Ambulatory glucose profile

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Ambulatory glucose profile (AGP) is a single-page, standardized report for interpreting a patient's daily glucose and insulin patterns. AGP provides both graphic and quantitative characterizations of daily glucose patterns. First developed by Drs. Roger Mazze and David Rodbard, [1] with colleagues at the Albert Einstein College of Medicine in 1987, AGP was initially used for the representation of episodic self-monitored blood glucose (SMBG). The first version included a glucose median and inter-quartile ranges graphed as a 24-hour day. Dr. Mazze brought the original AGP to the International Diabetes Center (IDC) in the late 1980s. Since then, IDC has built the AGP into the internationally recognized standard for glucose pattern reporting. [2]

Contents

CaptῡrAGP is a registered trademark of the International Diabetes Center. The AGP, as it is known in the diabetes community, now includes several additional sections: glucose statistics, glucose profile graph, and either daily glucose pattern calendar images or insulin dosage graphs.

Early developments

Near the end of the 1970s two revolutions were taking place that were destined to change the course of diabetes care: the move from urine testing to self-monitored blood glucose (SMBG); and a new measurement for glycation of hemoglobin. The former led to the widespread use of reflectance meters and accompanying glucose oxidase strips to accurately and instantly measure current glucose levels and the latter to an integrated measure of overall glycemic control. The Albert Einstein College of Medicine proved pivotal in both instances. The AGP was first proposed at the Diabetes Research and Training Center (DRTC) and developed by Mazze and associates in the first laboratory to extensively utilize computer technologies in diabetes care.

In the 1970s US Congress was convinced to establish diabetes as a major health concern and to fund research through the National Institutes of Health (NIH). The DRTC program was designed to lead this effort by promoting innovative, multi-disciplinary, translational research focusing on improving diabetes care while still seeking to cure type 1 diabetes and prevent type 2 diabetes. Consequently, the DRTC was very excited about the use of SMBG in clinical decision-making. However, almost right from its introduction a potential problem was identified. Patients were expected to self-test by placing a sample of capillary blood on a strip and inserting the strip into a reflectance meter. The results of the tests (glucose values) were to be recorded in a logbook and brought to the physician.[ citation needed ]

At Einstein, an NIH funded project was undertaken to use SMBG data to devise an algorithm that would determine how much insulin was required to alter blood glucose levels in type 1 diabetes. It quickly became clear that 96 patients testing 4 times a day would produce an enormous amount of data and that these data would somehow have to be copied and recorded by hand on spreadsheets. By happenstance, working with systems analysts, a memory chip was added to the reflectance meter and software was developed to capture the patient data. Using these modified meters in the study patients it was discovered that the data recorded in their logbooks were subject to three errors: over-reporting, under-reporting and imprecision. This resulted in 75% of the research patients providing erroneous glucose data thus thwarting efforts to find an algorithm. [3] Following publication of these results, other investigators confirmed the findings suggesting that patient self-reported data were subject to fabrication and unless independently verified might prove dangerous in terms of clinical decision-making.[ citation needed ]

Based on this mounting evidence, reflectance meter manufacturers quickly converted to memory-based meters with computer printouts. However, despite this revolution, the use of SMBG and electronic reports, although fully supported by the American Diabetes Association, never reached its potential due in part to the popularization of glycated hemoglobin (HbA1c) as the primary basis for clinical decision-making.[ citation needed ]

Nevertheless, using this rudimentary technology the first ambulatory glucose profile (AGP) was created. All data, regardless of date, was plotted by time and subjected to a smoothing algorithm to represent glucose exposure (median) and variability (inter-quartile range). Later the 10th and 90th percentile curves were added to represent outliers. The earliest AGPs characterized daytime glucose patterns as overnight SMBG was sparse.[ citation needed ]

CGM of FGM data are plotted by time ignoring date and subjected to smoothing using five percentile curves: 10th, 25th, 50th (median), 75th and 90th. The top panel is a person with normal glucose metabolism. The center (50th percentile curve) dark line represents overall glucose exposure (mean 89mg/dL). The bottom panel is a person with type 1 diabetes (mean 134mg/dL). The AGP shows significant variability indicated by the darkened area on either side of the median (25th-75th percentile curves--known as inter-quartile range or IQR) is very wide when compared with the normal pattern in the top panel. The IQR represents the area in which 50% of the glucose values will fall. The lighter area on either side of the IQR represents the inter-decile range within which 80% of all values will fall (the area between 10th to 90th percentile curves). The target range, set between 70-180mg/dL, in the bottom panel shows that overnight and mid-afternoon there is a risk of hypoglycemia, while mid-day there is a risk of hyperglycemia. Additionally, while the median curve in the top panel is almost flat, in the bottom panel it oscillates, indicating unstable glucose levels. Ambulatory Glucose Profile Sample Graphs.png
CGM of FGM data are plotted by time ignoring date and subjected to smoothing using five percentile curves: 10th, 25th, 50th (median), 75th and 90th. The top panel is a person with normal glucose metabolism. The center (50th percentile curve) dark line represents overall glucose exposure (mean 89mg/dL). The bottom panel is a person with type 1 diabetes (mean 134mg/dL). The AGP shows significant variability indicated by the darkened area on either side of the median (25th-75th percentile curves--known as inter-quartile range or IQR) is very wide when compared with the normal pattern in the top panel. The IQR represents the area in which 50% of the glucose values will fall. The lighter area on either side of the IQR represents the inter-decile range within which 80% of all values will fall (the area between 10th to 90th percentile curves). The target range, set between 70-180mg/dL, in the bottom panel shows that overnight and mid-afternoon there is a risk of hypoglycemia, while mid-day there is a risk of hyperglycemia. Additionally, while the median curve in the top panel is almost flat, in the bottom panel it oscillates, indicating unstable glucose levels.

A transition to continuous glucose monitoring (CGM)

In 1988 the technology laboratory moved to the International Diabetes Center at Park Nicollet (IDC) in Minnesota. Memory-based reflectance meters with AGP analysis were used in all clinical research projects. AGP was extensively used to characterize abnormalities in pregnancy, type 1 diabetes, and type 2 diabetes. [4] [5] [6] This led to a re-designation of the laboratory as: WHO Collaborating Center for Diabetes Education, Translation and Computer Technologies (a joint program of IDC and Mayo Clinic).

In 2004 continuous glucose monitoring (CGM) was introduced. A small sensor placed under the skin for three days (by 2013 up to 14 days) would measure glucose continuously and transmit the results to a receiver, which would periodically be connected to a PC to produce reports for the health care provider. Because CGM would overcome the episodic nature of SMBG, overnight glucose values, postprandial values and glucose levels during and after activity would be instantly available to the patient and later to the physician for analysis. For most systems, the patient had to calibrate the sensor by SMBG 2-4 times per day and the physician had to off load the data into proprietary non-standardized reports. Nevertheless, with the advent of CGM it was now possible to use AGP analysis to characterize diurnal patterns. [7]

Since 2006, AGP analysis was applied to CGM-based studies enabling the first graphically depicted diurnal patterns of individuals with normal glucose metabolism (essentially without diabetes). [8] [9] [10] [11] ″In recognition of this work the Helmsley Trust awarded a grant to establish AGP as the standard reporting system for CGM and sponsored a special symposium of experts who, after thorough review agreed. [12] Subsequently, other groups reviewed AGP and came to a similar conclusion. [13] [2] [14] [15]

Introduction of flash glucose monitoring (FGM)

In 2013 Abbott Diabetes Care (ADC) became the first company to license the AGP report for use in its newly developed FreeStyle Libre FGM System. [16] Using advanced wired enzyme technology, ADC was able to develop a two-week sensor requiring no calibration by the patient and combined this with an automated AGP reporting system. Shown here (figure to the right) are two AGPs produced by this system: normal glucose metabolism (top panel) and type 1 diabetes (bottom panel). Produced within seconds of uploading the Libre reader, the reports are meant to provide a basis for rapid clinical decisions that are diagnostic, interventional and evaluative. The AGP collapses the two weeks of glucose data and plots only by time allowing for underlying patterns to be identified. It uses five smoothed frequency curves to represent glucose exposure, variability and stability while simultaneously identifying periods of significant hypoglycemia and hyperglycemia. [12]

Building consensus

In February 2017, the Advanced Technology and Treatment for Diabetes Congress, an international body of scientists and clinicians interested in the application of technologies to diabetes care, convened experts from academic centers in research, clinical care and patient advocacy to form a consensus on utilization of continuous glucose monitoring in diabetes care and research. The results of the meeting were published in December 2017. [2] The group, after reviewing various reports used to represent CGM data, concluded that "the AGP approach... is recommended by this consensus group as a standard for visualization of CGM data." In a joint statement of the European Association for the Study of Diabetes and the American Diabetes Association [14] the authors pointed out that "The Ambulatory Glucose Profile (AGP) has been recommended as a potential universal software report that could be adopted to standardize summary metrics among devices and manufacturers." They went on to suggest that AGP measures, inter-quartile range (IQR) and area under the curve (AUC), are currently used to represent glucose variability and exposure, respectively. [14]

In June 2017, at the American Diabetes Association Scientific Meetings in San Diego, CA a panel of experts representing all the major diabetes professional and patient organizations presented their thoughts and recommendations for an international standard for diabetes reporting. The standard suggested the use of 14 key elements to fully articulate the glucose patterns on any report. [17]

AGP has been recognized as an international standard report for glucose patterns. [2] [14] [15] The AGP report is available through IDC's licensing partners: Abbott Diabetes Care, Dexcom, Glooko + Diasend, and Roche. [18] Current AGP reports are now available for self monitoring blood glucose and continuous glucose monitoring devices as well as insulin pumps (tradition and closed loop) and downloadable insulin pens and research. [18] Further AGP report development is ongoing at IDC. [18]

Related Research Articles

<span class="mw-page-title-main">Hypoglycemia</span> Health condition

Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose below 70 mg/dL (3.9 mmol/L), symptoms associated with hypoglycemia, and resolution of symptoms when blood sugar returns to normal. Hypoglycemia may result in headache, tiredness, clumsiness, trouble talking, confusion, fast heart rate, sweating, shakiness, nervousness, hunger, loss of consciousness, seizures, or death. Symptoms typically come on quickly.

