DM: Blood Glucose Self-Monitoring (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To determine the utility of the continuous glucose monitoring system (CGMS) as an outpatient procedure to improve management of diabetes in poorly controlled adolescents.
Inclusion Criteria:
  • adolescents with poorly controlled (HbA1c) type 1 diabetes
Exclusion Criteria:
None given.
Description of Study Protocol:

Recruitment

Twelve consecutive adolescents meeting inclusion criteria

Design

Comparison of HbA1c and low blood glucose index (LBGI) using CGMS at baseline and two months  (after insulin adjustments were made based on first CGMS) in 12 adolescents with poorly controlled type 2 diabetes

Blinding used (if applicable): no

Intervention (if applicable)

 After CGMS baseline, treatment was adjusted in all patients according to glycemic profiles:

  • modifying dose levels (3)
  • type of insulin administered was changed (7)
  • number of daily injections increased from 2 to 3 (5)
  • insulin injections replaced by CSII (1)

Statistical Analysis

  • Student's t test for paired values
Data Collection Summary:

Timing of Measurements

Baseline and two months after treatment adjustment.  One measure (HbA1c ) reported at six months.

Dependent Variables

  • CGMS by Medtronic-MiniMed, Northridge, CA, and MiniMed Solution software version 2.0
  • HbA1c (method not provided)
  • calculated LBGI (reference is Kruger D, Marcus AO. Diabetes Technol Ther 2000, 2, S93-97)

Independent Variables

  • Duration of type 1 diabetes

Control Variables

  • type of insulin therapy

 

Description of Actual Data Sample:

Initial N: 12 adolescents with type 1 diabetes (5 girls, 7 boys)

Attrition (final N): none reported

Age: 16.2±3 years

Ethnicity: not reported

Other relevant demographics:

  • At baseline, insulin treatment consisted of 2 or 3 daily injections in 10 patients, and CSII in two.
  • mean duration of diabetes: 6.8±2.1 yrs

Anthropometrics : none provided

Location: Timone Hospital for Children, Marseille, France

 

Summary of Results:

 

Variables

Baseline

2 months 6 months

Statistical Significance,

HbA1c (%), n=12 10.3±2.1

8.75±1.06*

 

8.93±1.34+ (see footnote)
LBGI n=7

 1.74±0.9

 2.4±0.4

--

 ns

 *Baseline to 2 mo, p<0.05; +Baseline to 6 mo, significant difference, but p value not provided

Other Findings

  • CGMS at two months vs baseline indicated a significant decrease in the mean frequency of glycemic excursions from 3.5±1.3 to 2.08±1.37 per patient
  • Self-monitoring over the previous 30-day period was significantly higher at two months than at baseline
Author Conclusion:
Use of the CGMS led to a significant improvement in middle-term metabolic control not only by supplying more accurate data for treatment planning, but also by promoting patient communication and motivation.
Funding Source:
Reviewer Comments:
  • Behavioral variables which might have affected outcome (e.g. physical activity, "diet", etc) were not controlled for
  • Sensor performance was suboptimal due to patient- or device-related causes in about 40 percent of cases.
  • While LBGI indicated the risk for severe hypoglycemia to be low, the interpretation of the results should be done cautiously as there were a limited number of capillary measurements before the first CGMS, and the index is not validated in diabetic patients treated by pump and/or insulin analogs.
  • Small sample size

 

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? ???
  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? ???
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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.) N/A
  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? ???
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  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? No
  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? N/A
  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? ???
  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? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? N/A
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? Yes
  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)? N/A
  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? ???
  10.2. Was the study free from apparent conflict of interest? Yes