DM: Self-Monitoring of Blood Glucose (2001)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:

A seven-member panel of experts in diabetes, endocrinology and metabolism were gathered by the American Diabetes Association in 2001 and they produced the following consensus statement. 

Inclusion Criteria:

Cited research used to support their statement include papers from the DCCT, the UKPDS studies, the Stockholm Diabetes Study, and the Kumamoto Study.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Cited research used to support their statement include papers from the DCCT, the UKPDS studies, the Stockholm Diabetes Study, and the Kumamoto Study.  Methods of inclusion not described.

Design

Consensus Statement.

Blinding Used (if applicable):

Not applicable.

Intervention (if applicable):

Not applicable.

Statistical Analysis:

Statistical analysis not completed.

Data Collection Summary:

Timing of Measurements

Not applicable.

Dependent Variables

Not applicable.

Independent Variables

Not applicable.

Control Variables

Description of Actual Data Sample:

Initial N:  7 references cited

Attrition (Final N):  Not applicable

Age:  Not mentioned

Ethnicity:  Not mentioned

Other relevant demographics:

Anthropometrics:

Location:  Worldwide studies

 

Summary of Results:

Management of Diabetes

Health care providers usually assess glycemic control with fasting plasma glucose (FPG), and premeal glucose measurements as well as HbA1c.

Therapeutic goals for HbA1c and preprandial glucose (PPG) measurements have been established based on the results of controlled clinical trials. However, the majority of patients with diabetes fail to achieve their glycemic goals.

New therapies are now available that target PPG.

Definition of Postprandial Plasma Glucose

Postprandial means after a meal. Many factors determine the PPG profile (carbohydrate absorption, insulin and glucagon secretion) and their coordination effects glucose metabolism in the liver and peripheral tissues.  Alterations in these factors in type 1 and type 2 diabetes contribute to elevated PPG.

The magnitude and time of the peak plasma glucose concentration depend on a variety of factors, including the timing, quantity and composition of the meal.

In individuals without diabetes, plasma glucose concentrations peak ~60 minutes after the start of a meal, rarely exceed 140 mg/dL and return to preprandial levels in 2-3 hr, however, absorption of dietary carbohydrate continues for at least 5-6 hr after a meal.  

Type 1 diabetes mellitus:

The time and height of peak insulin concentrations and resultant glucose levels are dependent on the amount, type, and route of insulin administration.

Type 2 diabetes mellitus:

Peak insulin levels are delayed and are insufficient to control PPG excursions adequately.

The measurement of plasma glucose 2-hr after the start of a meal generally approximates peak values in those with diabetes.  There may be situations where 1 hour PPG testing is beneficial (ie. gestational diabetes or GDM).

What is the Relationship among PPG, FPG and HbA1c?

HbA1c provides an indication of the average blood glucose during the preceding 2-3 months, incorporating both pre and postprandial glycemia.

HbA1c does not provide a measure of the magnitude or frequency of short-term fluctations of blood glucose.

Studies have shown a strong correlation between mean plasma glucose (MPG) and HbA1c.  MPG is the average of a multiple of measurements of glucose throughout the day.   With each 1% change in HbA1c, there is a change in about 35 mg/dl MPG.

Type 1 diabetes mellitus:

DCCT data has shown small differences in the relationship between HbA1c and plasma glucose at different times of the day.  Bedtime and post lunch correlated most with HbA1c.  However, no specific times correlated with HbA1c as well as MPG correlated with HbA1c.

Type 2 diabetes mellitus:

In Pima Indians, correlations of HbA1c with FPG and PPG measured 1 and 2 hr after an oral glucose load or a test meal were indistinguishable. In a European study, FPG was found to correlate best with HbA1c; the correlation with PPG was weaker.

What is the Contribution of PPG to the Long-Term Complications of Diabetes?

Epidemiological analyses of the DCCT and UKPDS results reinforce the relationship between chronic glycemia (as measured by HbA1c) and risk for developing long-term complications. However, no clinical trial data address whether PPG, independent of other measures of glycemia, plays a unique role in the pathogenesis of diabetes-specific complications.  Only studies in GDM have examined the need to treat PPG to prevent complications.

Under what Circumstances should People with Diabetes be Tested for PPG?

There are no adequate randomized control trials (except in GDM) to answer this question, but the following are clinical situations which testing PPG could be considered.

  1. Suspected postprandial hyperglycemia, if patients achieve premeal glucose goals, but HbA1c is high.
  2. Patients who are treated with glucose lowering agents to specifically lower PPG, monitoring PPG is important to determine of this goal is met and to evaluate the effect of changes in nutrition or exercise patterns.
  3. Postprandial hypoglycemia, although rare except in response to exercise or rapid acting insulin analogs.

What are the benefits and risks of specifically lowering PPG in an effort to achieve better glycemic control?

There are no unique risks or benefits of PPG treatment that are consistently supported by randomized, controlled studies.

What Additional Research Needs to be Performed to Clarify the Role of PPG in the Medical Management of Diabetes?

Studies should be performed in well-defined patient groups, separating patients by type of diabetes and separating those with impaired glucose tolerance. Elderly, in whom postprandial hyperglycemia may be the most prevalent abnormality in glucose homeostasis, may warrant special attention. Microangiopathy and macroangiopathy should be differentiated as end points. Also, attention must be paid to differences in therapeutic programs (nutrition therapy, vs. oral hypoglycemics, vs. insulin) or any combination of programs.  Considering these principles, the following questions were outlined:

  • How do we best assess postprandial hyperglycemia and the relationships among FPG, PPG, and HbA1C?
  • What is the clinical utility of using measurements of PPG to improve glycemic control?
  • In the presence of equilvalent HbA1C values, does an excessive rise in PPG uniquely affect chronic diabetic complications?

 

Author Conclusion:

There are insufficient data to determine accurately the relative contribution of the FPG and PPG to HbA1c. It appears that FPG is somewhat better than PPG in predicting HbA1c, especially in type 2 diabetes.

There are insufficient data either to support or refute the need for extensive or routine PPG monitoring in diabetes. Since self-monitoring of blood glucose represents a significant financial and personal burden for patients, decisions regarding PPG monitoring should be based on the needs and responses of individual patients.

Funding Source:
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

This Consensus Statement provides a strong argument for not asking patients to routinely do postprandial plasma glucose determinations.  PPG can be appropriately recommended in patients with changes in medications or changes in lifestyle (diet, physical activity) to evaluate glycemic control and to provide data for making decisions to change medications, diet or physical activity for improved glycemic control.

Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? No
 
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? ???
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? ???
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? No
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? No
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes