications are associated with bone fragility. MATERIALS AND METHODS: The FIELD trial randomly assigned 9795 type 2 diabetes participants (aged 50-75 years) to receive oral co-micronised fenofibrate 200 mg (n = 4895) or placebo (n = 4900) daily for a median of 5 years. We used Cox proportional hazards models to identify baseline sex-specific diabetes-related parameters independently associated with incident fractures. RESULTS: Over 49,470 person-years, 137/6138 men experienced 141 fractures and 143/3657 women experienced 145 fractures; incidence rates for the first fracture of 4∙4 (95% CI 3∙8-5∙2) and 7∙7 per 1000 person-years (95% CI 6∙5-9∙1), respectively. Fenofibrate had no effect on fracture outcomes. In men, baseline macrovascular disease (HR 1∙52, 95% CI 1∙05-2∙21, p = 0∙03), insulin use (HR 1∙62, HR 1∙03-2∙55, p = 0∙03), and HDL-cholesterol (HR 2∙20, 95% CI 1∙11-4∙36, p = 0∙02) were independently associated with fracture. In women, independent risk factors included baseline peripheral neuropathy (HR 2∙04, 95% CI 1∙16-3∙59, p = 0∙01) and insulin use (HR 1∙55, 95% CI 1∙02-2∙33, p = 0∙04). CONCLUSIONS: Insulin use and sex-specific complications (in men, macrovascular disease; in women, neuropathy) are independently associated with fragility fractures in adults with type 2 diabetes.

Review and comparison of retinal vessel calibre and geometry software and their application to diabetes, cardiovascular disease, and dementia.

Developments in retinal imaging technologies have enabled the quantitative evaluation of the retinal vasculature. Changes in retinal calibre and/or geometry have been reported in systemic vascular diseases, including diabetes mellitus (DM), cardiovascular disease (CVD), and more recently in neurodegenerative diseases, such as dementia. Several retinal vessel analysis softwares exist, some being disease-specific, others for a broader context. In the research setting, retinal vasculature analysis using semi-automated software has identified associations between retinal vessel calibre and geometry and the presence of or risk of DM and its chronic complications, and of CVD and dementia, including in the general population. In this article, we review and compare the most widely used semi-automated retinal vessel analysis softwares and their associations with ocular imaging findings in common systemic diseases, including DM and its chronic complications, CVD, and dementia. We also provide original data comparing retinal calibre grading in people with Type 1 DM using two softwares, with good concordance.

Impact of Missing Data on the Accuracy of Glucose Metrics from Continuous Glucose Monitoring Assessed Over a 2-Week Period.

Objective: To explore the impact of missing data on the accuracy of continuous glucose monitoring (CGM) metrics collected for a 2-week period in a clinical trial. Research Design and Methods: Simulations were conducted to examine the effect of various patterns of missingness on the accuracy of CGM metrics as compared with a "complete" data set. The proportion of missing data, the "block size" in which the data were missing, and the missing mechanism were modified for each "scenario." The degree of agreement between simulated and "true" glycemic measures under each scenario was presented as R2. Results: Under all missing patterns, R2 declined as the proportion of missing data increased, however, as the "block size" of missing data increased, the percentage of missing data had a more pronounced effect on the agreement between measures. For a 14-day CGM data set to be considered representative for percentage time in range (%TIR), at least 70% of CGM data should be available over at least 10 days (R2 > 0.9). Skewed outcome measures, such as percentage time below range and coefficient of variation, were more affected by missing data than the less skewed measures (%TIR, percentage time above range, mean glucose). Conclusions: Both the degree and pattern of missing data impact upon the accuracy of recommended CGM-derived glycemic measures. In planning research, an understanding of patterns of missing data in the study population is required to gauge the likely effects of missing data on outcome accuracy. Trial registration number: Australian New Zealand Clinic Trials Registry ACTRN12616000753459.

Guideline-based audit of the hospital management of heart failure with reduced ejection fraction.

BACKGROUND: Heart failure is a major burden in Australia in terms of morbidity, mortality and healthcare expenditure. Multiple evidence-based therapies are recommended for heart failure with reduced ejection fraction (HFrEF), but data on physician adherence to therapy guidelines are limited. AIM: To compare use of HFrEF therapies against current evidence-based guidelines in an Australian hospital inpatient population. METHODS: A retrospective review of patients admitted with a principal diagnosis of HFrEF across six metropolitan hospitals in Sydney, Australia, between January 2015 and June 2016. Use of medical and device therapies was compared with guideline recommendations using individual patient indications/contraindications. Readmission and mortality data were collected for a 1-year period following the admission. RESULTS: Of the 1028 HFrEF patients identified, 39 were being managed with palliative intent, leaving 989 patients for the primary analysis. Use of beta-blockers (87.7% actual use/93.6% recommended use) and diuretics (88.4%/99.3%) was high among eligible patients. There were large evidence-practice gaps for angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEI/ARB; 66.4%/89.0%) and aldosterone antagonists (41.0%/77.1%). In absolute terms, use of these therapies each increased by over 11% from admission. Ivabradine (11.5%/21.2%), automated internal cardiac defibrillators (29.5%/66.1%) and cardiac resynchronisation therapy (13.1%/28.7%) were used in a minority of eligible patients. Over the 1-year follow-up period, the mortality rate was 14.8%, and 44.2% of patients were readmitted to hospital at least once. CONCLUSION: Hospitalisation is a key mechanism for initiation of HFrEF therapies. The large evidence-practice gaps for ACEI/ARB and aldosterone antagonists represent potential avenues for improved HFrEF management.

Biomarker Prediction of Complex Coronary Revascularization Procedures in the FOURIER Trial.

BACKGROUND: Biomarkers are known to predict major adverse cardiovascular events. However, the association of biomarkers with complex coronary revascularization procedures or high-risk coronary anatomy at the time of revascularization is not understood. OBJECTIVES: We examined the associations between baseline biomarkers and major coronary events (MCE) and complex revascularization procedures. METHODS: FOURIER was a randomized trial of the proprotein convertase subtilisin-kexin type 9 inhibitor evolocumab vs placebo in 27,564 patients with stable atherosclerosis. We analyzed adjusted associations among the biomarkers, MCE (coronary death, myocardial infarction, or revascularization), and complex revascularization (coronary artery bypass graft or complex percutaneous coronary intervention) using a multimarker score with 1 point assigned for each elevated biomarker (high-sensitivity C-reactive protein ≥2 mg/L; N-terminal pro-B-type natriuretic peptide ≥450 pg/mL; high-sensitivity troponin I ≥6 ng/L; growth-differentiation factor-15 ≥1,800 pg/mL). RESULTS: When patients were grouped by the number of elevated biomarkers (0 biomarkers, n = 6,444; 1-2 biomarkers, n = 12,439; ≥3 biomarkers, n = 2,761), there was a significant graded association between biomarker score and the risk of MCE (intermediate score: HRadj: 1.57 [95% CI: 1.38-1.78]; high score: HRadj: 2.90 [95% CI: 2.47-3.40]), and for complex revascularization (intermediate: HRadj: 1.33 [95% CI: 1.06-1.67]; high score: HRadj: 2.07 [95% CI: 1.52-2.83]) and its components (Ptrend <0.05 for each). The number of elevated biomarkers also correlated with the presence of left main disease, multivessel disease, or chronic total occlusion at the time of revascularization (P < 0.05 for each). CONCLUSIONS: A biomarker-based strategy identifies stable patients at risk for coronary events, including coronary artery bypass graft surgery and complex percutaneous coronary intervention, and predicts high-risk coronary anatomy at the time of revascularization. These findings provide insight into the relationships between cardiovascular biomarkers, coronary anatomical complexity, and incident clinical events. (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk [FOURIER]; NCT01764633).

Hybrid closed-loop therapy with a first-generation system increases confidence and independence in diabetes management in youth with type 1 diabetes.

AIM: Hybrid closed-loop (HCL) therapy improves glycaemic control in adolescents with type 1 diabetes; however, little is known about their lived experience using these systems. The aim of this study was to explore the lived experiences of youth with type 1 diabetes using HCL therapy, and their parents, to provide insight into their lived experiences. METHODS: Adolescents and young adults aged 12-25 years, who used Medtronic MiniMed™ 670G HCL system during a 6-month randomised clinical trial, and their parents, were invited to participate in a semi-structured interview at the end of the study. Open-ended questions were used to explore the lived experiences of families using HCL. The interviews were audio-recorded, transcribed and analysed using thematic analysis to determine the main themes. RESULTS: In all, 17 young people with type 1 diabetes mean ± SD age: 17.5 ± 4.2 years, diabetes duration: 11.0 ± 4.9 years and HbA1c 64 ± 9 mmol/mol (8.0 ± 0.8%) and 10 parents were interviewed. Three themes were identified: (1) 'Developing confidence and trust in the system', (2) 'Reduction in anxiety' and (3) 'Issues with device'. They reported a positive experience using HCL, with improvements in glucose levels and increased independence with diabetes management. However, frustration around the number of alarms and notifications associated with the system were also identified as issues. CONCLUSION: Both youth and parents acknowledged the benefits of this first-generation HCL system in improving glycaemic outcomes and in providing flexibility and independence. These lived experiences provide valuable information in the introduction and provision of targeted education with HCL therapy.

Fenofibrate, which reduces risk of sight-threatening diabetic retinopathy in type 2 diabetes, is associated with early narrowing of retinal venules: a FIELD trial substudy.

Retinal vessel calibre metrics were evaluated at baseline and 2 years in a FIELD substudy (n = 208). Central retinal venule calibre was significantly reduced by fenofibrate and unchanged by placebo. Arteriole metrics did not change. Larger studies relating retinal vessel calibre to future diabetes complications and response to therapy are merited.

Retinopathy risk calculators in the prediction of sight-threatening diabetic retinopathy in type 2 diabetes: A FIELD substudy.

AIMS: To evaluate the risk algorithm by Aspelund et al. for predicting sight-threatening diabetic retinopathy (STDR) in Type 2 diabetes (T2D), and to develop a new STDR prediction model. METHODS: The Aspelund et al. algorithm was used to calculate STDR risk from baseline variables in 1012 participants in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) ophthalmological substudy, compared to on-trial STDR status, and receiver operating characteristic analysis performed. Using multivariable logistic regression, traditional risk factors and fenofibrate allocation as STDR predictors were evaluated, with bootstrap-based optimism-adjusted estimates of predictive performance calculated. RESULTS: STDR developed in 28 participants. The Aspelund et al. algorithm predicted STDR at 2- and 5-years with area under the curve (AUC) 0.86 (95% CI 0.77-0.94) and 0.86 (0.81-0.92), respectively. In the second model STDR risk factors were any DR at baseline (OR 24.0 [95% CI 5.53-104]), HbA1c (OR 1.95 [1.43-2.64]) and male sex (OR 4.34 [1.32-14.3]), while fenofibrate (OR 0.13 [0.05-0.38]) was protective. This model had excellent discriminatory ability (AUC = 0.89). CONCLUSIONS: The algorithm by Aspelund et al. predicts STDR well in the FIELD ophthalmology substudy. Logistic regression analysis found DR at baseline, male sex, and HbA1c were predictive of STDR and, fenofibrate was protective.

Effect of Evolocumab in Patients With Prior Percutaneous Coronary Intervention.

BACKGROUND: Patients with prior percutaneous coronary intervention (PCI) are at high residual risk for multiple types of coronary events within and beyond the stented lesion. This risk might be mitigated by more intensive LDL-C (low-density lipoprotein cholesterol)-lowering beyond just with statin therapy. METHODS: FOURIER (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk) randomized 27 564 patients with stable atherosclerotic disease on statin to the PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitor evolocumab or placebo with a median follow-up of 2.2 years. The end points of interest were major adverse cardiovascular events (MACE; a composite of cardiovascular death, myocardial infarction, stroke, unstable angina or coronary revascularization), and major coronary events (a composite of coronary heart death, myocardial infarction, or coronary revascularization). We compared the risk of MACE and the magnitude of relative and absolute risk reductions with evolocumab in patients with and without prior PCI. RESULTS: Seventeen thousand seventy-three patients had prior PCI. In the placebo arm, those with prior PCI had higher rates of MACE (13.2% versus 8.3%; hazard ratio [HR]adj 1.61 [95% CI, 1.42-1.84]; P<0.0001) and major coronary events (11.5% versus 6.0%; HRadj, 1.72 [95% CI, 1.49-1.99]; P<0.0001). Relative risk reductions with evolocumab were similar in patients with and without prior PCI (MACE: HR, 0.84 [0.77-0.91] versus HR, 0.88 [0.77-1.01]; Pinteraction 0.51; major coronary events: HR, 0.82 [0.75-0.90] versus HR, 0.88 [0.75-1.04]; Pinteraction 0.42). Absolute risk reductions for MACE were 2.0% versus 0.9% (Pinteraction 0.14) and for major coronary events 2.0% versus 0.7% (Pinteraction 0.045). In those with prior PCI, the effect of evolocumab on coronary revascularization (HR, 0.76 [0.69-0.85]) was directionally consistent across types of revascularization procedures: coronary artery bypass grafting (HR, 0.71 [0.54-0.94]); any PCI (HR, 0.77 [0.69-0.86]); PCI for de novo lesions (HR, 0.76 [0.66-0.88]); and PCI for stent failure or graft lesions (HR, 0.76 [0.63-0.91]). CONCLUSIONS: Evolocumab reduces the risk of MACE in patients with prior PCI including the risk of coronary revascularization, with directionally consistent effects across several types of revascularization procedures, including coronary artery bypass grafting and PCI for stent or graft failure. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01764633.

Driving with Type 1 Diabetes: Real-World Evidence to Support Starting Glucose Level and Frequency of Monitoring During Journeys.

There is limited evidence supporting the recommendation that drivers with insulin-treated diabetes need to start journeys with glucose >90 mg/dL. Glucose levels of drivers with type 1 diabetes were monitored for 3 weeks using masked continuous glucose monitoring (CGM). Eighteen drivers (median [IQR] age 40 [35, 51] years; 11 men) undertook 475 trips (duration 15 [13, 21] min). Hypoglycemia did not occur in any trip starting with glucose >90 mg/dL (92%; n = 436). Thirteen drivers recorded at least one trip (total n = 39) starting with glucose <90 mg/dL. Among these, driving glucose was <70 mg/dL in five drivers (38%) during 10 trips (26%). Among five drivers (28%), a ≥ 36 mg/dL drop was observed within 20 min of starting their journey. Journey duration was positively associated with maximum glucose change. These findings support current guidelines to start driving with glucose >90 mg/dL, and to be aware that glucose levels may change significantly within 20 min. A CGM-based, in-vehicle display could provide glucose information and alerts that are compatible with safe driving. Clinical Trial Registration number: ACTRN12617000520336.

Shortened Leukocyte Telomere Length Is Associated With Glycemic Progression in Type 2 Diabetes: A Prospective and Mendelian Randomization Analysis.

OBJECTIVE: Several studies support associations between relative leukocyte telomere length (rLTL), a biomarker of biological aging and type 2 diabetes. This study investigates the relationship between rLTL and the risk of glycemic progression in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: In this cohort study, consecutive Chinese patients with type 2 diabetes (N = 5,506) from the Hong Kong Diabetes Register with stored baseline DNA and available follow-up data were studied. rLTL was measured using quantitative PCR. Glycemic progression was defined as the new need for exogenous insulin. RESULTS: The mean (SD) age of the 5,349 subjects was 57.0 (13.3) years, and mean (SD) follow-up was 8.8 (5.4) years. Baseline rLTL was significantly shorter in the 1,803 subjects who progressed to insulin requirement compared with the remaining subjects (4.43 ± 1.16 vs. 4.69 ± 1.20). Shorter rLTL was associated with a higher risk of glycemic progression (hazard ratio [95% CI] for each unit decrease [to ∼0.2 kilobases]: 1.10 [1.06-1.14]), which remained significant after adjusting for confounders. Baseline rLTL was independently associated with glycemic exposure during follow-up (ß = -0.05 [-0.06 to -0.04]). Each 1-kilobase decrease in absolute LTL was on average associated with a 1.69-fold higher risk of diabetes progression (95% CI 1.35-2.11). Two-sample Mendelian randomization analysis showed per 1-unit genetically decreased rLTL was associated with a 1.38-fold higher risk of diabetes progression (95% CI 1.12-1.70). CONCLUSIONS: Shorter rLTL was significantly associated with an increased risk of glycemic progression in individuals with type 2 diabetes, independent of established risk factors. Telomere length may be a useful biomarker for glycemic progression in people with type 2 diabetes.

Relative leucocyte telomere length is associated with incident end-stage kidney disease and rapid decline of kidney function in type 2 diabetes: analysis from the Hong Kong Diabetes Register.

AIMS/HYPOTHESIS: Few large-scale prospective studies have investigated associations between relative leucocyte telomere length (rLTL) and kidney dysfunction in individuals with type 2 diabetes. We examined relationships between rLTL and incident end-stage kidney disease (ESKD) and the slope of eGFR decline in Chinese individuals with type 2 diabetes. METHODS: We studied 4085 Chinese individuals with type 2 diabetes observed between 1995 and 2007 in the Hong Kong Diabetes Register with stored baseline DNA and available follow-up data. rLTL was measured using quantitative PCR. ESKD was diagnosed based on the ICD-9 code and eGFR. RESULTS: In this cohort (mean ± SD age 54.3 ± 12.6 years) followed up for 14.1 ± 5.3 years, 564 individuals developed incident ESKD and had shorter rLTL at baseline (4.2 ± 1.2 vs 4.7 ± 1.2, p < 0.001) than the non-progressors (n = 3521). On Cox regression analysis, each ∆∆Ct decrease in rLTL was associated with an increased risk of incident ESKD (HR 1.21 [95% CI 1.13, 1.30], p < 0.001); the association remained significant after adjusting for baseline age, sex, HbA1c, lipids, renal function and other risk factors (HR 1.11 [95% CI 1.03, 1.19], p = 0.007). Shorter rLTL at baseline was associated with rapid decline in eGFR (>4% per year) during follow-up (unadjusted OR 1.22 [95% CI 1.15, 1.30], p < 0.001; adjusted OR 1.09 [95% CI 1.01, 1.17], p = 0.024). CONCLUSIONS/INTERPRETATION: rLTL is independently associated with incident ESKD and rapid eGFR loss in individuals with type 2 diabetes. Telomere length may be a useful biomarker for the progression of kidney function and ESKD in type 2 diabetes.

Effect of a Hybrid Closed-Loop System on Glycemic and Psychosocial Outcomes in Children and Adolescents With Type 1 Diabetes: A Randomized Clinical Trial.

Importance: Hybrid closed-loop (HCL) therapy has improved glycemic control in children and adolescents with type 1 diabetes; however, the efficacy of HCL on glycemic and psychosocial outcomes has not yet been established in a long-term randomized clinical trial. Objective: To determine the percentage of time spent in the target glucose range using HCL vs current conventional therapies of continuous subcutaneous insulin infusion or multiple daily insulin injections with or without continuous glucose monitoring (CGM). Design, Setting, and Participants: This 6-month, multicenter, randomized clinical trial included 172 children and adolescents with type 1 diabetes; patients were recruited between April 18, 2017, and October 4, 2019, in Australia. Data were analyzed from July 25, 2020, to February 26, 2021. Interventions: Eligible participants were randomly assigned to either the control group for conventional therapy (continuous subcutaneous insulin infusion or multiple daily insulin injections with or without CGM) or the intervention group for HCL therapy. Main Outcomes and Measures: The primary outcome was the percentage of time in range (TIR) within a glucose range of 70 to 180 mg/dL, measured by 3-week masked CGM collected at the end of the study in both groups. Secondary outcomes included CGM metrics for hypoglycemia, hyperglycemia, and glycemic variability and psychosocial measures collected by validated questionnaires. Results: A total of 135 patients (mean [SD] age, 15.3 [3.1] years; 76 girls [56%]) were included, with 68 randomized to the control group and 67 to the HCL group. Patients had a mean (SD) diabetes duration of 7.7 (4.3) years and mean hemoglobin A1c of 64 (11) mmol/mol, with 110 participants (81%) receiving continuous subcutaneous insulin infusion and 72 (53%) receiving CGM. In the intention-to-treat analyses, TIR increased from a mean (SD) of 53.1% (13.0%) at baseline to 62.5% (12.0%) at the end of the study in the HCL group and from 54.6% (12.5%) to 56.1% (12.2%) in the control group, with a mean adjusted difference between the 2 groups of 6.7% (95% CI, 2.7%-10.8%; P = .002). Hybrid closed-loop therapy also reduced the time that patients spent in a hypoglycemic (<70 mg/dL) range (difference, -1.9%; 95% CI, -2.5% to -1.3%) and improved glycemic variability (coefficient of variation difference, -5.7%; 95% CI, -10.2% to -0.9%). Hybrid closed-loop therapy was associated with improved diabetes-specific quality of life (difference, 4.4 points; 95% CI, 0.4-8.4 points), with no change in diabetes distress. There were no episodes of severe hypoglycemia or diabetic ketoacidosis in either group. Conclusions and Relevance: In this randomized clinical trial, 6 months of HCL therapy significantly improved glycemic control and quality of life compared with conventional therapy in children and adolescents with type 1 diabetes. Trial Registration: ANZCTR identifier: ACTRN12616000753459.