Publications by authors named "Kristin Castorino"

17 Publications

  • Page 1 of 1

Feasibility of Continuous Ketone Monitoring in Subcutaneous Tissue using a Ketone Sensor.

J Diabetes Sci Technol 2021 Apr 9:19322968211008185. Epub 2021 Apr 9.

Abbott Diabetes Care, Alameda, CA, USA.

Background: The feasibility of measuring β-hydroxybutyrate in ISF using a continuous ketone monitoring (CKM) sensor using a single calibration without further adjustments over 14 days is described.

Methods: A CKM sensor was developed using wired enzyme technology with β-hydroxybutyrate dehydrogenase chemistry. In vitro characterization of the sensor was performed in phosphate buffered saline at 37°C. In vivo performance was evaluated in 12 healthy participants on low carbohydrate diets, who wore 3 ketone sensors on the back of their upper arms to continuously measure ketone levels over 14 days. Reference capillary ketone measurements were performed using Precision Xtra® test strips at least 8 times a day.

Results: The sensor is stable over 14 days and has a linear response over the 0-8 mM range. The operational stability of the sensor is very good with a 2.1% signal change over 14 days. The first human study of the CKM sensor demonstrated that the sensor can continuously track ketones well through the entire 14 days of wear. The performance with a single retrospective calibration of the sensor showed 82.4% of data pairs within 0.225 mM/20% and 91.4% within 0.3 mM/30% of the capillary ketone reference (presented as mM at <1.5 mM and as percentage at or above 1.5 mM). This suggests that the sensor can be used with a single calibration for the 14 days of use.

Conclusions: Measuring ketones in ISF using a continuous ketone sensor is feasible. Additional studies are required to evaluate the performance in intended patient populations, including conditions of ketosis and diabetic ketoacidosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/19322968211008185DOI Listing
April 2021

Protocol for a randomized controlled trial of pre-pregnancy lifestyle intervention to reduce recurrence of gestational diabetes: Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional.

Trials 2021 Apr 7;22(1):256. Epub 2021 Apr 7.

Weight Control and Diabetes Research Center, The Miriam Hospital, Providence, USA.

Background: Gestational diabetes mellitus (GDM) is associated with several maternal complications in pregnancy, including preeclampsia, preterm labor, need for induction of labor, and cesarean delivery as well as increased long-term risks of type 2 diabetes, metabolic syndrome, and cardiovascular disease. Intrauterine exposure to GDM raises the risk for complications in offspring as well, including stillbirth, macrosomia, and birth trauma, and long-term risk of metabolic disease. One of the strongest risk factors for GDM is the occurrence of GDM in a prior pregnancy. Preliminary data from epidemiologic and bariatric surgery studies suggest that reducing body weight before pregnancy can prevent the development of GDM, but no adequately powered trial has tested the effects of a maternal lifestyle intervention before pregnancy to reduce body weight and prevent GDM recurrence.

Methods: The principal aim of the Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional is to determine whether a lifestyle intervention to reduce body weight before pregnancy can reduce GDM recurrence. This two-site trial targets recruitment of 252 women with overweight and obesity who have previous histories of GDM and who plan to have another pregnancy in the next 1-3 years. Women are randomized within site to a comprehensive pre-pregnancy lifestyle intervention to promote weight loss with ongoing treatment until conception or an educational control group. Participants are assessed preconceptionally (at study entry, after 4 months, and at brief quarterly visits until conception), during pregnancy (at 26 weeks' gestation), and at 6 weeks postpartum. The primary outcome is GDM recurrence, and secondary outcomes include fasting glucose, biomarkers of cardiometabolic disease, prenatal and perinatal complications, and changes over time in weight, diet, physical activity, and psychosocial measures.

Discussion: The Gestational Diabetes Prevention /Prevención de la Diabetes Gestacional is the first randomized controlled trial to evaluate the effects of a lifestyle intervention delivered before pregnancy to prevent GDM recurrence. If found effective, the proposed lifestyle intervention could lay the groundwork for shifting current treatment practices towards the interconception period and provide evidence-based preconception counseling to optimize reproductive outcomes and prevent GDM and associated health risks.

