DM: Blood Glucose Self-Monitoring (2007)
Study 1: To determine if the continuous glucose monitoring system (CGMS) is a more sensitive approach to detecting symptomatic and/or asymptomatic hypoglycemic events (number and duration) in intensively treated (MDI) children with type 1 diabetes as compared with standard monitoring systems
Study 2:
- To determine whether periodic application of CGMS would help to reduce the hypoglycemic risk, without compromising glycometabolic control
- To validate the use of CGMS in childhood
- Children with duration of type 1 diabetes of more than 1 year and absence of ß-cell insulin secretion (C peptide < 0.5 ng/ml)
Recruitment
Children who were regular attendees at the authors' Unit of Autoimmune Endocrine Diseases were recruited.
Design
Study 1: Determine correlation of self-monitoring of blood glucose (SMBG) with CGMS over a 72 hr period in 27 children with type 1 diabetes
Study 2: Comparison of glucose control and hypoglycemic events before and after a 6 week period
Blinding used (if applicable): no
Intervention (if applicable)
Study 2:
- After baseline CGMS, insulin doses were recalculated and redistributed within the 24-hr period
- Subjects were asked NOT to adjust their regular lifestyle (physical activities, dietary habits, social customs during the study)
- Seen by a registered dietitian on a regular basis during the study and instructed to follow a nutritional regimen of 55-60% carbohydrate, 25-30% lipids, and 15-20% protein
Statistical Analysis
- t-test for unpaired data
Timing of Measurements
Baseline and 6 weeks later.
Dependent Variables
- median glycemia by CSII (MiniMed Inc, Sylmar, CA)
- number and duration of hypoglycemic events by CSII as above
- insulin requirements by CSII as above
- SMBG by Glucotrend 2, Roche Diagnostics, Mannheim, Germany
- fructosamine by colorimetric assay (Roche/Hitachi Analyzer)
- HbA1c by spectrophotometric method (Bio-Rad, Richmond, CA)
Independent Variables
- Duration of type 1 diabetes
Control Variables
- Type of insulin delivery (multiple insulin injections)
Initial N:
Study 1: 27 children with type 1 diabetes (12 boys, 15 girls)
Study 2: 18 continued the study through 6 weeks (6 boys, 12 girls)
Attrition (final N): none
Age:
Study 1: median age 10.4±0.8 yrs (range, 6-13.1 yrs)
Study 2: (six weeks): median age 11.3 yrs (range, 6.8-13.1 yrs)
Ethnicity: not reported
Other relevant demographics:
- at baseline, insulin treatment consisted of 4-5 injections per day
- duration of diabetes not provided
Anthropometrics: none provided
Location: Bambino Gesu Children's Hospital, Rome, Italy
Study 2 Variables |
Baseline, n=18 means±SD |
6 weeks, n=18 means±SD |
Statistical Significance of Group Difference |
fructosamine (µmol/L) | 349±24 | 330±30 | P<0.05 |
HbA1c (%) |
7.6±0.7 |
7.5±0.5 |
NS |
Other Findings
Study 1:
- A high level of concordance was obtained between CGMS glycemic values and those obtained using SMBG (median glycemia of 10.58±1.92 mmol/L and 10.74±1.58 respectively, NS)
- CGMS found a significantly higher number of asymptomatic hypoglycemic events vs standard SMBG measurements: 3.6±2.3 vs 0.7±0.9, P<0.0001
Study 2: Insulin therapy adjustments after baseline CGMS had reduced the incidence of hypoglycemia, CGMS vs SMBG (2.5±17 vs 3.9±2.2, P<0.05)
- CGMS is not worthwhile in those individuals with irregular daily living habits and food intake.
- CGMS is a useful device for detecting asymptomatic hypoglycemia and for readjusting glycemic profiles to reduce hypoglycemic events.
- While subjects were asked not to change lifestyle (physical activity, dietary habits, social customs), there was no indication that authors measured compliance for these confounding factors.
- Only one subject was pubertal, so no comparisons can be made between puberty and prepuberty
Quality Criteria Checklist: Primary Research
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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? | 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? | Yes | |
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? | ??? | |
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? | 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? | N/A | |
8. | Was the statistical analysis appropriate for the study design and type of outcome indicators? | Yes | |
8.1. | Were statistical analyses adequately described and the results reported appropriately? | Yes | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | Yes | |
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? | ??? | |
9.1. | Is there a discussion of findings? | Yes | |
9.2. | Are biases and study limitations identified and discussed? | No | |
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 | |