<span class="mw-page-title-main">Insulin pump</span> Medical device to administer insulin

An insulin pump is a medical device used for the administration of insulin in the treatment of diabetes mellitus, also known as continuous subcutaneous insulin therapy. The device configuration may vary depending on design. A traditional pump includes:

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<span class="mw-page-title-main">Blood glucose monitoring</span> Use of a glucose monitor for testing the concentration of glucose in the blood

Blood glucose monitoring is the use of a glucose meter for testing the concentration of glucose in the blood (glycemia). Particularly important in diabetes management, a blood glucose test is typically performed by piercing the skin to draw blood, then applying the blood to a chemically active disposable 'test-strip'. The other main option is continuous glucose monitoring (CGM). Different manufacturers use different technology, but most systems measure an electrical characteristic and use this to determine the glucose level in the blood. Skin-prick methods measure capillary blood glucose, whereas CGM correlates interstitial fluid glucose level to blood glucose level. Measurements may occur after fasting or at random nonfasting intervals, each of which informs diagnosis or monitoring in different ways.

<span class="mw-page-title-main">Glucose meter</span> Medical device for determining the concentration of glucose in the blood

A glucose meter, also referred to as a "glucometer", is a medical device for determining the approximate concentration of glucose in the blood. It can also be a strip of glucose paper dipped into a substance and measured to the glucose chart. It is a key element of glucose testing, including home blood glucose monitoring (HBGM) performed by people with diabetes mellitus or hypoglycemia. A small drop of blood, obtained from slightly piercing a fingertip with a lancet, is placed on a disposable test strip that the meter reads and uses to calculate the blood glucose level. The meter then displays the level in units of mg/dL or mmol/L.

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Automated insulin delivery systems are automated systems designed to assist people with insulin-requiring diabetes, by automatically adjusting insulin delivery in response to blood glucose levels. Currently available systems can only deliver a single hormone—insulin. Other systems currently in development aim to improve on current systems by adding one or more additional hormones that can be delivered as needed, providing something closer to the endocrine functionality of the pancreas.

<span class="mw-page-title-main">Diabetes management software</span>

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Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms but people with prediabetes often have obesity, dyslipidemia with high triglycerides and/or low HDL cholesterol, and hypertension. It is also associated with increased risk for cardiovascular disease (CVD). Prediabetes is more accurately considered an early stage of diabetes as health complications associated with type 2 diabetes often occur before the diagnosis of diabetes.

<span class="mw-page-title-main">Minimed Paradigm</span> Insulin pumps

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DexCom, Inc. is a company that develops, manufactures, produces, and distributes continuous glucose monitoring (CGM) systems for diabetes management. It operates internationally with headquarters in San Diego, California, and has manufacturing facilities in Mesa, Arizona and Batu Kawan, Malaysia.

Bruce Bode, MD, FACE is a diabetes specialist with the Atlanta Diabetes Associates in Atlanta, GA and is a clinical associate professor at Emory University in the Department of Medicine. He has served on the board of directors of the Atlanta chapters of the Juvenile Diabetes Research Foundation (JDRF), the American Diabetes Association (ADA), and various Georgia-based diabetes camps. Bode is a member of the board of directors of Glytec and an active member of the JDRF research team validating the efficacy and safety of real-time continuous glucose monitoring (CGMS), and is a former president of the ADA Georgia Affiliate and editor of the ADA's 2004 edition of Medical Management of Type 1 Diabetes.

International Diabetes Center at Park Nicollet (IDC) is a center for diabetes care, research and education located in Minneapolis, Minnesota, United States. The center provides clinical, motivational and educational services for people with diabetes. It is part of HealthPartners Institute.

Tandem Diabetes Care is an American medical device manufacturer based in San Diego, California. The company develops medical technologies for the treatment of diabetes and specifically insulin infusion therapy.

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The Open Artificial Pancreas System (OpenAPS) project is a free and open-source project that aims to make basic artificial pancreas system (APS) technology available to everyone. The OpenAPS project was designed with the idea of quickly getting the APS technology to more people using a direct approach, rather than waiting for clinical trials to be completed and regulatory approval to be granted.

<span class="mw-page-title-main">Continuous glucose monitor</span> Blood glucose monitoring device

A continuous glucose monitor (CGM) is a device used for monitoring blood glucose on a continual basis instead of monitoring glucose levels periodically by drawing a drop of blood from a finger. This is known as continuous glucose monitoring. CGMs are used by people who treat their diabetes with insulin, for example people with type 1 diabetes, type 2 diabetes, or other types of diabetes, such as gestational diabetes.

William V. Tamborlane has been Professor and Chief of Pediatric Endocrinology at Yale School of Medicine since 1986.

Anne Peters is a endocrinologist, diabetes expert, and professor of clinical medicine at the Keck School of Medicine of USC. She runs diabetes centers in well-served Beverly Hills and under-resourced East Los Angeles. She teaches physicians and people with diabetes around the world how to better treat the condition, through lifestyle, medications and technology.

References

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