Trial Registration: ClinicalTrials.gov NCT02763150 . Registered on May 5, 2016.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13063-021-05204-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024941PMC
April 2021

Accuracy of a 14-Day Factory-Calibrated Continuous Glucose Monitoring System With Advanced Algorithm in Pediatric and Adult Population With Diabetes.

J Diabetes Sci Technol 2020 Sep 19:1932296820958754. Epub 2020 Sep 19.

Abbott Diabetes Care, Alameda, CA, USA.

Background: In this study, we evaluated the analytical performance of the second-generation factory-calibrated FreeStyle Libre Flash Glucose Monitoring (FreeStyle Libre 2) System compared to plasma venous blood glucose reference, Yellow Springs Instrument 2300 (YSI).

Methods: The study enrolled participants aged four and above with type 1 or type 2 diabetes at seven sites in the United States. Adult participants (18+ years) participated in three in-clinic sessions and pediatric participants (4-17 years) participated in up to two in-clinic sessions stratified to provide data for days 1, 2, 3, 7, 8, 9, 12, 13, or 14 of sensor wear. Participants aged 11+ underwent supervised glycemic manipulation during in-clinic sessions to achieve glucose levels across the measurement range of the System. Performance evaluation included accuracy measures such as the proportion of continuous glucose monitoring (CGM) values that were within ±20% or ±20 mg/dL of reference glucose values, and bias measures such as the mean absolute relative difference (MARD) between CGM and reference values.

Results: Data from the 144 adults and 129 pediatric participants were analyzed. Percent of sensor results within ±20%/20 mg/dL of YSI reference were 93.2% and 92.1%, and MARD was 9.2% and 9.7% for the adults and pediatric participants, respectively. The System performed well in the hypoglycemic range, with 94.3% of the results for the adult population and 96.1% of the data for pediatric population being within 15 mg/dL of the YSI reference. The time lag was 2.4 ± 4.6 minutes for adults and 2.1 ± 5.0 minutes for pediatrics.

Conclusions: The System demonstrated improved analytical accuracy performance across the dynamic range during the 14-day sensor wear period as compared to the previous-generation device.NCT#: NCT03607448 and NCT03820050.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1932296820958754DOI Listing
September 2020

Performance of the Dexcom G6 Continuous Glucose Monitoring System in Pregnant Women with Diabetes.

Diabetes Technol Ther 2020 12;22(12):943-947

Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

The aim of this study was to determine the performance of the Dexcom G6 continuous glucose monitoring (CGM) system across three sensor wear sites in pregnant women with diabetes in the second or third trimesters. Participants with type 1 (T1D), type 2 (T2D), or gestational (GDM) diabetes mellitus were enrolled at three sites. Each wore two G6 sensors on the abdomen, upper buttock, and/or posterior upper arm for 10 days and underwent a 6-h clinic session between days 3 and 7 of sensor wear, during which YSI reference blood glucose values were obtained every 30 min. No intentional glucose manipulations were performed. Accuracy metrics included the proportion of CGM values that were within ±20% of paired reference values >100 mg/dL or ±20 mg/dL of YSI values ≤100 mg/dL (hereafter referred to as %20/20), as well as the analogous %15/15, %30/30, and %40/40. The mean absolute relative difference (MARD) between CGM-YSI pairs was also calculated. Thirty-two participants with T1D ( = 20), T2D ( = 3), or GDM ( = 9) were enrolled: 19 were in the second trimester and 13 were in the third trimester of pregnancy. Compared with the reference, 92.5% of CGM values were within ±20%/20 mg/dL. The overall MARD and that of sensors worn on the abdomen, upper buttock, and posterior upper arm was 10.3%, 11.5%, 11.2%, and 8.7%, respectively. There were no device-related adverse events. Skin reactions at the insertion sites were absent or minor. The Dexcom G6 CGM system is accurate and safe in pregnant women with diabetes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/dia.2020.0085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757524PMC
December 2020

A review of prevention strategies for gestational diabetes: is there a missing X-factor?

Minerva Endocrinol 2016 Dec 24;41(4):433-44. Epub 2016 Mar 24.

William Sansum Diabetes Center, Santa Barbara, CA, USA -

Gestational diabetes affects up to one in five pregnancies and can have significant consequences for both mother and baby. There have been great efforts to identify strategies to prevent gestational diabetes during pregnancy. These efforts have been extended to the pre-pregnancy and postpartum periods to address limitations during pregnancy. In this review we explore how diet, exercise and lifestyle modification can be used to prevent gestational diabetes.
View Article and Find Full Text PDF

Download full-text PDF

Source
December 2016

Gestational diabetes mellitus diagnosis and treatment goals: measurement and measures.

Minerva Endocrinol 2016 Jan 29. Epub 2016 Jan 29.

Institution of Endocrinology, Almazov Federal North-West Medical Research Centre, Saint- Petersburg, Russia -

Gestational diabetes mellitus (GDM) is defined as diabetes diagnosed during pregnancy that is not clearly overt diabetes. It is the most common complication of pregnancy and is the most common type of diabetes during pregnancy. Its high prevalence is determined by the increasing epidemic of obesity and by the diagnostic criteria applied. New criteria are currently accepted by a number of professional societies, but considerable controversies still exist concerning diagnosis of GDM. GDM can cause significant short term and long term problems for mother and offspring, including but not limited to cesarean delivery, birth trauma, as well as the development of type 2 diabetes in mother and offspring in the future. Although the consequences of poorly controlled GDM are evident, there continues to be controversy regarding the most appropriate diagnostic criteria, the metabolic aims in controlling GDM, the ability to diagnose GDM in early pregnancy, and the efficiency of treatment in order to improve pregnancy outcomes. This review focuses on current recommendations of professional medical societies and evidence base for GDM diagnosis and glycemic goals of treatment. Available evidence for the optimal time and frequency of self-monitoring of blood glucose and the role of glycated haemoglobin in GDM is also provided in this review.
View Article and Find Full Text PDF

Download full-text PDF

Source
January 2016

Identifying Key Intervention Opportunities During a Pregnancy Complicated by Diabetes: a Review of Acute Complications of Diabetes During Pregnancy.

Curr Diab Rep 2016 Feb;16(2):17

William Sansum Diabetes Center, 2219 Bath St., Santa Barbara, CA, 93105, USA.

Diabetes in pregnancy is associated with significant and sometimes devastating acute complications. It is important that all health care providers are aware of possible complications at each stage of pregnancy so that we can prevent these complications whenever possible and reduce morbidity when they do occur. Most complications associated with diabetes during pregnancy have reduced incidence when blood glucose and blood pressure are optimally controlled. Yet, it is always best to try to optimize diabetes and any comorbidities prior to conception.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11892-015-0710-6DOI Listing
February 2016

Adjustment of Open-Loop Settings to Improve Closed-Loop Results in Type 1 Diabetes: A Multicenter Randomized Trial.

J Clin Endocrinol Metab 2015 Oct 23;100(10):3878-86. Epub 2015 Jul 23.

Department of Chemical Engineering (E.D., R.G., J.B.L., H.C.Z., F.J.D.), University of California Santa Barbara, Santa Barbara, CA 93106; William Sansum Diabetes Center (E.D., J.E.P., R.G., J.B.L., K.C., W.C.B., P.K.B., H.C.Z., F.J.D.), Santa Barbara, CA 93105; Center for Diabetes Technology (S.A.B., S.P., D.L., M.M.-M., C.A.W., B.K.), University of Virginia, Charlottesville, VA 22904; Endocrine Research Unit (A.B., Y.C.K., L.H., A.M., V.D., S.K.M.-S.), Mayo Clinic, Rochester, MN 55905; and Department of Information Engineering (M.S., D.M., C.C.), University of Padova, 35131 Padua, Italy.

Context: Closed-loop control (CLC) relies on an individual's open-loop insulin pump settings to initialize the system. Optimizing open-loop settings before using CLC usually requires significant time and effort.

Objective: The objective was to investigate the effects of a one-time algorithmic adjustment of basal rate and insulin to carbohydrate ratio open-loop settings on the performance of CLC.

Design: This study reports a multicenter, outpatient, randomized, crossover clinical trial.

