ABCD position statement on continuous glucose monitoring use of by yangxichun



ABCD position statement on continuous
glucose monitoring: use of glucose sensing
in outpatient clinical diabetes care
PJ Hammond*, SA Amiel, CM Dayan, D Kerr, JC Pickup, JAM Shaw, FM Campbell, SA Greene, PC Hindmarsh;
on behalf of the Association of British Clinical Diabetologists (ABCD) and endorsed by the British Society
for Paediatric Endocrinology and Diabetes (BSPED)

Aim                                              Box 1. Definitions
This position statement has been
developed to provide guidance for                 Retrospective monitoring – analysis of blood glucose trends in retrospect;
clinical diabetes teams as to the                 this can be done with retrospective continuous glucose monitoring (CGM),
most effective use of continuous                  where there is no contemporaneous display of sensor readings (blinded
glucose monitoring (CGM), given                   CGM), or by looking at historical data from a real-time monitor either directly
that it is a relatively costly yet                or after downloading onto a PC
valuable resource in guiding
optimisation of glucose lowering                  Real-time monitoring – use of a glucose sensor with a contemporaneous
therapy, and in particular intensive              display of blood glucose values; often there is also a display of glucose
insulin regimens.                                 trends and alarm functions to warn of impending adverse glucose levels

Scope                                             Intermittent use of CGM – this includes use of retrospective CGM (blinded
The authors considered the evi-                   CGM) or real-time CGM over a limited period; the latter may involve the
dence base for CGM, in particular                 wearing of several sensors, e.g. four over 24 days; intermittent use if for
those randomised controlled trials                diagnostic purposes (see below)
which have considered hard
glycaemic endpoints, such as HbA1c                Continuous use of CGM – the expectation is that the user will continuously
and/or frequency of severe hypo-                  wear sensors for at least six days per week; continuous use will usually be for
glycaemia. Recommendations were                   therapeutic purposes (see below)
also based on the authors’ cumula-
tive experience with CGM to                       Diagnostic use of CGM – this is use of sensing to identify specific glucose
allow for any limitations in the                  excursions with the expectation that these can be corrected with a change in
evidence base.                                    therapy without the need for ongoing sensing

Introduction                                      Therapeutic use of CGM – this is ongoing use of sensing to complement
Continuous glucose monitoring                     insulin therapy and allow the user to make real-time changes in response to
(CGM) generates an average                        adverse glucose trends
glucose value every few minutes.
The majority of these devices are                    CGM can be performed retro-            trends in glucose levels on an LCD
inserted subcutaneously and meas-                spectively, where there is no              display and have alarms which can
ure interstitial fluid glucose. They             contemporaneous display of sensor          warn of impending hypoglycaemia
require calibration with capillary               readings, or in real-time where the        or hyperglycaemia.
blood glucose measurements. CGM                  user can view readings on a monitor           It is important to recognise that
can be used in adults and children               allowing immediate adjustment to           there is a lag between the blood and
with diabetes.                                   therapy. Real-time monitors show           interstitial glucose levels of at least

 Peter J Hammond, FRCP, Harrogate                School of Medicine, London, UK            *Correspondence to: Peter Hammond,
 District Hospital, UK                           James AM Shaw, FRCP, University of        FRCP, Consultant Physician, Harrogate
 Stephanie A Amiel, FRCP, King’s College         Newcastle, UK                             District Hospital, Lancaster Park Road,
 School of Medicine, London, UK                  Fiona M Campbell, FRCPCH, St James’s      Harrogate HG2 7SX, UK; e-mail:
 Colin M Dayan, FRCP, University of              Hospital, Leeds, UK             
 Bristol, UK                                     Stephen A Greene, FRCP, Ninewells
 David Kerr, FRCP, Royal Bournemouth             Hospital, Dundee, UK                      Received: 9 December 2009
 Hospital, UK                                    Peter C Hindmarsh, FRCP, University       Accepted: 14 December 2009
 John C Pickup, FRCPath, King’s College          College Hospitals London, UK

66     Pract Diab Int March 2010 Vol. 27 No. 2                                                        Copyright © 2010 John Wiley & Sons
                                                                                            P OSITION S TATEMENT
                        ABCD position statement on use of glucose sensing in outpatient clinical diabetes care

10 minutes. This lag increases when       Box 2. Devices
blood glucose levels are changing
rapidly. Trends in interstitial glucose    Currently available CGM devices
are representative of blood glucose
changes, but absolute interstitial         Enzyme-tipped catheters inserted subcutaneously
glucose values are not always
co-incident with blood glucose             iPro (Medtronic) – retrospective monitoring system; requires calibration
levels. The absolute value should be       with four capillary blood glucose measurements daily; sensor life
confirmed with a capillary blood           six days
glucose measurement before taking          Guardian-REAL-Time/Paradigm Veo (Medtronic) – real-time system;
any therapeutic action.                    requires calibration with two capillary blood glucose measurements daily;
   CGM (retrospective and real-            high/low alarms; trend and predictive functions; six-day sensor life
time) allows:                              FreeStyle Navigator (Abbott) – real-time system; requires calibration with
• Identification of glycaemic excur-       capillary blood glucose measurements at 10, 12, 24 and 72 hours; high/low
sions, both above and below the            alarms; trend and predictive functions; five-day sensor life
individual’s target range.                 DexCom SEVEN (DexCom) – real-time system; requires calibration 12-hourly
• Analysis of the causes of excur-         with capillary blood glucose measurements by One-Touch meter; high/low
sions can be made by reconciling           alarms; trend function; seven-day sensor life
the sensor data with the user
record of:                                 Microdialysis system inserted subcutaneously
  – Insulin doses
  – Food and drink                         GlucoDay (Menarini) – real-time system; requires a one-off calibration
  – Exercise.                              with a capillary blood glucose measurement; high/low alarms; two-day
                                           sensor life
Real-time monitoring additionally
allows the user to take immediate         • Suspected nocturnal hypogly-              When continuous use does not
action in response to adverse             caemia and/or early morning             result in any clinical improvement,
glucose trends.                           hyperglycaemia.                         in terms of either glycaemic control
                                          • Suspected unrecognised hypo-          or patient-related benefit, CGM
Indications for CGM                       glycaemia, e.g. exceptionally low       should be discontinued.
Evidence-based clinical                   HbA1c without reported hypo-
indication                                glycaemia.                              Interpretation
Therapeutic – continuous use of           • HbA1c above individualised target     The key to effective use of CGM is
real-time glucose sensors.                despite intensified insulin therapy     interpretation of the data. The data
• To lower HbA1c, when this               apparently optimised with self-         are most easily viewed in graphical
remains above the individual’s            monitoring.                             form, but clinicians vary in their
target despite optimised use of           • Persistent disabling hypogly-         confidence with handling this
intensive insulin regimens1–4 (MDI        caemia despite conversion from          information. Whilst each clinician –
or insulin pump therapy).                 MDI to CSII.                            and user – needs to work out for
                                          • In pregnancy when HbA1c is            themselves how they can most use-
Potential clinical indications            ≥6.1% or there are problems with        fully interpret the sensor output, a
On the basis of trial evidence and        recurrent hypoglycaemia despite         structured approach is a good
personal experience, the following        optimised intensive insulin therapy.    starting point. One such approach
indications for CGM were reached                                                  is as follows.
by consensus. They are divided into       Therapeutic use – this requires
‘diagnostic’ indications, where a         continuous use of sensors and users     STEP 1. Daily overlay view:
specific problem is solved and            need time to develop their strategies   • Are there clear patterns replicated
treated, or ‘therapeutic’, where          for adjusting therapy according to      on each day, or through part of
CGM can allow a persistent problem        the sensor output.                      each day?
to be addressed.                          • Further optimisation of pump          • To facilitate this, consider sections
                                          therapy regimens when HbA1c             of the day – overnight, first three
Diagnostic use – this will usually        cannot be consistently lowered          hours post-meals, three hours or
involve retrospective CGM. It may         below 7.5% (or 6.1% in pregnancy).      more post-meals.
be done with intermittent short-          • Protection against recurrent
term use of real-time CGM, but the        disabling hypoglycaemia; and for
real-time user can react to the read-     those with hypoglycaemia unaware-
                                                                                  † There is randomised controlled trial
ings which may limit the use of           ness or debilitating fear of hypo-      evidence that use of intermittent retro-
real-time CGM in this setting.            glycaemia.                              spective CGM may result in lower HbA1c
Diagnostic use helps to identify          • Need to ensure avoidance of           levels in the latter stages of pregnancy,
patterns of glucose excursions to         even modest hyperglycaemia, e.g.        and reduced macrosomia rates and
guide therapeutic change.                 pregnancy.†                             birth weight.5

Pract Diab Int March 2010 Vol. 27 No. 2                                             Copyright © 2010 John Wiley & Sons   67
ABCD position statement on use of glucose sensing in outpatient clinical diabetes care

Box 3. National Institute for Health and Clinical Excellence (NICE) advice on             LifeScan and/or NiliMedix, and the
CGM: Clinical Guideline 15                                                                paper was first drafted at a meeting
                                                                                          sponsored by Medtronic.
 Continuous glucose monitoring systems have a role in the assessment of
 glucose profiles in adults with consistent glucose control problems on insulin           References
 therapy, notably:                                                                        1. Garg S, Zisser H, Schwartz S, et al.
                                                                                             Improvement in glycemic excursions
                                                                                             with a transcutaneous, real-time
 • Repeated hyperglycaemia or hypoglycaemia at the same time of day
                                                                                             continuous glucose sensor: a
 • Hypoglycaemia unawareness, unresponsive to conventional insulin dose                      randomized controlled trial. Diabetes
   adjustment                                                                                Care 2006; 29: 44–50.
 • In children and young people with type 1 diabetes who have persistent                  2. Deiss D, Bolinder J, Riveline JP, et al.
   problems with hypoglycaemia unawareness or repeated hypoglycaemia                         Improved glycemic control in poorly
   or hyperglycaemia                                                                         controlled patients with type 1 dia-
                                                                                             betes using real-time continuous
                                                                                             glucose monitoring. Diabetes Care
STEP 2. Daily summaries:                         occasion which was different?               2006; 29: 2730–2732.
• Are there excessive increases or               (e.g. insulin dose or carbohydrate       3. The Juvenile Diabetes Research
decreases?                                       intake).                                    Foundation Continuous Glucose
• Are these related to anything the                                                          Monitoring Study Group. Continu-
user has done, such as exercise,                 STEP 4. If no patterns are identi-          ous glucose monitoring and intensive
snacks, alcohol, work events?                    fied using the first three steps,           treatment of type 1 diabetes. N Engl J
                                                 then block out the target range             Med 2008; 359: 1464–1476.
STEP 3. Consider the pattern on                  on the daily overlay view (e.g.          4. Hirsch IB, Abelseth J, Bode BW,
each day after a specific event, e.g. a          4–10mmol/L) to assess where                 et al. Sensor-augmented insulin
                                                                                             pump therapy: results of the first
specific meal or a specific form                 and when peaks and troughs are
                                                                                             randomized treat-to-target study.
of exercise:                                     occurring.                                  Diabetes Technol Ther 2008; 10:
• Is this glucose profile similar on                                                         378–383.
each occasion after the specific                 Conflict of interest statement           5. Murphy HR, Rayman G, Lewis K, et
event?                                           The authors connected with this             al. Effectiveness of continuous glu-
• Does the glucose profile after the             paper have received research grants         cose monitoring in pregnant women
specific event differ on occasion,               and/or honoraria from Medtronic,            with diabetes: randomised clinical
and, if so, what happened on this                Roche, Abbott, Menarini, DexCom,            trial. BMJ 2008; 337: a1680.


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68     Pract Diab Int March 2010 Vol. 27 No. 2                                                      Copyright © 2010 John Wiley & Sons

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