DM: Blood Glucose Self-Monitoring (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of this meta-analysis was to evaluate the effectiveness of self-monitoring of blood glucose at improving blood glucose control in those with type 2 diabetes.

Inclusion Criteria:
  1. Randomized controlled trials (RCTs) that investigated the effectiveness of blood or urine glucose self-monitoring at improving blood glucose control in subjects with type 2 diabetes.
  2. Published trials written in English.
  3. Trials that met the author's quality criteria.

 

Exclusion Criteria:
  1. Non-randomized controlled trials.
  2. Published trials not written in english.
  3. Trials that did not meet author's quality criteria.
Description of Study Protocol:

Recruitment:

Literature search was done for RCTs using Medline, Embase, EBSS, Cochrane Library, authors’ personal reference collections, and hand searches of Diabetes Care, Diabetic Medicine and Diabetologia journals for 1990-1999.  Key words used in literature searches included:  diabetes mellitus and self-monitoring of blood glucose.

Design:  Meta-Analysis

Blinding Used (if applicable):  not applicable

Intervention (if applicable): 

Two authors independently reviewed the studies quality of reporting and to evaluate for internal and external validity (bias and confounding).

Statistical Analysis: 

Meta-analysis done using statistical package: Stata (1999).  Statistical power of the studies was considered separately by estimating whether the study had sufficient power to detect differences in GHb of <3%, <2%, <1%, <0.5%, or <0.25%.  Fixed and random effects analysis was used, as well as tests for heterogeneity.

Data Collection Summary:

Timing of Measurements

Dependent Variables

  • HbA1C

Independent Variables

  • Blood or urine glucose self-monitoring

Control Variables

Description of Actual Data Sample:

Initial N:  Initial search identified 18 studies, of which 10 were excluded because they were non-randomized.

Attrition (Final N):  8 published RCTs were used in this meta-analysis.  One study included subjects taking insulin but the remaining studies included subjects treated with diet or oral diabetes medications.

Age:

The methods used for randomization differed by study and the criteria used for selecting subjects for the studies varied with respect to age distribution, duration of diabetes, quality of blood glucose control and previous experience of monitoring.

Ethnicity:  not mentioned

Other relevant demographics:

Studies also varied with respect to the recommended frequency of self-monitoring, the advice give on modification of therapy, the methods used to assess reliability and adherence to monitoring and duration of the study. Loss to follow-up was substantial in some trials.

Anthropometrics:

Location:  Worldwide studies

Summary of Results:

Other Findings

Overall the quality ratings were generally low. It was estimated that 3 studies had sufficient power to detect differences in HbA1c between 0.5 and 1.0%, 4 studies had only sufficient power to detect differences of more than 1%.

A meta-analysis was performed using data from 4 studies (285 subjects) that compared blood or urine monitoring with no regular monitoring. The estimated decrease in HbA1c from monitoring was –0.25% (95% CI, -0.61% to 0.10%).  

Three studies (278 subjects) that compared blood glucose monitoring with urine glucose monitoring were analyzed. The estimated decrease in HbA1c from monitoring blood glucose rather than urine glucose was –0.03% (-0.52% to 0.47%) which was not statistically different.

Author Conclusion:

In the absence of evidence for clinical effectiveness of blood glucose self-monitoring, there seems little justification for encouraging those with type 2 diabetes to purchase costly testing equipment.

Healthcare costs include not just the costs of equipment and supplies, but also staff time used in busy clinics to teach patients to test, and to review their results.

Further research is needed to clarify the use of self-monitoring in type 2 diabetes so that resources for diabetes care can be used more efficiently. A large randomized trial of the effect of blood glucose self-monitoring in this population is desirable. It would also be feasible to conduct trials of discontinuation of self-monitoring in subjects with stable type 2 diabetes or to do observational studies.

Funding Source:
Government: NHS (UK)
Reviewer Comments:
This meta-analysis reports on the few RCT that have been conducted to evaluate the effectiveness of self-monitoring of glucose to improve glycemic control. Only 8 RCT were identified and the overall quality of the studies was poor with a high drop out rate, small sample size or short study period (3 months). This meta-analysis did not identify studies that included RD intervention.
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? ???
 
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? Yes
  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? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? ???
  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? Yes
  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? No
  10. Was bias due to the review's funding or sponsorship unlikely? Yes