Patients: Thirty-seven adults with type 1 diabetes were enrolled at three clinical sites.

Interventions: Each subject's insulin pump settings were subject to a one-time algorithmic adjustment based on 1 week of open-loop (i.e., home care) data collection. Subjects then underwent two 27-hour periods of CLC in random order with either unchanged (control) or algorithmic adjusted basal rate and carbohydrate ratio settings (adjusted) used to initialize the zone-model predictive control artificial pancreas controller. Subject's followed their usual meal-plan and had an unannounced exercise session.

Main Outcomes And Measures: Time in the glucose range was 80-140 mg/dL, compared between both arms.

Results: Thirty-two subjects completed the protocol. Median time in CLC was 25.3 hours. The median time in the 80-140 mg/dl range was similar in both groups (39.7% control, 44.2% adjusted). Subjects in both arms of CLC showed minimal time spent less than 70 mg/dl (median 1.34% and 1.37%, respectively). There were no significant differences more than 140 mg/dL.

Conclusions: A one-time algorithmic adjustment of open-loop settings did not alter glucose control in a relatively short duration outpatient closed-loop study. The CLC system proved very robust and adaptable, with minimal (<2%) time spent in the hypoglycemic range in either arm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/jc.2015-2081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596045PMC
October 2015

Early Detection of Physical Activity for People With Type 1 Diabetes Mellitus.

J Diabetes Sci Technol 2015 Jun 30;9(6):1236-45. Epub 2015 Jun 30.

Department of Chemical Engineering, University of California, Santa Barbara, CA, USA William Sansum Diabetes Center, Santa Barbara, CA, USA

Background: Early detection of exercise in individuals with type 1 diabetes mellitus (T1DM) may allow changes in therapy to prevent hypoglycemia. Currently there is limited experience with automated methods that detect the onset and end of exercise in this population. We sought to develop a novel method to quickly and reliably detect the onset and end of exercise in these individuals before significant changes in blood glucose (BG) occur.

Methods: Sixteen adults with T1DM were studied as outpatients using a diary, accelerometer, heart rate monitor, and continuous glucose monitor for 2 days. These data were used to develop a principal component analysis based exercise detection method. Subjects also performed 60 and 30 minute exercise sessions at 30% and 50% predicted heart rate reserve (HRR), respectively. The detection method was applied to the exercise sessions to determine how quickly the detection of start and end of exercise occurred relative to change in BG.

Results: Mild 30% HRR and moderate 50% HRR exercise onset was identified in 6 ± 3 and 5 ± 2 (mean ± SD) minutes, while completion was detected in 3 ± 8 and 6 ± 5 minutes, respectively. BG change from start of exercise to detection time was 1 ± 6 and -1 ± 3 mg/dL, and, from the end of exercise to detection time was 6 ± 4 and -17 ± 13 mg/dL, respectively, for the 2 exercise sessions. False positive and negative ratios were 4 ± 2% and 21 ± 22%.

Conclusions: The novel method for exercise detection identified the onset and end of exercise in approximately 5 minutes, with an average BG change of only -6 mg/dL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1932296815592409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667311PMC
June 2015

Technology and pregnancy.

Diabetes Technol Ther 2015 Feb;17 Suppl 1:S67-75

1 William Sansum Diabetes Center , Santa Barbara, CA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/dia.2015.1508DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4333249PMC
February 2015

Prescribing physical activity to prevent and manage gestational diabetes.

World J Diabetes 2013 Dec;4(6):256-62

Sheri R Colberg, Human Movement Sciences Department, Old Dominion University, Norfolk, VA 23529, United States.

Gestational diabetes mellitus (GDM) is the most prevalent metabolic disorder during pregnancy. Women diagnosed with GDM have a substantially greater risk of developing type 2 diabetes within 5-10 years after delivery, and the risk is increased by excess body weight. Uncontrolled hyperglycemia during pregnancy is potentially harmful to both mother and fetus, resulting in a greater need for Caesarian-section deliveries, delivery of larger infants with more excess body fat, a greater risk of infant death and stillbirth, and an elevated risk of infant hypoglycemia immediately after birth. Fortunately, engaging in physical activity prior to and during pregnancy may lower the risk of developing GDM. Pregnant women should also be advised how to safely increase their physical activity during pregnancy and the postpartum period. An initial approach to becoming more physically active can simply be to encourage women to incorporate more unstructured physical activity into daily living, both before and during pregnancy. Giving women an appropriate exercise prescription can encourage them to participate in physical activity safely and effectively throughout pregnancy to prevent and/or manage GDM. Engaging in 30 min of moderate intensity physical activity on most, if not all, days of the week has been adopted as a recommendation for all pregnant women.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4239/wjd.v4.i6.256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3874484PMC
December 2013

The postpartum management of women with gestational diabetes using a continuum model for health care.

Clin Obstet Gynecol 2013 Dec;56(4):853-9

*Sansum Diabetes Research Institute ‡Department of Bimolecular Science and Engineering, University of California Santa Barbara, Santa Barbara †Keck School of Medicine, University of Southern California, Los Angeles, California.

Women with gestational diabetes mellitus require a continuum of care before, during, and after pregnancy for optimal management of hyperglycemia. Postpartum education and lifestyle modification should begin during pregnancy, and should continue during the postpartum period. Women should receive education on the long-term risk of type 2 diabetes mellitus, and should be encouraged to breastfeed, engage in regular physical activity, and select a highly effective contraceptive method in preparation for subsequent pregnancy. Postpartum women with gestational diabetes mellitus should be empowered to take ownership of their own health, including knowledge of health indicators such as weight, waist circumference hemoglobin A1C levels, and fasting and postprandial blood glucose levels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/GRF.0b013e3182a8e0bbDOI Listing
December 2013

Insulin pumps in pregnancy: using technology to achieve normoglycemia in women with diabetes.

Curr Diab Rep 2012 Feb;12(1):53-9

Sansum Diabetes Research Institute, 2219 Bath Street, Santa Barbara, CA 93105, USA.

Poorly controlled diabetes before conception and during pregnancy among women with pre-existing diabetes can cause major birth defects and spontaneous abortions, as wells as abnormal fetal growth and development including an offspring who is small or large for gestational age, or predisposed to obesity, type 2 diabetes, and metabolic syndrome in his/her lifetime. Conversely, for a woman with pre-existing diabetes, optimizing blood glucose levels before and during early pregnancy can reduce these risks dramatically. As insulin pump technology has evolved, continuous subcutaneous insulin infusion has become a safe and reliable method for treating diabetes during pregnancy. Although pump therapy is often preferred by patients and some experts, insulin pumps have not yet been shown to be superior to multiple daily injections of insulin during pregnancy. In this review of the literature we focus on the use of insulin pumps in the management of diabetes in pregnancy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11892-011-0242-7DOI Listing
February 2012

Pregnancy and diabetes management: advances and controversies.

Clin Chem 2011 Feb 9;57(2):221-30. Epub 2010 Dec 9.

Sansum Diabetes Research Institute, Santa Barbara, CA 93110, USA.

Background: The treatment of diabetes in pregnancy has potentially far-reaching benefits for both pregnant women with diabetes and their children and may provide a cost-effective approach to the prevention of obesity, type 2 diabetes mellitus, and metabolic syndrome. Early and accurate diagnosis of diabetes in pregnancy is necessary for optimizing maternal and fetal outcomes.

Content: Optimal control of diabetes in pregnancy requires achieving normoglycemia at all stages of a woman's pregnancy, including preconception and the postpartum period. In this review we focus on new universal guidelines for the screening and diagnosis of diabetes in pregnancy, including the 75-g oral glucose tolerance test, as well as the controversy surrounding the guidelines. We review the best diagnostic and treatment strategies for the pregestational and intrapartum periods, labor and delivery, and the postpartum period, and discuss management algorithms as well as the safety and efficacy of diabetic medications for use in pregnancy.

Summary: Global guidelines for screening, diagnosis, and classification have been established, and offer the potential to stop the cycle of diabetes and obesity caused by hyperglycemia in pregnancy. Normoglycemia is the goal in all aspects of pregnancy and offers the benefits of decreased short-term and long-term complications of diabetes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1373/clinchem.2010.155382DOI Listing
February 2011