DM: Blood Glucose Self-Monitoring (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To further improve metabolic control with the use of CGMS
Inclusion Criteria:
Pediatric patients with type 1 diabetes and an HbA1c  of 6.8% or above
Exclusion Criteria:
None given
Description of Study Protocol:

Recruitment

32 consecutive pediatric patients with type 1 diabetes, meeting inclusion criteria, who agreed to participate.

Design

Comparison, by HbA1c and number of severe hypoglycemic events, of two methods of gathering information in 27 pediatric subjects to adjust insulin therapy (open study arm using CGMS and blind study arm using self monitoring of glucose information) before and after each three month period for six months

Blinding used (if applicable)

Both patients and diabetes team were blinded to the CGMS profiles in the blind study arm

Intervention (if applicable)

  • In both study arms subjects wore the CGMS for three days every two weeks
  • In the open study arm, information obtained from the CGMS was used to adjust insulin therapy at follow-up visits at six week intervals for three months
  • In the blind study arm information from 7-point self monitoring glucose profiles was used to adjust insulin therapy at follow-up visits at six week intervals for three months (information obtained from the CGMS was not used) 
  • All subjects advised to eat meals at regular intervals, and a low-fat, high-fiber diet with regular physical exercise was recommended

Statistical Analysis

  •  2-sided t test
Data Collection Summary:

Timing of Measurements

Baseline, three and six months.

Dependent Variables

  • CGMS using Medtronic MiniMed, Northridge CA
  • HbA1c using the DCA 2000 from Bayer, Gothenburg, Sweden and adjusted to Swedish national standard (~1.2% below DCCT standard)
  • Severe hypoglycemic events

Independent Variables

  • Duration of type 1 diabetes

 Control Variables

  • Method of insulin therapy (multiple daily injections [MDI]; continuous subcutaneous insulin infusion (CSII)

 

Description of Actual Data Sample:

Initial N: 32 pediatric patients with type 1 diabetes agreed to participate (gender not provided)

Attrition (final N): 27, and 5 patients did not complete all 12 of sensor evaluation periods

Age: 12.5±3.3 years (range 5-19 years)

Ethnicity: not reported

Other relevant demographics:

  • duration of diabetes 7.0±3.9 yrs (range of 2-15)
  • each study arm initially had eight subjects using CSII and eigh who used MDI

Anthropometrics : not reported

Location: Department of Pediatrics, University Hospital, Linkoping and Central Hospital, Uddevalla, Sweden

 

Summary of Results:

 

 

Baseline HbA1c  (%)

 

3 month HbA1c (%)

Statistical Significance

Open study arm (n=27)

7.7

7.31

 p=0.013

Blinded study arm (n=27)

7.75

7.65

 ns

Other Findings

Twenty-six of 27 patients experienced daytime hypoglycemia (5.5% of total time) and all subjects had at least one nocturnal episode of hypoglycemia, with no difference between the two treatment arms nor between the MDI and CSII users.

 

Author Conclusion:
Changes in intensive insulin therapy based on CGMS profiles improved metabolic control in pediatric patients with type 1 diabetes.
Funding Source:
Reviewer Comments:
  • a confounding factor might be the increased number of clinic visits during the study (every six weeks vs two-three months for normal clinic visits)
  • no information provided concerning compliance with recommendations (insulin, diet/exercise)
  • No washout period provided.
  • "Carry over" effect after crossover not discussed.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? ???
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? ???
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes