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2.
Artigo em Inglês | MEDLINE | ID: mdl-32069094

RESUMO

We performed a literature review of composite metrics for describing the quality of glycemic control, as measured by continuous glucose monitors (CGMs). Nine composite metrics that describe CGM data were identified. They are described in detail along with their advantages and disadvantages. The primary benefit to using composite metrics in clinical practice is to be able to quickly evaluate a patient's glycemic control in the form of a single number that accounts for multiple dimensions of glycemic control. Very little data exist about (1) how to select the optimal components of composite metrics for CGM; (2) how to best score individual components of composite metrics; and (3) how to correlate composite metric scores with empiric outcomes. Nevertheless, composite metrics are an attractive type of scoring system to present clinicians with a single number that accounts for many dimensions of their patients' glycemia. If a busy health care professional is looking for a single-number summary statistic to describe glucose levels monitored by a CGM, then a composite metric has many attractive features.

4.
N Engl J Med ; 381(18): 1707-1717, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31618560

RESUMO

BACKGROUND: Closed-loop systems that automate insulin delivery may improve glycemic outcomes in patients with type 1 diabetes. METHODS: In this 6-month randomized, multicenter trial, patients with type 1 diabetes were assigned in a 2:1 ratio to receive treatment with a closed-loop system (closed-loop group) or a sensor-augmented pump (control group). The primary outcome was the percentage of time that the blood glucose level was within the target range of 70 to 180 mg per deciliter (3.9 to 10.0 mmol per liter), as measured by continuous glucose monitoring. RESULTS: A total of 168 patients underwent randomization; 112 were assigned to the closed-loop group, and 56 were assigned to the control group. The age range of the patients was 14 to 71 years, and the glycated hemoglobin level ranged from 5.4 to 10.6%. All 168 patients completed the trial. The mean (±SD) percentage of time that the glucose level was within the target range increased in the closed-loop group from 61±17% at baseline to 71±12% during the 6 months and remained unchanged at 59±14% in the control group (mean adjusted difference, 11 percentage points; 95% confidence interval [CI], 9 to 14; P<0.001). The results with regard to the main secondary outcomes (percentage of time that the glucose level was >180 mg per deciliter, mean glucose level, glycated hemoglobin level, and percentage of time that the glucose level was <70 mg per deciliter or <54 mg per deciliter [3.0 mmol per liter]) all met the prespecified hierarchical criterion for significance, favoring the closed-loop system. The mean difference (closed loop minus control) in the percentage of time that the blood glucose level was lower than 70 mg per deciliter was -0.88 percentage points (95% CI, -1.19 to -0.57; P<0.001). The mean adjusted difference in glycated hemoglobin level after 6 months was -0.33 percentage points (95% CI, -0.53 to -0.13; P = 0.001). In the closed-loop group, the median percentage of time that the system was in closed-loop mode was 90% over 6 months. No serious hypoglycemic events occurred in either group; one episode of diabetic ketoacidosis occurred in the closed-loop group. CONCLUSIONS: In this 6-month trial involving patients with type 1 diabetes, the use of a closed-loop system was associated with a greater percentage of time spent in a target glycemic range than the use of a sensor-augmented insulin pump. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases; iDCL ClinicalTrials.gov number, NCT03563313.).


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Sistemas de Infusão de Insulina , Insulina/administração & dosagem , Pâncreas Artificial , Adolescente , Adulto , Idoso , Glicemia/análise , Diabetes Mellitus Tipo 1/sangue , Desenho de Equipamento , Feminino , Hemoglobina A Glicada/análise , Humanos , Hipoglicemiantes/efeitos adversos , Insulina/efeitos adversos , Sistemas de Infusão de Insulina/efeitos adversos , Masculino , Pessoa de Meia-Idade , Pâncreas Artificial/efeitos adversos , Adulto Jovem
5.
Pediatr Diabetes ; 20(6): 759-768, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31099946

RESUMO

OBJECTIVE: Artificial pancreas (AP) systems have been shown to improve glycemic control throughout the day and night in adults, adolescents, and children. However, AP testing remains limited during intense and prolonged exercise in adolescents and children. We present the performance of the Tandem Control-IQ AP system in adolescents and children during a winter ski camp study, where high altitude, low temperature, prolonged intense activity, and stress challenged glycemic control. METHODS: In a randomized controlled trial, 24 adolescents (ages 13-18 years) and 24 school-aged children (6-12 years) with Type 1 diabetes (T1D) participated in a 48 hours ski camp (∼5 hours skiing/day) at three sites: Wintergreen, VA; Kirkwood, and Breckenridge, CO. Study participants were randomized 1:1 at each site. The control group used remote monitored sensor-augmented pump (RM-SAP), and the experimental group used the t: slim X2 with Control-IQ Technology AP system. All subjects were remotely monitored 24 hours per day by study staff. RESULTS: The Control-IQ system improved percent time within range (70-180 mg/dL) over the entire camp duration: 66.4 ± 16.4 vs 53.9 ± 24.8%; P = .01 in both children and adolescents. The AP system was associated with a significantly lower average glucose based on continuous glucose monitor data: 161 ± 29.9 vs 176.8 ± 36.5 mg/dL; P = .023. There were no differences between groups for hypoglycemia exposure or carbohydrate interventions. There were no adverse events. CONCLUSIONS: The use of the Control-IQ AP improved glycemic control and safely reduced exposure to hyperglycemia relative to RM-SAP in pediatric patients with T1D during prolonged intensive winter sport activities.

6.
Diabetes Technol Ther ; 21(6): 356-363, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31095423

RESUMO

Background: Typically, closed-loop control (CLC) studies excluded patients with significant hypoglycemia. We evaluated the effectiveness of hybrid CLC (HCLC) versus sensor-augmented pump (SAP) in reducing hypoglycemia in this high-risk population. Methods: Forty-four subjects with type 1 diabetes, 25 women, 37 ± 2 years old, HbA1c 7.4% ± 0.2% (57 ± 1.5 mmol/mol), diabetes duration 19 ± 2 years, on insulin pump, were enrolled at the University of Virginia (N = 33) and Stanford University (N = 11). Eligibility: increased risk of hypoglycemia confirmed by 1 week of blinded continuous glucose monitor (CGM); randomized to 4 weeks of home use of either HCLC or SAP. Primary/secondary outcomes: risk for hypoglycemia measured by the low blood glucose index (LBGI)/CGM-based time in ranges. Results: Values reported: mean ± standard deviation. From baseline to the final week of study: LBGI decreased more on HCLC (2.51 ± 1.17 to 1.28 ± 0.5) than on SAP (2.1 ± 1.05 to 1.79 ± 0.98), P < 0.001; percent time below 70 mg/dL (3.9 mmol/L) decreased on HCLC (7.2% ± 5.3% to 2.0% ± 1.4%) but not on SAP (5.8% ± 4.7% to 4.8% ± 4.5%), P = 0.001; percent time within the target range 70-180 mg/dL (3.9-10 mmol/L) increased on HCLC (67.8% ± 13.5% to 78.2% ± 10%) but decreased on SAP (65.6% ± 12.9% to 59.6% ± 16.5%), P < 0.001; percent time above 180 mg/dL (10 mmol/L) decreased on HCLC (25.1% ± 15.3% to 19.8% ± 10.1%) but increased on SAP (28.6% ± 14.6% to 35.6% ± 17.6%), P = 0.009. Mean glucose did not change significantly on HCLC (144.9 ± 27.9 to 143.8 ± 14.4 mg/dL [8.1 ± 1.6 to 8.0 ± 0.8 mmol/L]) or SAP (152.5 ± 24.3 to 162.4 ± 28.2 [8.5 ± 1.4 to 9.0 ± 1.6]), P = ns. Conclusions: Compared with SAP therapy, HCLC reduced the risk and frequency of hypoglycemia, while improving time in target range and reducing hyperglycemia in people at moderate to high risk of hypoglycemia.

7.
Diabetes Technol Ther ; 21(2): 73-80, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30649925

RESUMO

BACKGROUND: Use of artificial pancreas (AP) requires seamless interaction of device components, such as continuous glucose monitor (CGM), insulin pump, and control algorithm. Mobile AP configurations also include a smartphone as computational hub and gateway to cloud applications (e.g., remote monitoring and data review and analysis). This International Diabetes Closed-Loop study was designed to demonstrate and evaluate the operation of the inControl AP using different CGMs and pump modalities without changes to the user interface, user experience, and underlying controller. METHODS: Forty-three patients with type 1 diabetes (T1D) were enrolled at 10 clinical centers (7 United States, 3 Europe) and 41 were included in the analyses (39% female, >95% non-Hispanic white, median T1D duration 16 years, median HbA1c 7.4%). Two CGMs and two insulin pumps were tested by different study participants/sites using the same system hub (a smartphone) during 2 weeks of in-home use. RESULTS: The major difference between the system components was the stability of their wireless connections with the smartphone. The two sensors achieved similar rates of connectivity as measured by percentage time in closed loop (75% and 75%); however, the two pumps had markedly different closed-loop adherence (66% vs. 87%). When connected, all system configurations achieved similar glycemic outcomes on AP control (73% [mean] time in range: 70-180 mg/dL, and 1.7% [median] time <70 mg/dL). CONCLUSIONS: CGMs and insulin pumps can be interchangeable in the same Mobile AP system, as long as these devices achieve certain levels of reliability and wireless connection stability.


Assuntos
Glicemia/análise , Diabetes Mellitus Tipo 1/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Sistemas de Infusão de Insulina , Insulina/administração & dosagem , Pâncreas Artificial , Adolescente , Adulto , Idoso , Algoritmos , Automonitorização da Glicemia , Diabetes Mellitus Tipo 1/sangue , Feminino , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Smartphone , Resultado do Tratamento , Adulto Jovem
8.
Diabetes Technol Ther ; 20(8): 531-540, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29979618

RESUMO

BACKGROUND: Glucose variability (GV) remains a key limiting factor in the success of diabetes management. While new technologies, for example, accurate continuous glucose monitoring (CGM) and connected insulin delivery devices, are now available, current treatment standards fail to leverage the wealth of information generated. Expert systems, from automated insulin delivery to advisory systems, are a key missing element to richer, more personalized, glucose management in diabetes. METHODS: Twenty four subjects with type 1 diabetes mellitus (T1DM), 15 women, 37 ± 11 years of age, hemoglobin A1c 7.2% ± 1%, total daily insulin (TDI) 46.7 ± 22.3 U, using either an insulin pump or multiple daily injections with carbohydrate counting, completed two randomized crossover 48-h visits at the University of Virginia, wearing Dexcom G4 CGM, and using either usual care or the UVA decision support system (DSS). DSS consisted of a combination of automated insulin titration, bolus calculation, and CHO treatment advice. During each admission, participants were exposed to a variety of meal sizes and contents and two 45-min bouts of exercise. GV and glucose control were assessed using CGM. RESULTS: The use of DSS significantly reduced GV (coefficient of variation: 0.36 ± 08. vs. 0.33 ± 0.06, P = 0.045) while maintaining glycemic control (average CGM: 155.2 ± 27.1 mg/dL vs. 155.2 ± 23.2 mg/dL), by reducing hypoglycemia exposure (%<70 mg/dL: 3.8% ± 4.6% vs. 1.8% ± 2%, P = 0.018), with nonsignificant trends toward reduction of significant hyperglycemia overnight (%>250 mg/dL: 5.3% ± 9.5% vs. 1.9% ± 4.6%) and at mealtime (11.3% ± 14.8% vs. 5.8% ± 9.1%). CONCLUSIONS: A CGM/insulin informed advisory system proved to be safe and feasible in a cohort of 24 T1DM subjects. Use of the system may result in reduced GV and improved protection against hypoglycemia.


Assuntos
Glicemia/análise , Diabetes Mellitus Tipo 1/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Sistemas de Infusão de Insulina , Insulina/administração & dosagem , Adolescente , Adulto , Automonitorização da Glicemia/instrumentação , Criança , Estudos Cross-Over , Sistemas de Apoio a Decisões Clínicas , Diabetes Mellitus Tipo 1/sangue , Relação Dose-Resposta a Droga , Feminino , Hemoglobina A Glicada/análise , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Resultado do Tratamento , Adulto Jovem
9.
Diabetes Care ; 41(8): 1681-1688, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29898901

RESUMO

OBJECTIVE: Cleared blood glucose monitors (BGMs) for personal use may not always deliver levels of accuracy currently specified by international and U.S. regulatory bodies. This study's objective was to assess the accuracy of 18 such systems cleared by the U.S. Food and Drug Administration representing approximately 90% of commercially available systems used from 2013 to 2015. RESEARCH DESIGN AND METHODS: A total of 1,035 subjects were recruited to have a capillary blood glucose (BG) level measured on six different systems and a reference capillary sample prepared for plasma testing at a reference laboratory. Products were obtained from consumer outlets and tested in three triple-blinded studies. Each of the three participating clinical sites tested a different set of six systems for each of the three studies in a round-robin. In each study, on average, a BGM was tested on 115 subjects. A compliant BG result was defined as within 15% of a reference plasma value (for BG ≥100 mg/dL [5.55 mmol/L]) or within 15 mg/dL (0.83 mmol/L) (for BG <100 mg/dL [5.55 mmol/L]). The proportion of compliant readings in each study was compared against a predetermined accuracy standard similar to, but more lenient than, current regulatory standards. Other metrics of accuracy included the overall compliance proportion; the proportion of extreme outlier readings differing from the reference value by >20%; modified Bland-Altman analysis including average bias, coefficient of variation, and 95% limits of agreement; and proportion of readings with no clinical risk as determined by the Surveillance Error Grid. RESULTS: The different accuracy metrics produced almost identical BGM rankings. Six of the 18 systems met the predetermined accuracy standard in all three studies, 5 systems met it in two studies, and 3 met it in one study. Four BGMs did not meet the accuracy standard in any of the three studies. CONCLUSIONS: Cleared BGMs do not always meet the level of analytical accuracy currently required for regulatory clearance. This information could assist patients, professionals, and payers in choosing products and regulators in evaluating postclearance performance.


Assuntos
Glicemia/análise , Diabetes Mellitus/sangue , Equipamentos e Provisões/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Automonitorização da Glicemia/instrumentação , Automonitorização da Glicemia/normas , Comércio , Método Duplo-Cego , Feminino , Hematócrito/instrumentação , Hematócrito/normas , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Estado Pré-Diabético/sangue , Valores de Referência , Reprodutibilidade dos Testes , Estados Unidos , United States Food and Drug Administration , Adulto Jovem
10.
J Diabetes Sci Technol ; 12(2): 273-281, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29451021

RESUMO

BACKGROUND: A new version of the UVA/Padova Type 1 Diabetes (T1D) Simulator is presented which provides a more realistic testing scenario. The upgrades to the previous simulator, which was accepted by the Food and Drug Administration in 2013, are described. METHOD: Intraday variability of insulin sensitivity (SI) has been modeled, based on clinical T1D data, accounting for both intra- and intersubject variability of daily SI. Thus, time-varying distributions of both subject's basal insulin infusion and insulin-to-carbohydrate ratio were calculated and made available to the user. A model of "dawn" phenomenon based on clinical T1D data has been also included. Moreover, the model of subcutaneous insulin delivery has been updated with a recently developed model of commercially available fast-acting insulin analogs. Models of both intradermal and inhaled insulin pharmacokinetics have been included. Finally, new models of error affecting continuous glucose monitoring and self-monitoring of blood glucose devices have been added. RESULTS: One hundred in silico adults, adolescent, and children have been generated according to the above modifications. The new simulator reproduces the intraday glucose variability observed in clinical data, also describing the nocturnal glucose increase, and the simulated insulin profiles reflect real life data. CONCLUSIONS: The new modifications introduced in the T1D simulator allow to extend its domain of validity from "single-meal" to "single-day" scenarios, thus enabling a more realistic framework for in silico testing of advanced diabetes technologies including glucose sensors, new insulin molecules and artificial pancreas.


Assuntos
Simulação por Computador , Diabetes Mellitus Tipo 1 , Adolescente , Adulto , Glicemia , Criança , Humanos , Resistência à Insulina
11.
J Diabetes Sci Technol ; 12(2): 311-317, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28942668

RESUMO

AIMS: In type 1 diabetes (T1D), repeated hypoglycemic episodes may reduce hormonal defenses and increase the risk for severe hypoglycemia. In this work, we investigate the effect of a structured hyper/hypoglycemic metabolic challenge on the postintervention glucose variability in T1D subjects studied at home. METHODS: Thirty T1D subjects using insulin pump were monitored with blood glucose meters (SMBG) during a 1-month observation period. After 2 weeks of monitoring, participants were admitted at the University of Virginia Clinical Research Unit to undergo an 8-hour metabolic challenge. The intervention was designed to create hyperglycemia shortly followed by hypoglycemia, mimicking a real-life scenario of underbolused meal followed by overcorrection. After the intervention, subjects were monitored for 2 more weeks. Glycemic variability was assessed before and after the challenge using the low blood glucose index (LBGI). Glucagon counterregulation (GCR) response to induced hypoglycemia was also measured. LBGI variation and GCR were linked to prior exposure to hypoglycemia. RESULTS: Subjects significantly exposed to hypoglycemia in the 2 weeks before the intervention had a significant increase of postchallenge LBGI ( P < .001) and lower GCR response ( P < .05). Recent occurrence of hypoglycemia and number of years not using an insulin pump were identified as significant predictors of postchallenge LBGI ( P < .001). CONCLUSION: Glycemic swings, a common result of suboptimal insulin treatment, have a significant impact on future (days) glycemic control in T1D subjects with a recent history of hypoglycemia, as measured in the field. Choice of past insulin therapy may also mediate this effect.


Assuntos
Glicemia , Diabetes Mellitus Tipo 1/sangue , Hiperglicemia/sangue , Hipoglicemia/sangue , Adulto , Diabetes Mellitus Tipo 1/tratamento farmacológico , Feminino , Humanos , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Sistemas de Infusão de Insulina , Masculino , Pessoa de Meia-Idade
12.
Diabetes Care ; 40(12): 1644-1650, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28855239

RESUMO

OBJECTIVE: Intense exercise is a major challenge to the management of type 1 diabetes (T1D). Closed-loop control (CLC) systems (artificial pancreas) improve glycemic control during limited intensity and short duration of physical activity (PA). However, CLC has not been tested during extended vigorous outdoor exercise common among adolescents. RESEARCH DESIGN AND METHODS: Skiing presents unique metabolic challenges: intense prolonged PA, cold, altitude, and stress/fear/excitement. In a randomized controlled trial, 32 adolescents with T1D (ages 10-16 years) participated in a 5-day ski camp (∼5 h skiing/day) at two sites: Wintergreen, VA, and Breckenridge, CO. Participants were randomized to the University of Virginia CLC system or remotely monitored sensor-augmented pump (RM-SAP). The CLC and RM-SAP groups were coarsely paired by age and hemoglobin A1c (HbA1c). All subjects were remotely monitored 24 h per day by the study physicians and clinical team. RESULTS: Compared with physician-monitored open loop, percent time in range (70-180 mg/dL) improved using CLC: 71.3 vs. 64.7% (+6.6% [95% CI 1-12]; P = 0.005), with maximum effect late at night. Hypoglycemia exposure and carbohydrate treatments were improved overall (P = 0.001 and P = 0.007) and during the daytime with strong ski level effects (P = 0.0001 and P = 0.006); ski/snowboard proficiency was balanced between groups but with a very strong site effect: naive in Virginia and experienced in Colorado. There was no adverse event associated with CLC; the participants' feedback was overwhelmingly positive. CONCLUSIONS: CLC in adolescents with T1D improved glycemic control and reduced exposure to hypoglycemia during prolonged intensive winter sport activities, despite the added challenges of cold and altitude.


Assuntos
Automonitorização da Glicemia , Diabetes Mellitus Tipo 1/terapia , Exercício , Pâncreas Artificial , Esqui , Adolescente , Glicemia/metabolismo , Índice de Massa Corporal , Criança , Temperatura Baixa , Colorado , Diabetes Mellitus Tipo 1/sangue , Hemoglobina A Glicada/metabolismo , Humanos , Hipoglicemia/etiologia , Hipoglicemia/terapia , Estações do Ano , Resultado do Tratamento , Virginia
13.
J Clin Endocrinol Metab ; 102(10): 3674-3682, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28666360

RESUMO

Context: Closed-loop control (CLC) for the management of type 1 diabetes (T1D) is a novel method for optimizing glucose control, and strategies for individualized implementation are being developed. Objective: To analyze glycemic control in an overnight CLC system designed to "reset" the patient to near-normal glycemic targets every morning. Design: Randomized, crossover, multicenter clinical trial. Participants: Forty-four subjects with T1D requiring insulin pump therapy. Intervention: Sensor-augmented pump therapy (SAP) at home vs 5 nights of CLC (active from 23:00 to 07:00) in a supervised outpatient setting (research house or hotel), with a substudy of 5 nights of CLC subsequently at home. Main Outcome Measure: The percentage of time spent in the target range (70 to 180 mg/dL measured using a continuous glucose monitor). Results: Forty subjects (age, 45.5 ± 9.5 years; hemoglobin A1c, 7.4% ± 0.8%) completed the study. The time in the target range (70 to 180 mg/dL) significantly improved in CLC vs SAP over 24 hours (78.3% vs 71.4%; P = 0.003) and overnight (85.7% vs 67.6%; P < 0.001). The time spent in a hypoglycemic range (<70 mg/dL) decreased significantly in the CLC vs SAP group over 24 hours (2.5% vs 4.3%; P = 0.002) and overnight (0.9% vs 3.2%; P < 0.001). The mean glucose level at 07:00 was lower with CLC than with SAP (123.7 vs 145.3 mg/dL; P < 0.001). The substudy at home, involving 10 T1D subjects, showed similar trends with an increased time in target (70 to 180 mg/dL) overnight (75.2% vs 62.2%; P = 0.07) and decreased time spent in the hypoglycemic range (<70 mg/dL) overnight in CLC vs SAP (0.6% vs 3.7%; P = 0.03). Conclusion: Overnight-only CLC increased the time in the target range over 24 hours and decreased the time in hypoglycemic range over 24 hours in a supervised outpatient setting. A pilot extension study at home showed a similar nonsignificant trend.


Assuntos
Glicemia/efeitos dos fármacos , Ritmo Circadiano , Diabetes Mellitus Tipo 1/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Sistemas de Infusão de Insulina , Insulina/administração & dosagem , Adulto , Glicemia/análise , Automonitorização da Glicemia/instrumentação , Automonitorização da Glicemia/métodos , Ritmo Circadiano/efeitos dos fármacos , Estudos Cross-Over , Diabetes Mellitus Tipo 1/sangue , Feminino , Hemoglobina A Glicada , Humanos , Hipoglicemiantes/efeitos adversos , Insulina/efeitos adversos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
14.
Diabetes Technol Ther ; 19(5): 293-298, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28426239

RESUMO

BACKGROUND: Young children 5-8 years old with type 1 diabetes (T1D) exhibit clear needs for improved glycemic control but may be limited in their ability to safely interact with an artificial pancreas system. Our goal was to evaluate the safety and performance of an artificial pancreas (AP) system among young children with T1D. RESEARCH DESIGN AND METHODS: In a randomized, crossover trial, children with T1D age 5-8 years were enrolled to receive on separate study periods (in random order) either the UVa AP using the DiAs Control Platform software with child-resistant lock-out screens (followed as an out-patient admission) or their usual insulin pump+continuous glucose monitor (CGM) care at home. Hypoglycemic events and CGM tracings were compared between the two 68-h study periods. All analyses were adjusted for level of physical activity as tracked using Fitbit devices. RESULTS: Twelve participants (median age 7 years, n = 6 males) completed the trial. Compared to home care, the AP admission resulted in increased time with blood glucose (BG) 70-180 mg/dL (73% vs. 47%) and lower mean BG (152 mg/dL vs. 190 mg/dL), both P < 0.001 after adjustment for activity. Occurrence of hypoglycemia was similar between sessions without differences in time <70 mg/dL (AP 1.1% ± 1.1%; home 1.6% ± 1.2%). There were no adverse events during the AP or home study periods. CONCLUSIONS: Use of an AP in young children was safe and resulted in improved mean BG without increased hypoglycemia. This suggests that AP use in young children is safe and improves overall diabetes control. ClinicalTrials.gov registration number: NCT02750267.


Assuntos
Glicemia/análise , Diabetes Mellitus Tipo 1/terapia , Hiperglicemia/prevenção & controle , Hipoglicemia/prevenção & controle , Pâncreas Artificial , Atividades Cotidianas , Criança , Comportamento Infantil , Pré-Escolar , Segurança Computacional , Estudos Cross-Over , Diabetes Mellitus Tipo 1/sangue , Exercício , Estudos de Viabilidade , Feminino , Monitores de Aptidão Física , Hospitais Universitários , Humanos , Hipoglicemia/induzido quimicamente , Masculino , Ambulatório Hospitalar , Pâncreas Artificial/efeitos adversos , Virginia
15.
Nat Rev Endocrinol ; 13(7): 425-436, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28304392

RESUMO

As intensive treatment to lower levels of HbA1c characteristically results in an increased risk of hypoglycaemia, patients with diabetes mellitus face a life-long optimization problem to reduce average levels of glycaemia and postprandial hyperglycaemia while simultaneously avoiding hypoglycaemia. This optimization can only be achieved in the context of lowering glucose variability. In this Review, I discuss topics that are related to the assessment, quantification and optimal control of glucose fluctuations in diabetes mellitus. I focus on markers of average glycaemia and the utility and/or shortcomings of HbA1c as a 'gold-standard' metric of glycaemic control; the notion that glucose variability is characterized by two principal dimensions, amplitude and time; measures of glucose variability that are based on either self-monitoring of blood glucose data or continuous glucose monitoring (CGM); and the control of average glycaemia and glucose variability through the use of pharmacological agents or closed-loop control systems commonly referred to as the 'artificial pancreas'. I conclude that HbA1c and the various available metrics of glucose variability reflect the management of diabetes mellitus on different timescales, ranging from months (for HbA1c) to minutes (for CGM). Comprehensive assessment of the dynamics of glycaemic fluctuations is therefore crucial for providing accurate and complete information to the patient, physician, automated decision-support or artificial-pancreas system.


Assuntos
Automonitorização da Glicemia/métodos , Glicemia/análise , Diabetes Mellitus/sangue , Diabetes Mellitus/diagnóstico , Hemoglobina A Glicada/análise , Algoritmos , Biomarcadores , Diabetes Mellitus/terapia , Humanos
16.
Pediatr Diabetes ; 18(7): 540-546, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27734563

RESUMO

OBJECTIVE: To evaluate the safety and performance of using a heart rate (HR) monitor to inform an artificial pancreas (AP) system during exercise among adolescents with type 1 diabetes (T1D). MATERIALS AND METHODS: In a randomized, cross-over trial, adolescents with T1D age 13 - 18 years were enrolled to receive on separate days either the unmodified UVa AP (stdAP) or an AP system connected to a portable HR monitor (AP-HR) that triggered an exercise algorithm for blood glucose (BG) control. During admissions participants underwent a structured exercise regimen. Hypoglycemic events and CGM tracings were compared between the two admissions, during exercise and for the full 24-hour period. RESULTS: Eighteen participants completed the trial. While number of hypoglycemic events during exercise and rest was not different between visits (0.39 AP-HR vs 0.50 stdAP), time below 70 mg dL -1 was lower on AP-HR compared to stdAP, 0.5±2.1% vs 7.4±12.5% (P = 0.028). Time with BG within 70-180 mg dL -1 was higher for the AP-HR admission vs stdAP during the exercise portion and overall (96% vs 87%, and 77% vs 74%), but these did not reach statistical significance (P = 0.075 and P = 0.366). CONCLUSIONS: Heart rate signals can safely and efficaciously be integrated in a wireless AP system to inform of physical activity. While exercise contributes to hypoglycemia among adolescents, even when using an AP system, informing the system of exercise via a HR monitor improved time <70 mg dL -1 . Nonetheless, it did not significantly reduce the total number of hypoglycemic events, which were low in both groups.


Assuntos
Diabetes Mellitus Tipo 1/terapia , Exercício , Frequência Cardíaca , Hiperglicemia/prevenção & controle , Hipoglicemia/prevenção & controle , Monitorização Ambulatorial , Pâncreas Artificial , Adolescente , Algoritmos , Glicemia/análise , Terapia Combinada , Estudos Cross-Over , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/fisiopatologia , Teste de Esforço , Feminino , Hemoglobina A Glicada/análise , Humanos , Hipoglicemia/epidemiologia , Hipoglicemia/etiologia , Hipoglicemia/fisiopatologia , Masculino , Monitorização Ambulatorial/efeitos adversos , Pâncreas Artificial/efeitos adversos , Risco , Índice de Gravidade de Doença , Virginia/epidemiologia , Tecnologia sem Fio
18.
Diabetes Technol Ther ; 18(8): 455-63, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27105121

RESUMO

BACKGROUND: Among postsurgical and critically ill patients, malglycemia is associated with increased complications. Continuous glucose monitoring (CGM) in the inpatient population may enhance glycemic control. CGM reliability may be compromised by postsurgical complications such as edema or vascular changes. We utilized Clarke Error Grid (CEG) and Surveillance Error Grid (SEG) analysis to evaluate CGM performance after total pancreatectomy with islet autotransplantation. MATERIALS AND METHODS: This subanalysis evaluated Medtronic Enlite 2 CGM values against YSI serum glucose in seven post-transplant patients (86% female; 38.6 ± 9.4 years) on artificial pancreas for 72 h at transition from intravenous to subcutaneous insulin. Sensor recalibration occurred for absolute relative difference (ARD) ≥20% x2, ≥30% x1, or by investigator discretion based on trend. RESULTS: Sensor analysis showed mean absolute relative difference (MARD) of 11.0% ± 11.5%. The sensors were recalibrated 8.3 times/day; active sensor was switched 1.4 times/day. Calibration factor was 7.692 ± 3.786 mg/nA·dL (target = 1.5-20 mg/nA·dL). CEG analysis showed 86.1% of pairs in Zone A (clinically accurate zone) and 99.4% of pairs in Zones A + B (low risk of error). SEG analysis of hypoglycemia/hyperglycemia risk showed 92.22% of pairs in the "no risk" zone, 5.96% of pairs in the "slight lower" risk zone, 1.01% of pairs in the "slight higher" risk zone, and only 0.81% of pairs in the "moderate lower" risk zone. CONCLUSIONS: Overall performance of the Medtronic Enlite 2 CGM in the post-transplant population was reasonably good with "no risk" or "slight lower" risk by SEG analysis and high CGM-YSI agreement by CEG analysis; however, frequent recalibrations were required in this intensive care population.


Assuntos
Automonitorização da Glicemia , Insulina/uso terapêutico , Transplante das Ilhotas Pancreáticas/métodos , Pancreatectomia , Adulto , Glicemia/análise , Estado Terminal , Feminino , Humanos , Insulina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Pâncreas Artificial , Reprodutibilidade dos Testes , Transplante Autólogo
19.
Pediatr Diabetes ; 17(1): 28-35, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25348683

RESUMO

OBJECTIVE: The objective of this study was to evaluate the safety and performance of the artificial pancreas (AP) in adolescents with type 1 diabetes (T1D) following insulin omission for food. RESEARCH DESIGN AND METHODS: In a randomized, cross-over trial, adolescents with T1D aged 13-18 yr were enrolled in a randomized, cross-over trial. On separate days, received either usual care (UC) through their home insulin pump or used an AP system (Diabetes Assistant platform, continuous glucose monitor, and insulin pump). Approximately 1 h after admission, participants in both groups received an unannounced snack of 30 g carbohydrate, and 4 h later they received an 80 g lunch, for which both groups only received 75% of the calculated insulin dose to cover carbohydrates. On the UC day (but not the AP day), they received their full high blood glucose (BG) correction factor at lunch. Each admission lasted approximately 8 h. RESULTS: A total of 16 participants completed the trial. On the AP day (compared to UC), mean BG was lower (197 ± 10 vs. 235 ± 14 mg/dL) and time in range 70-180 mg/dL was higher (43% ± 7 vs. 19% ± 7) (both p < 0.05) overall; these results held in the time following the snack and meal (also p < 0.05). During the trial, there were no differences between groups in the rate of hypoglycemia <70 mg/dL. CONCLUSIONS: The AP provided improvements in short-term glycemic control without increases in hypoglycemia following missed insulin for food in adolescents. Thus, the AP partly compensates for missed insulin boluses for food, a common occurrence in adolescent diabetes care. Further testing is needed in longer-term settings.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 1/terapia , Refeições , Pâncreas Artificial/estatística & dados numéricos , Adolescente , Estudos Cross-Over , Diabetes Mellitus Tipo 1/sangue , Feminino , Humanos , Masculino , Período Pós-Prandial , Lanches , Resultado do Tratamento
20.
J Diabetes Sci Technol ; 10(2): 330-5, 2015 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-26553023

RESUMO

BACKGROUND: Previously we have introduced the eA1c-a new approach to real-time tracking of average glycemia and estimation of HbA1c from infrequent self-monitoring (SMBG) data, which was developed and tested in type 2 diabetes. We now test eA1c in type 1 diabetes and assess its relationship to the hemoglobin glycation index (HGI)-an established predictor of complications and treatment effect. METHODS: Reanalysis of previously published 12-month data from 120 patients with type 1 diabetes, age 39.15 (14.35) years, 51/69 males/females, baseline HbA1c = 7.99% (1.48), duration of diabetes 20.28 (12.92) years, number SMBG/day = 4.69 (1.84). Surrogate fasting BG and 7-point daily profiles were derived from these unstructured SMBG data and the previously reported eA1c method was applied without any changes. Following the literature, we calculated HGI = HbA1c - (0.009 × Fasting BG + 6.8). RESULTS: The correlation of eA1c with reference HbA1c was r = .75, and its deviation from reference was MARD = 7.98%; 95% of all eA1c values fell within ±20% from reference. The HGI was well approximated by a linear combination of the eA1c calibration factors: HGI = 0.007552*θ1 + 0.007645*θ2 - 3.154 (P < .0001); 73% of low versus moderate-high HGIs were correctly classified by the same factors as well. CONCLUSIONS: The eA1c procedure developed in type 2 diabetes to track in real-time changes in average glycemia and present the results in HbA1c-equivalent units has shown similar performance in type 1 diabetes. The eA1c calibration factors are highly predictive of the HGI, thereby explaining partially the biological variation causing discrepancies between HbA1c and its linear estimates from SMBG data.


Assuntos
Algoritmos , Automonitorização da Glicemia/métodos , Glicemia/análise , Diabetes Mellitus Tipo 1/sangue , Hemoglobina A Glicada/análise , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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